CN115361535A

CN115361535A - Projection equipment and correction method of projection image thereof

Info

Publication number: CN115361535A
Application number: CN202210745039.0A
Authority: CN
Inventors: 梁倩; 陈许; 罗李浩男; 刘鹏鹏
Original assignee: Qingdao Hisense Laser Display Co Ltd
Current assignee: Qingdao Hisense Laser Display Co Ltd
Priority date: 2022-06-27
Filing date: 2022-06-27
Publication date: 2022-11-18
Anticipated expiration: 2042-06-27
Also published as: CN115361535B

Abstract

The application discloses a projection device and a correction method of a projection image of the projection device. After the projection equipment determines the correction parameters based on the first shot image, the projection equipment can drive the light source assembly by adopting a second driving signal and project the corrected projection image to the projection screen according to the correction parameters. Thus, a good display effect of the projected image can be ensured. Moreover, the first driving signal can enable the color cast degree of the first shot image to be smaller than the threshold value, so that the correction parameters determined by the projection equipment based on the first shot image can be ensured to be more accurate. Furthermore, the correction effect of the projection equipment in correcting the projection image is better, and the display effect of the projection image is further ensured.

Description

Projection equipment and correction method of projection image thereof

Technical Field

The present disclosure relates to the field of electronic technologies, and in particular, to a projection device and a method for correcting a projected image thereof.

Background

The laser projection device may project a projection image onto a projection screen. For the laser projection device, because the light rays are emitted obliquely upward due to the principle of projection imaging, the position between the laser beam emitted by the optical engine in the laser projection device and the projection screen must be strictly aligned.

If the user moves the laser projection device carelessly, the projection image projected and displayed by the laser projection device may exceed the projection screen, resulting in poor display effect of the projection image.

Disclosure of Invention

The application provides a projection device and a projection image correction method thereof, which can solve the problem of poor display effect of a projection image in the related art. The technical scheme is as follows:

in one aspect, a method for correcting a projected image is provided, and is applied to a projection apparatus, where the projection apparatus includes a light source assembly and a camera; the method comprises the following steps:

responding to a correction instruction, driving the light source assembly by adopting a first driving signal, and projecting a corrected image to a projection screen;

acquiring a first shot image obtained by shooting the correction image by the camera;

determining a correction parameter of the projected image based on the first captured image;

driving the light source assembly by adopting a second driving signal, and projecting the corrected projection image to the projection screen according to the correction parameter;

wherein the first drive signal is different from the second drive signal, and the first drive signal is a drive signal capable of making a degree of color cast of the first captured image smaller than a threshold value.

In another aspect, a projection apparatus is provided, the projection apparatus comprising: the device comprises a light source component, a camera and a main control circuit; the master control circuit is configured to:

responding to a correction instruction, driving the light source assembly by adopting a first driving signal, and projecting a corrected image to the projection screen;

In another aspect, a projection apparatus is provided, where a projection host of the projection apparatus includes: a memory, a processor and a computer program stored on the memory, the processor implementing the method of correcting a projected image as described above when executing the computer program.

In yet another aspect, a computer-readable storage medium having instructions stored therein, the instructions being loaded and executed by a processor to implement the method of correcting a projected image as described in the above aspect is provided.

In a further aspect, there is provided a computer program product containing instructions which, when run on a computer, cause the computer to perform the method of correcting a projected image as described in the preceding aspect.

The beneficial effect that technical scheme that this application provided brought includes at least:

the application provides a projection device and a projection image correction method thereof, wherein the projection device can respond to a correction instruction, drive a light source assembly by adopting a first driving signal, and acquire a first shot image obtained by shooting a correction image projected to a projection screen by a camera. After the projection equipment determines the correction parameters based on the first shot image, the projection equipment can drive the light source assembly by adopting a second driving signal and project the corrected projection image to the projection screen according to the correction parameters. Thus, a good display effect of the projected image can be ensured. Moreover, the first driving signal can enable the color cast degree of the first shot image to be smaller than the threshold value, so that the correction parameters determined based on the first shot image can be ensured to be more accurate. Furthermore, the correction effect of the projection equipment in correcting the projection image is better, and the display effect of the projection image is further ensured.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a projection apparatus provided in an embodiment of the present application;

fig. 2 is a schematic structural diagram of an optical engine in a projection apparatus according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of a camera in a projection apparatus provided in an embodiment of the present application;

FIG. 4 is a flowchart of a method for correcting a projected image according to an embodiment of the present disclosure;

FIG. 5 is a flowchart of another method for correcting a projected image according to an embodiment of the present disclosure;

FIG. 6 is a schematic diagram of a corrected image provided by an embodiment of the present application;

fig. 7 is a schematic diagram illustrating a projection host projecting a projection image onto a projection screen according to an embodiment of the present application.

Detailed Description

To make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a projection apparatus according to an embodiment of the present application. As shown in fig. 1, the projection apparatus may include: projection host 10 and projection screen 20. The projection host 10 may include an optical engine 11, a camera 12, and a main control circuit 13.

In the embodiment of the present application, the optical engine 11 is configured to project a projection image to be projected and displayed onto the projection screen 20. The camera 12 is used to photograph the projection image displayed on the projection screen 20 to obtain a photographed image. The main control circuit 13 is configured to correct the display effect of the projection image based on the captured image.

Fig. 2 is a schematic structural diagram of an optical engine provided in an embodiment of the present disclosure, and referring to fig. 2, the optical engine 11 may include a light source assembly 111, a light valve 112, and a projection lens 113.

The light source module 111 is configured to emit a light beam. The light valve 112 is used for modulating the light beam emitted by the light source assembly 111 into an image light beam (i.e., an image to be projected and displayed), and transmitting the image light beam to the projection lens 113. The projection lens 113 is used for projecting the image beam onto the projection screen 20.

Alternatively, the light source assembly 111 may include a plurality of light sources having different colors from each other, and for example, may include at least one of a red light source, a green light source, and a blue light source. And, the plurality of light sources may each be a laser light source, and correspondingly, the projection apparatus may be a laser projection apparatus. For example, the projection device may be an ultra-short-focus laser projection device, which may also be referred to as a laser television. Alternatively, the plurality of light sources may be other types of light sources such as light-emitting diodes (LEDs).

Fig. 3 is a schematic structural diagram of a camera provided in an embodiment of the present application. Referring to fig. 3, the camera 12 may include: a lens 121, a filter 122, an image sensor 123 and a signal processing chip 124. The lens 121 is used to capture an optical image of an object (e.g., a person, a scene, a projected image, etc.) and project the optical image onto a photosensitive surface of the image sensor 123. The image sensor 123 is used for converting an optical image on a photosensitive surface thereof into an electrical signal in a proportional relationship with the optical image.

The filter 122 is located between the lens 121 and the image sensor 123. The filter 122 is used for filtering light within a certain wavelength range, and prevents an optical image collected by the lens 121 from having a photoelectric reaction with the image sensor 123, thereby ensuring that a color difference between a captured image captured by the camera 12 and an image actually viewed by human eyes is small. For example, if the camera 12 is an infrared camera, a filter in the infrared camera may filter out near-infrared light and near-ultraviolet light that are invisible to human eyes.

The signal processing chip 124 is configured to process the electrical signal corresponding to the optical image to obtain image data corresponding to the optical image. The signal processing chip 124 may be integrated with a plurality of signal processing circuits. For example, the signal processing chip 124 may be integrated with a digital-to-analog conversion circuit and a digital processing circuit. The digital-to-analog conversion circuit is used for converting the electrical signal output by the image sensor 123 into a digital signal, and transmitting the digital signal to the digital processing circuit for further processing.

In this embodiment, the main control circuit 13 may include the system on chip and a display control chip, and the system on chip is configured to determine a correction parameter of the projected image based on the captured image and send the correction parameter to the display control chip. The display control chip is used for correcting the display effect of the projection image based on the correction data.

Fig. 4 is a flowchart illustrating a method for correcting a projected image according to an embodiment of the present application, where the method may be applied to a projection apparatus, such as the projection apparatus shown in fig. 1. Referring to fig. 1, a projection host of the projection apparatus includes a light source assembly and a camera. Referring to fig. 4, the method includes:

step 101, responding to a correction instruction, driving a light source assembly by using a first driving signal, and projecting a corrected image to a projection screen.

In the embodiment of the present application, the first driving signal is a driving signal determined based on characteristics of a light source assembly and a camera of the projection host, and is pre-stored in a main control circuit in the projection device. The first drive signal is a drive signal that can make the degree of color cast of a captured image captured by the camera smaller than a threshold value.

When the main control circuit of the projection equipment detects the correction instruction, the first driving signal can be adopted to drive the light source assembly to emit a light beam, and the corrected image is projected to the projection screen. The correction image may be an image dedicated to correction and stored in the main control circuit in advance, and the correction image may also be referred to as a correction chart. The correction image can cover each vertex of the projection screen, and the shape of the correction image and the shape of the projection screen may be the same. For example, the shape of the correction image and the shape of the projection screen may both be quadrilateral.

Alternatively, the corrected image may include a plurality of feature patterns arranged in an array, and the plurality of feature patterns have the same shape, for example, the plurality of feature patterns may all have a cross shape or a rectangular shape.

Alternatively, the correction instruction may be generated for a click operation of a correction button (or a power-on button). The projection host and a remote controller for controlling the projection host can be provided with the correction button (or the starting button). Alternatively, the main control circuit in the projection host may periodically generate a correction instruction and project a corrected image to the projection screen in response to the correction instruction. That is, the master control circuit may periodically perform the calibration procedure. Or, the main control circuit may automatically trigger the correction instruction when detecting that the projection image projected onto the projection screen is deformed or the size of the projection image is different from the size of the projection screen.

And 102, acquiring a first shot image obtained by shooting the corrected image by the camera.

The main control circuit can send a shooting instruction to the camera after projecting the correction image to the projection screen, and the camera can respond to the shooting instruction, shoot the correction image to obtain a first shot image and send the first shot image to the projection host.

Because the camera is when shooing first shot image, the drive signal that is used for driving the light source subassembly is first drive signal, consequently can ensure that the color cast degree of the first shot image that the camera was shot and is obtained is less than the threshold value, and this shooting of first shot image effect is better promptly.

Step 103, determining the correction parameters of the projected image based on the first shot image.

In an embodiment of the present application, the main control circuit may identify a feature pattern in the first captured image, and may determine the correction parameter based on a position of the feature pattern.

As a possible example, the main control circuit may determine a target projection position of the target feature pattern in the projection screen according to the perspective transformation coefficient of the camera and the position of at least one target feature pattern in the corrected image in the first captured image. Wherein the at least one target feature may comprise features located at four vertices of the corrected image. The perspective transformation coefficient may be a variation coefficient between a screen coordinate system of the projection screen and an image coordinate system of the photographed image. The projection host stores the positions of the vertexes of the projection screen in advance. The master control circuitry may determine correction parameters for the projected image based on the offset of the target projection position relative to the position of the respective vertex.

As another possible example, the main control circuit may also identify the positions of the respective vertices of the projection screen in the first captured image. And the main control circuit can determine the offset of each vertex of the at least one target feature graph and the projection screen in the first shot image. Then, the main control circuit may determine an offset of each vertex of the at least one feature pattern and the projection screen in the projection screen coordinate system according to the perspective transformation coefficient of the camera, and further may determine a correction parameter of the projection image based on the offset in the projection screen coordinate system.

In the two examples, the main control circuit may convert the offset amount of the at least one target feature pattern with respect to the position of each vertex of the projection screen to the projection image coordinate system based on a conversion relationship stored in advance, thereby obtaining the pixel offset amount of the projection image. The master control circuitry may then determine a corrected position in the projected image coordinate system for each pixel in the projected image based on the pixel offset.

It can be understood that if the degree of color cast of the first captured image is greater than the preset threshold, the main control circuit may not be able to accurately determine the correction parameter based on the first captured image. In the scheme provided by the embodiment of the application, because the driving signal for driving the light source assembly is the first driving signal when the camera shoots the first shot image, it can be ensured that the correction parameter for determining the projected image based on the first shot image by the main control circuit is more accurate.

And step 104, driving the light source assembly by adopting a second driving signal, and projecting the corrected projection image to a projection screen according to the correction parameter.

In the embodiment of the application, the main control circuit stores the geometric correction algorithm of the projected image in advance. After the main control circuit determines the correction parameters of the projected image, the position of the projected image in the projected image coordinate system can be corrected through the geometric correction algorithm. Then, the main control circuit may drive the light source assembly by using the second driving signal, and project the corrected projection image to the projection screen.

Wherein the second drive signal is different from the first drive signal. The second drive signal may be a drive signal used when the projection device is operating normally, i.e. in a normal viewing mode.

It can be understood that, because the correction parameter that the master control circuit determined based on the first shot image is comparatively accurate, when the master control circuit adopts this correction parameter to rectify the projection image, it can be ensured that the correction effect of this projection image is better, and then the display effect when this projection image is projected to the projection screen is better.

Alternatively, the display effect of the projected image may include a projection position of the projected image on the projection screen, and/or a projection shape of the projected image on the projection screen. The projection position of the projection image after correction is located in the projection screen, and the projection shape of the projection image is the same as the shape of the projection screen. The projection position of the projection image is located in the projection screen, that is, the projection positions of all pixels in the projection image are located in the projection screen, and the projection positions of the edge pixels of the projection image are aligned with the edge of the projection area of the projection screen. The edge pixel of the projection image refers to a pixel located in the outermost peripheral area of the projection image.

In summary, the embodiment of the present application provides a method for correcting a projection image, where the projection apparatus is capable of responding to a correction instruction, driving a light source assembly by using a first driving signal, and acquiring a first captured image obtained by capturing a corrected image projected to a projection screen by a camera. After the projection equipment determines the correction parameters based on the first shot image, the projection equipment can drive the light source assembly by adopting a second driving signal and project the corrected projection image to the projection screen according to the correction parameters. Thus, a good display effect of the projected image can be ensured.

Moreover, the first driving signal can enable the color cast degree of the first shot image to be smaller than the threshold value, so that the correction parameters determined by the projection equipment based on the first shot image can be ensured to be more accurate. Furthermore, the correction effect of the projection equipment in correcting the projection image is better, and the display effect of the projection image is further ensured.

Fig. 5 is a schematic flowchart of another method for correcting a projection image according to an embodiment of the present disclosure. The method can be applied to the projection apparatus shown in fig. 1, and referring to fig. 1 and fig. 2, a projection host of the projection apparatus includes a light source assembly, a camera, and a main control circuit. Referring to fig. 5, the method includes:

step 201, in the process of driving the light source assembly by using the second driving signal and projecting the second reference image to the projection screen, at least one third shot image obtained by shooting the second reference image at least once by the camera without the filter is obtained.

The second reference image may be an image pre-stored in the main control circuit. The second drive signal may be a nominal drive signal of the light source module, and the second drive signal may comprise a plurality of second sub-drive signals for driving a plurality of light sources in the light source module.

Before the projection equipment leaves a factory, the filtering range of a filter adopted in the camera needs to be determined based on the characteristics of a light source component in the projection host and the characteristics of the camera structure. To determine the filtering range, the light source module may be driven with the second driving signal and a second reference image may be projected onto the projection screen. In the process of projecting the second reference image, the camera without the filter can shoot the second reference image at least once, and the main control circuit can acquire at least one third shot image shot by the camera.

Optionally, in order to ensure the accuracy of the determined filtering range, the projection apparatus may be placed in different lighting environments, and the camera without the filter may be controlled to capture the second reference image in different lighting environments, so as to obtain a plurality of third captured images. That is, the plurality of third captured images may be captured in different lighting environments.

It can be understood that if the camera is not provided with the filter, there are more interference waves (for example, infrared waves and ultraviolet light) in the optical image transmitted to the image sensor through the lens of the camera, so that a third captured image captured by the camera on the second reference image has a larger difference from the second reference image actually viewed by human eyes. And compared with the second reference image, the color display effect of the plurality of third shot images is fixedly biased to a certain color.

The biased colors of the third shot images are related to the structure of a projection lens in the projection device and the characteristics of a light source assembly. In different types of projection apparatuses, the color cast condition of a third shot image obtained by shooting the second reference image by a camera is different. For example, in the case of a laser projection apparatus, the plurality of third captured images may be shifted to red.

It can also be understood that the projection device is placed in different illumination environments and shoots the second reference image, so that the influence of external environment factors on the shooting effect of the camera can be effectively eliminated, and the color cast of the third shot image caused by the external environment factors is eliminated.

Step 202, determining a filtering range of the filter based on the color cast of the at least one third shot image.

In this embodiment, the main control circuit may analyze and process the color characteristics of the at least one third captured image by using a preconfigured optical detection method to determine the color cast condition of the at least one third captured image. Because the at least one third captured image has non-uniform color cast due to the influence of the interference wave, the main control circuit may determine, based on the color cast condition of the at least one third captured image, the interference wave that causes the non-uniform color cast of the at least one third captured image, and determine the wavelength of the interference wave. Furthermore, the main control circuit can determine the filtering range of the filter plate based on the wavelength of the interference wave, so as to ensure that the interference wave can be filtered through the filter plate.

The wavelength of the interference wave is located in the filtering range, and the wavelength of the color cast of the at least one third shot image is located outside the filtering range. Therefore, when the filter of the filtering range is placed in the camera and the camera is controlled to shoot images, the shot images with uniform color cast can be ensured to be obtained through shooting.

Optionally, the main control circuit may detect a color cast condition of the at least one third captured image by using a pre-configured color cast detection algorithm, and determine a wavelength of an interference wave that causes the at least one third captured image to generate non-uniform color cast.

Or, the developer may set multiple candidate filters with different filtering ranges in the camera in sequence. The main control circuit can sequentially acquire reference shot images obtained by shooting the second reference image by the camera provided with the alternative filter plates with different filter ranges in the process of projecting the second reference image to the projection screen. The main control circuit may compare the color cast of the plurality of reference captured images with the color cast of the at least one third captured image after the plurality of reference captured images are acquired. In addition, the filtering range of the candidate filter corresponding to the reference shot image with the most uniform color cast in the multiple reference shot images can be determined as the filtering range of the filter to be installed in the camera.

For example, it is assumed that a camera of the projection apparatus, which is not provided with the filter, performs N times of shooting on the second reference image, and N third shot images are obtained. Wherein, N is an integer larger than 1, and the N third shot images all present non-uniform color cast with different degrees. For example, if the middle area of the N third captured images is biased red and the other areas are not biased, the main control circuit may determine that the filter range does not include a red wavelength. The developer can select white glass as a filter of a camera in the laser projection equipment based on the filtering range so as to filter interference waves in the laser projection equipment. Alternatively, if the peripheries of the N third captured images are green and the middle area is not colored, the main control circuit may determine that the filtering range does not include a green wavelength.

And 203, acquiring a second shot image obtained by shooting the first reference image by the camera in the process of driving the light source assembly by adopting the second driving signal and projecting the first reference image to the projection screen.

Before the projection equipment leaves the factory, the light source component can be driven by the second driving signal, and the first reference image is projected to the projection screen. In the process of projecting the first reference image, the camera provided with the filter can shoot the first reference image to obtain a second shot image.

The first reference image may be an image pre-stored in the main control circuit, and the first reference image and the second reference image may be the same or different. The second shot image is obtained by shooting the first reference image through the camera provided with the filter, so that the color cast of the second shot image is uniform.

For example, if the projection apparatus is a laser projection apparatus and the filter in the camera is white glass, the second captured image is a uniformly reddish image.

And step 204, determining the color of the target light source from the plurality of light sources based on the color cast of the second shot image.

In the embodiment of the present application, the light source assembly in the projection host may include a plurality of light sources with different colors. After the main control circuit acquires the second captured image, the color cast condition of the second captured image may be analyzed by using a preset optical detection method to determine the color cast of the second captured image. If the light source assembly comprises a light source with the color same as the color cast of the second shot image, the main control circuit can directly determine the light source as the target light source. If the color cast of the second captured image is different from the colors of the plurality of light sources included in the light source assembly, the main control circuit may determine, as the target light source, a light source in the light source assembly that can synthesize at least two colors of the color cast.

For example, if the light source assembly of the projection apparatus includes light sources with three colors of red, green and blue, and the second captured image is red-biased, the main control circuit may determine that the color of the target light source is red. That is, the master control circuit may determine the red light source in the light source assembly as the target light source. If the second captured image is yellow, the red light source and the green light source in the light source assembly can be determined as the target light source by the main control circuit because the yellow is synthesized by the red light and the green light.

In step 205, a plurality of different driving signals are used to drive the light source module during the process of projecting the third reference image onto the projection screen.

Before the projection equipment leaves a factory, a third reference image can be projected to the projection screen, and in the process of projecting the third reference image, the driving signal of the light source component is adjusted to determine a first driving signal which enables the color cast degree of a shot image obtained by shooting the third reference image by the camera to be smaller than a threshold value. The third reference picture may also be a picture pre-stored in the main control circuit, and the third reference picture may be the same as or different from the first reference picture (or the second reference picture).

In the embodiment, the driving signal of the light source module may include sub-driving signals corresponding to the plurality of light sources one to one. In the process of adjusting the driving signal of the light source assembly, the main control circuit may only adjust the sub-driving signals of the target light source, and the sub-driving signals of other light sources may remain unchanged. That is, among the plurality of different driving signals, the sub driving signals for driving the target light source have different signal values, and the sub driving signals for driving the other light sources have the same signal value.

For example, the main control circuit may gradually increase or decrease the signal value of the sub-driving signal of the target light source in the second driving signal by using the signal value of the second driving signal as a reference value, so as to obtain a plurality of different driving signals. For example, if the light source module includes three color light sources of red, blue and green, and the red light source is the target light source, the main control circuit may gradually decrease the signal values of the sub-driving signals of the red light source in the second driving signal. If the red light source and the green light source are the target light sources, the main control circuit may simultaneously reduce the signal values of the sub-driving signals of the red light source and the sub-driving signals of the green light source in the second driving signal. The reduction amplitude of the signal value of the sub-driving signal of the red light source and the reduction amplitude of the signal value of the sub-driving signal of the green light source can be the same or different.

It can be understood that the magnitude of the signal value of the sub-driving signal corresponding to each light source in the light source module affects the amount of the light beam with a certain color projected by the light source, and further affects the color cast degree of the captured image captured by the camera.

And step 206, acquiring a fourth shot image obtained by shooting the third reference image by the camera in the process of driving the light source assembly by adopting each driving signal.

After the main control circuit adjusts the driving signal every time, a fourth shot image obtained by shooting the third reference image by the camera provided with the filter can be obtained. That is, the main control circuit can acquire a plurality of fourth captured images corresponding to the plurality of driving signals one to one.

It can be understood that, because the sub-driving signals for driving the target light source have different signal values in different driving signals, the degree of color cast of the fourth captured image acquired by the main control circuit is different in the process of driving the light source assembly by using different driving signals. For example, the degree of color cast of the fourth captured image may be positively correlated with the magnitude of the signal value of the sub-drive signal of the target light source, i.e., the smaller the signal value of the sub-drive signal of the target light source, the smaller the degree of color cast of the fourth captured image.

Accordingly, in the above step 205, the main control circuit may gradually decrease the magnitude of the signal value of the sub drive signal of the target light source, and then in this step 206, the main control circuit can acquire the fourth captured image in which the degree of color cast is gradually decreased.

In step 207, one of the plurality of different driving signals, which makes the color cast degree of the fourth captured image smaller than the threshold value, is determined as the first driving signal.

In this embodiment, after the projection device host acquires the plurality of fourth captured images, the color cast degrees of the plurality of fourth captured images may be analyzed to determine whether the color cast degree of the fourth captured image is smaller than a preset threshold.

When the main control circuit determines that the degree of color cast of a certain fourth captured image is less than the threshold value, the driving signal that causes the degree of color cast of the fourth captured image to be less than the threshold value may be determined as the first driving signal. Wherein the first driving signal may include a plurality of first sub-driving signals for driving a plurality of light sources. And, the first sub-driving signal for driving the target light source among the plurality of light sources in the light source module is different from the second sub-driving signal for driving the target light source. The signal value may include a current value, and/or a voltage value.

Alternatively, when the degree of color cast of the fourth captured image is positively correlated with the signal value of the sub-drive signal for driving the target light source in the drive signal, the signal value of the first sub-drive signal for the target light source in the first drive signal is smaller than the signal value of the second sub-drive signal for the target light source in the second drive signal.

It is understood that the above steps 201 to 207 may be steps performed by the projection apparatus before factory shipment to determine the filtering range of the filter in the camera and the signal value of the first driving signal. After the developer of projection equipment determines the filtering range of the filter, the filter in the filtering range can be used as the filter of the camera in the projection equipment and is installed in the camera. And after determining the signal value of the first driving signal, the main control circuit may store the signal value of the first driving signal. After a projection host of the projection equipment is formally delivered to a factory and receives a correction instruction, the light source assembly can be directly driven according to the signal value of the first driving signal.

And step 208, responding to the correction instruction, driving the light source assembly by adopting the first driving signal, and projecting the corrected image to the projection screen.

In the embodiment of the application, after the main control circuit detects the correction instruction, the light source assembly can be driven to emit a light beam by adopting a predetermined first driving signal, and the corrected image is projected to the projection screen. The correction image may be an image dedicated to correction and stored in the main control circuit in advance, and the correction image may also be referred to as a correction chart. The correction image can cover each vertex of the projection screen, and the shape of the correction image and the shape of the projection screen may be the same. For example, the shape of the corrected image and the shape of the projection screen may both be quadrilateral.

Alternatively, the corrected image may include a plurality of feature patterns arranged in an array, and the plurality of feature patterns have the same shape, for example, the plurality of feature patterns may all be cross-shaped or rectangular. For example, referring to fig. 6, the corrected image may include 16 feature patterns arranged in an array, and the feature patterns may be all cross-shaped.

Alternatively, the correction instruction may be generated for a click operation of a correction button (or a power-on button). The projection host and a remote controller for controlling the projection host can be provided with the correction button (or the starting button). Alternatively, the main control circuit in the projection host may periodically generate a correction instruction and project a corrected image to the projection screen in response to the correction instruction. That is, the main control circuit in the projection host may periodically perform the calibration process. Or, the main control circuit may automatically trigger the correction instruction when detecting that the projection image projected onto the projection screen is deformed or the projection area of the projection image is different from the area of the projection screen.

For example, it is assumed that the projection image and the projection screen are both rectangular in shape. If the user carelessly moves the projection host of the projection device during the use of the projection device, referring to fig. 7, the projection image projected to the projection screen by the projection host is deformed (i.e., the shape of the projection image is changed from a rectangle to a trapezoid), and the main control circuit in the projection host can further automatically trigger the correction instruction. The deformation of the projection image may also be referred to as a deflection angle of the projection image.

And step 209, acquiring a first shot image obtained by shooting the corrected image by the camera.

The main control circuit can send a shooting instruction to the camera after projecting the correction image to the projection screen, and the camera can respond to the shooting instruction, shoot the correction image to obtain a first shot image and send the first shot image to the projection equipment.

Because the camera is when shooing first shot image, the drive signal that is used for driving the light source subassembly is first drive signal, consequently can ensure that the color cast degree of the first shot image that the camera was shot and is obtained is less than the threshold value, and this shooting effect of first shot image is better promptly.

Step 210, determining the correction parameters of the projected image based on the first captured image.

In the embodiment of the present application, the main control circuit may recognize the feature pattern in the first captured image, and may determine the correction parameter based on the position of the feature pattern.

As a possible example, the main control circuit may determine a target projection position of the target feature pattern in the projection screen according to the perspective transformation coefficient of the camera and the position of at least one target feature pattern in the corrected image in the first captured image. Wherein the at least one target feature pattern may comprise feature images located at four vertices of the corrected image. The perspective transformation coefficient may be a variation coefficient between a screen coordinate system of the projection screen and an image coordinate system of the photographed image. The projection host stores the positions of the vertexes of the projection screen in advance. The master control circuitry may determine correction parameters for the projected image based on the offset of the target projection position relative to the position of the respective vertex.

The following describes an implementation process of determining the correction parameters of the projected image based on the feature pattern by the main control circuit.

After the main control circuit determines the positions of the vertexes of the projection screen, the main control circuit may determine actual relative positions between the positions of the vertexes of the projection screen and the target projection positions of the feature patterns corresponding to the vertexes on the projection screen, and determine initial relative positions between the positions of the vertexes and the initial projection positions of the feature patterns corresponding to the vertexes. Further, the master control circuit may determine a target offset based on the actual relative position and the initial relative position. The target offset is an offset of a target feature pattern of the corrected image at a target projection position of the projection screen relative to an initial projection position of the projection screen. The initial projection position of the target characteristic graph is the projection position of the target characteristic graph in the projection screen when the corrected image is matched with the projection screen.

Further, the main control circuit may determine, based on the target offset amount, a pixel offset amount of each vertex of the projection image to be displayed in the projection image coordinate system from a correspondence stored in advance, and thereby the main control circuit may determine a correction position of each vertex of the projection image to be displayed in the projection image coordinate system according to the pixel offset amount and an initial position of each vertex of the projection image to be displayed in the projection image coordinate system. The corresponding relationship may be a corresponding relationship between an offset amount in a screen coordinate system and an offset amount in a projection image coordinate system.

It is understood that if the degree of color cast of the first captured image is greater than the preset threshold, the projection apparatus may not be able to accurately determine the correction parameter based on the first captured image. In the scheme provided by the embodiment of the application, because the driving signal for driving the light source assembly is the first driving signal when the camera shoots the first shot image, it can be ensured that the correction parameter for determining the projected image by the projection equipment based on the first shot image is more accurate.

And step 211, driving the light source assembly by adopting a second driving signal, and projecting the corrected projection image to a projection screen according to the correction parameter.

In the embodiment of the application, the main control circuit stores the geometric correction algorithm of the projected image in advance. After the main control circuit determines the correction parameters of the projected image, the position of the projected image in the projected image coordinate system can be corrected through the geometric correction algorithm. Thus, in the projection image coordinate system, the main control circuit can adjust each vertex of the projection image from the initial position to each vertex correction position determined based on the correction parameters. Then, the main control circuit may drive the light source assembly by using the second driving signal, and project the corrected projection image to the projection screen.

It will be appreciated that the master control circuit corrects the position of the projected image in the projected image coordinate system, i.e. corrects the display effect of the projected image when projected onto the projection screen. Because the main control circuit determines that the correction parameter is more accurate based on the first shot image, the main control circuit can ensure that the correction effect of the projected image is better when the correction parameter is adopted to correct the projected image, and further ensure that the display effect of the projected image when the projected image is projected to the projection screen is better.

It can be understood that the order of the steps of the correction method for a projected image provided in the embodiment of the present application may be appropriately adjusted, and the steps may also be deleted according to the circumstances. For example, step 201 and step 202 may be deleted as appropriate. That is, a developer of the projection apparatus may directly use a filter with a known filtering range as the filter of the camera in the projection apparatus. Any method that can be easily conceived by those skilled in the art within the technical scope of the present disclosure is covered by the protection scope of the present disclosure, and thus, the detailed description thereof is omitted.

To sum up, the embodiment of the present application provides a method for correcting a projected image, where a main control circuit in a projection device can respond to a correction instruction, drive a light source assembly by using a first driving signal, and obtain a first captured image obtained by capturing a corrected image projected onto a projection screen by a camera. After the main control circuit determines the correction parameters based on the first shot image, the main control circuit can drive the light source assembly by adopting a second driving signal and project the corrected projection image to the projection screen according to the correction parameters. Thus, a good display effect of the projected image can be ensured.

Moreover, the first driving signal can enable the color cast degree of the first shot image to be smaller than the threshold value, so that the correction parameters determined by the main control circuit based on the first shot image can be ensured to be more accurate. Furthermore, the correction effect of the main control circuit when correcting the projection image is better, and the display effect of the projection image is further ensured.

An embodiment of the present application provides a projection apparatus, as shown in fig. 1 and 7, the projection apparatus may include: a projection host 10 and a projection screen 20, wherein the projection host 10 may include an optical engine 11, a camera 12 and a main control circuit 13. Referring to fig. 2, the optical engine 11 includes a light source assembly 111. The main control circuit 13 is configured to:

in response to the correction instruction, the light source assembly 111 is driven with the first driving signal, and projects a corrected image to the projection screen 20.

A first captured image obtained by capturing the correction image by the camera 12 is acquired.

Correction parameters of the projected image are determined based on the first captured image.

The light source assembly 111 is driven by the second driving signal, and projects the corrected projection image to the projection screen 20 according to the correction parameter.

The first driving signal is different from the second driving signal, and the first driving signal is a driving signal capable of enabling the degree of color cast of the first shot image to be smaller than a threshold value.

Alternatively, the light source assembly 111 includes a plurality of light sources having different colors from each other.

The first driving signal includes a plurality of first sub driving signals for driving the plurality of light sources, and the second driving signal includes a plurality of second sub driving signals for driving the plurality of light sources.

Wherein the first sub-drive signal for driving the target light source among the plurality of light sources is different from the second sub-drive signal for driving the target light source, and the color of the target light source is determined based on the color cast of the camera 12.

Optionally, the main control circuit 13 is further configured to:

in the process of driving the light source assembly 111 by using the second driving signal and projecting the first reference image to the projection screen 20, a second captured image obtained by capturing the first reference image by the camera 12 is obtained.

The color of the target light source is determined from the plurality of light sources based on the color cast of the second captured image.

Optionally, a signal value of a first sub-driving signal of the target light source in the first driving signal is smaller than a signal value of a second sub-driving signal of the target light source in the second driving signal. Wherein the signal value may comprise a current value, and/or a voltage value.

Optionally, referring to fig. 3, the camera head 12 includes a filter 122. The main control circuit 13 is further configured to:

in the process of driving the light source assembly 111 by using the second driving signal and projecting the second reference image to the projection screen 10, at least one third captured image obtained by capturing the second reference image at least once by the camera 12 without the filter 122 is obtained.

The filtering range of the filter 122 is determined based on the color cast of the at least one third captured image.

And the wavelength of the color cast of the at least one third shot image is positioned outside the filtering range.

Optionally, the main control circuit 13 is configured to:

and acquiring a plurality of third shot images obtained by shooting the second reference image by the camera 12 without the filter 122 in a plurality of different lighting environments.

Optionally, the main control circuit 13 is further configured to:

in projecting the third reference image onto the projection screen 10, the light source assembly 111 is driven with a variety of different driving signals.

In the process of driving the light source assembly 111 by using each driving signal, a fourth captured image obtained by capturing the third reference image by the camera 12 is obtained.

Of the plurality of different drive signals, one of the drive signals which makes the degree of color cast of the fourth captured image smaller than the threshold value is determined as the first drive signal.

To sum up, the embodiment of the present application provides a projection device, and this projection is established and can be responded to correction instruction, adopts first drive signal drive light source subassembly to acquire the camera and shoot the first image of shooing that obtains to the correction image that throws to the projection screen. After the projection equipment determines the correction parameters based on the first shot image, the projection equipment can drive the light source assembly by adopting a second driving signal and project the corrected projection image to the projection screen according to the correction parameters. Thus, a good display effect of the projected image can be ensured.

Moreover, the first driving signal can enable the color cast degree of the first shot image to be smaller than the threshold value, so that the correction parameters determined based on the first shot image can be ensured to be more accurate. Furthermore, the correction effect of the projection equipment in correcting the projection image is better, and the display effect of the projection image is further ensured.

It can be understood that the projection apparatus provided in the above embodiments and the embodiment of the method for correcting a projection image of the projection apparatus belong to the same concept, and specific implementation processes thereof are described in the method embodiment and are not described herein again.

The embodiment of the application provides a projection device, and a projection host in the projection device comprises: a memory, a processor and a computer program stored on the memory, the processor implementing the method of correcting a projected image (e.g. the method shown in fig. 4 or 5) as provided in the above method embodiments when executing the computer program.

The embodiment of the application provides a computer-readable storage medium, and the computer-readable storage medium stores instructions which are loaded and executed by a processor to realize the correction method (such as the method shown in fig. 4 or fig. 5) of the projected image provided by the above method embodiment.

Embodiments of the present application provide a computer program product comprising instructions which, when run on a computer, cause the computer to perform a method of correcting a projected image as provided in the above method embodiments (e.g. the method shown in fig. 4 or fig. 5).

It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program instructing relevant hardware, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.

It is to be understood that the term "at least one" in this application refers to one or more, and the meaning of "a plurality" refers to two or more.

The term "and/or" in this application is only one kind of association relationship describing the association object, and means that there may be three kinds of relationships, for example, a and/or B, and may mean: a exists alone, A and B exist simultaneously, and B exists alone.

The terms "first," "second," and the like in this application are used for distinguishing between similar items and items that have substantially the same function or similar functionality, and it should be understood that "first," "second," and "nth" do not have any logical or temporal dependency or limitation on the number or order of execution.

The above description is only exemplary of the present application and should not be taken as limiting the present application, and any modifications, equivalents, improvements and the like that are made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. The correction method of the projection image is characterized by being applied to a projection device, wherein the projection device comprises a light source component and a camera; the method comprises the following steps:

determining a correction parameter of a projected image based on the first captured image;

2. The method of claim 1, wherein the light source assembly comprises a plurality of light sources of different colors from each other;

the first driving signal includes a plurality of first sub-driving signals for driving the plurality of light sources, and the second driving signal includes a plurality of second sub-driving signals for driving the plurality of light sources;

wherein a first sub-driving signal for driving a target light source among the plurality of light sources is different from a second sub-driving signal for driving the target light source, and a color of the target light source is determined based on a color cast of the camera.

3. The method of claim 2, further comprising:

in the process of driving the light source assembly by the second driving signal and projecting the first reference image to the projection screen, acquiring a second shot image obtained by shooting the first reference image by the camera;

determining a color of the target light source from the plurality of light sources based on the color cast of the second captured image.

4. The method of claim 2, wherein a signal value of a first sub-driving signal of the target light source in the first driving signal is smaller than a signal value of a second sub-driving signal of the target light source in the second driving signal;

wherein the signal value comprises a current value, and/or a voltage value.

5. The method of any of claims 1 to 4, wherein the camera comprises a filter; prior to said driving the light source assembly with the first drive signal, the method further comprises:

in the process of driving the light source assembly by the second driving signal and projecting a second reference image to the projection screen, acquiring at least one third shot image obtained by shooting the second reference image for at least one time by the camera without the filter;

determining a filtering range of the filter based on color cast of the at least one third shot image;

wherein the wavelength of the color cast of the at least one third captured image is outside the filtering range.

6. The method according to claim 5, wherein the obtaining at least one third shot image obtained by shooting the second reference image at least once by the camera without the filter segment, comprises:

and acquiring a plurality of third shot images obtained by shooting the second reference image under various different illumination environments by the camera without the filter.

7. The method of any of claims 1 to 4, further comprising:

driving the light source assembly with a plurality of different driving signals during projection of a third reference image onto the projection screen;

acquiring a fourth shot image obtained by shooting the third reference image by the camera in the process of driving the light source assembly by adopting each driving signal;

determining, as the first drive signal, one of the plurality of different drive signals that makes the degree of color cast of the fourth captured image smaller than a threshold.

8. A projection device, characterized in that the projection device comprises: the device comprises a light source component, a camera and a main control circuit; the master control circuit is configured to:

9. The projection device of claim 8, wherein the master circuitry is further configured to:

in the process of driving the light source assembly by adopting the second driving signal and projecting a first reference image to the projection screen, acquiring a second shot image obtained by shooting the first reference image by the camera;

10. The projection device of claim 8 or 9, wherein the camera comprises a filter; the master control circuit is further configured to: