CN114167592B

CN114167592B - Multifunctional lighting module

Info

Publication number: CN114167592B
Application number: CN202111320057.6A
Authority: CN
Inventors: 许星
Original assignee: Orbbec Inc
Current assignee: Orbbec Inc
Priority date: 2018-01-15
Filing date: 2018-01-15
Publication date: 2023-10-27
Anticipated expiration: 2038-01-15
Also published as: CN114167592A; CN108169981A; CN114995015A

Abstract

The application provides a multifunctional lighting module, which comprises a first light source used for emitting a first light beam and a second light source used for emitting a second light beam; the wavelength of the first light beam is different from the wavelength of the second light beam; a diffractive optical element that replicates and expands the first and second light beams; the divergence angle of the first incident light beam formed by the first light beam is not smaller than the included angle between adjacent diffracted light beams formed by the diffraction optical element so as to realize floodlight illumination; the divergence angle of the second incident light beam formed by the second light beam is smaller than the included angle between adjacent diffraction light beams formed by the diffraction optical element so as to realize the illumination of the structured light. The illumination module combines the two functions of floodlight illumination and structured light projection into one module to realize synchronous illumination of floodlight illumination and structured light illumination; meanwhile, the multifunctional module has the characteristics of small volume and low power consumption, and is beneficial to being integrated into intelligent equipment.

Description

Multifunctional lighting module

The application relates to a divisional application of an application patent application with the application number of 201810037171X and the name of multifunctional lighting module.

Technical Field

The application relates to the field of semiconductor illumination, in particular to a multifunctional illumination module.

Background

Visual information is becoming an important way for intelligent equipment to acquire information and sense the world, and along with the continuous increase of functions of the intelligent equipment and the diversification of application scenes, the requirements realized based on the visual information are also becoming wider and wider. For example, the functional requirements of unlocking and payment based on face recognition, gesture and action interaction based on human body information and the like are met, and meanwhile, the functions also need to have higher reliability under different scenes and different environment illumination conditions. The requirements of the traditional equipment are difficult to be met by utilizing a camera to acquire color image information, the visual information acquisition based on active light illumination, such as infrared images, can improve the reliability of visual information acquisition of different scenes and different environment illumination conditions, and the function which is difficult to be realized by utilizing a depth camera to acquire a depth image, such as high-precision face recognition and gesture interaction, can be realized by utilizing a depth camera to acquire the color image. In addition, in cases such as face recognition by using a depth camera, it is necessary to flood illuminate the target at night to realize high-precision recognition.

Infrared illumination, infrared cameras, depth cameras, etc. are increasingly being used in smart devices to obtain visual information such as infrared, depth images, etc. However, this also brings about some problems. The trend toward miniaturization and slimness of smart devices makes it particularly difficult to integrate so many devices. On one hand, more devices bring higher power consumption, so that the cruising ability of the intelligent equipment is reduced; on the other hand, the requirement of the integration of multiple devices on the assembly process is greatly improved, so that the product yield is reduced, and the production cost is increased.

Disclosure of Invention

In order to solve the problems, the application provides a multifunctional lighting module which realizes synchronous illumination of floodlight illumination and structured light illumination.

The application provides a multifunctional lighting module, comprising: a first light source for emitting a first light beam and a second light source for emitting a second light beam; the wavelength of the first light beam is different from the wavelength of the second light beam; a diffractive optical element that replicates and expands the first and second light beams; the divergence angle of a first incident light beam formed by the first light beam is not smaller than an included angle between adjacent diffracted light beams formed by the diffraction optical element, and the first light beam forms floodlight illumination by the diffraction optical element; the divergence angle of the second incident light beam formed by the second light beam is smaller than the included angle between adjacent diffraction light beams formed by the diffraction optical elements, and the second light beam forms structural light illumination by the diffraction optical elements.

In some embodiments, the multifunctional lighting module further includes a lens, the lens is located between the array light source and the diffractive optical element, and the first light beam and the second light beam emitted by the array light source are refracted by the lens to form the incident light beam to be incident on the diffractive optical element. The first light source and/or the second light source comprises an array light source; the lens includes a microlens array, each cell in the microlens array corresponding to a sub-light source in the array light source.

In some embodiments, the diffracted beams are arranged in a regular pattern.

In some embodiments, the diffracted beams are arranged in an irregular pattern.

In some embodiments, the arrangement density of the diffracted beams is non-uniform, and the arrangement density of higher order diffracted beams in the diffracted beams is greater than the arrangement density of lower order diffracted beams.

The present application also provides an image forming apparatus including: a multifunctional lighting module as claimed in any one of the preceding claims for providing flood lighting as well as structured light lighting; the processor is connected with the illumination module and the image sensor, and controls the illumination module to collect floodlight images and structured light images by the image sensor under floodlight illumination and structured light illumination.

In some embodiments, the processor calculates a depth image based on the structured light image.

In some embodiments, the image sensor is a single image sensor, and the imaging device further comprises a filter that allows the first wavelength and second wavelength light beams to pass through.

The application has the beneficial effects that: by arranging two light sources and the diffraction optical elements which are matched with the two light sources, the two functions of floodlight illumination and structured light projection are fused into one module, and the synchronous illumination of the floodlight illumination and structured light illumination is realized; meanwhile, the multifunctional lighting module has the characteristics of small volume and low power consumption, and is beneficial to being integrated into intelligent equipment.

Drawings

FIG. 1 is a schematic view of a floodlight module according to an embodiment of the application.

Fig. 2 is a schematic view of a floodlight module comprising a lens according to an embodiment of the application.

FIG. 3 is a schematic view of a focused illumination according to an embodiment of the present application.

Fig. 4a is a schematic diagram of a regular floodlight pattern according to an embodiment of the application.

FIG. 4b is a schematic diagram of a regular speckle pattern in accordance with one embodiment of the application.

FIG. 5a is a schematic diagram of an irregular floodlight pattern according to an embodiment of the present application.

FIG. 5b is a schematic diagram of an irregular speckle pattern in accordance with one embodiment of the present application.

Fig. 6 is a schematic diagram of a flood pattern with overlapping arrangement in an embodiment of the application.

FIG. 7 is a schematic diagram of a floodlight pattern with varying density according to an embodiment of the present application.

FIG. 8 is a schematic diagram of a flood lighting module including a beam shape modulator according to an embodiment of the present application.

FIG. 9 is a diagram illustrating a floodlight pattern formed by a square beam according to an embodiment of the application.

FIG. 10a is a schematic diagram of an irregular floodlight pattern formed by an array of light sources according to an embodiment of the application.

FIG. 10b is a schematic diagram of irregular spot patterns formed by an array of light sources according to an embodiment of the application.

FIG. 11 is a schematic diagram of a floodlight and structured light illumination module according to an embodiment of the application.

FIG. 12 is a schematic view of a light source according to an embodiment of the application.

FIG. 13 is a schematic diagram of an array light source according to an embodiment of the application.

FIG. 14 is a schematic diagram of a floodlight and structured light illumination module according to an embodiment of the application.

FIG. 15 is a schematic diagram of an imaging device according to an embodiment of the application.

FIG. 16 is a schematic view of dynamic projection according to an embodiment of the application.

Detailed Description

Fig. 1 is a schematic view of a floodlight module according to one embodiment of the application. The module 10 includes a light source 11, and a Diffractive Optical Element (DOE) 12, where the light source 11 may be an LED, a laser, or the like, and is configured to emit light beams such as infrared, ultraviolet, and visible light. The light source 11 emits a beam of light forming an incident beam at the entrance face of the DOE12, the DOE12 receives the incident beam and diffracts the incident beam to spread to a wider space 13 for flood illumination, and in one embodiment the DOE12 functions as a beam splitting, i.e. a single incident beam is replicated and spread into multiple outgoing beams without changing basic properties including beam size, polarization direction, phase, divergence angle, etc. As shown in fig. 1, the light beam emitted from the light source 11 is diffracted by the DOE12 to form outgoing light beams of a plurality of diffraction orders (only-1, 0, 1-order diffraction beams are shown in the figure), and the outgoing light beams illuminate the space 13. For flood lighting purposes, the multiple outgoing beams need to substantially cover and fill the illuminated space 13, where the substantial coverage and fill refers to that the multiple outgoing beams need to cover the illuminated space, so that each area of the illuminated space is illuminated, no distinct non-illuminated area appears, and in an ideal case, the light intensity distribution in the illuminated space is substantially uniform, and referring specifically to fig. 4 (a), 5 (a), 6 and 7, there is no distinct gap between adjacent outgoing beams, and the outgoing beams are adjacent to each other or overlap each other.

In some embodiments, the illumination module is configured to provide active infrared illumination, where the light source 11 may be an edge-emitting laser emitter, a vertical cavity surface laser emitter (VCSEL), or the like, and the beam shape, divergence angle, or the like of the different lasers are different, so that, according to the type of the different lasers, the requirements for implementing flood illumination on the DOE are different, for example, the divergence angle of the edge-emitting laser emitter is greater than that of the vertical cavity surface laser emitter, so that, when the DOE is used to split the beam emitted by the edge-emitting laser emitter, the included angle between the beams of adjacent diffraction orders can be set to be greater when the DOE is designed. In addition, edge-emitting laser emitters often emit beams of elliptical cross-section, so that in order to achieve flood illumination, the angle between adjacent diffracted-order beams in the direction of the major axis of the ellipse can be set smaller than the angle between adjacent diffracted-order beams in the direction of the minor axis of the ellipse when the DOE is designed.

In some embodiments, a lens may also be added between the light source and the DOE in order to further modulate the light source beam to achieve the desired flood illumination. As shown in fig. 2, a lens 20 is disposed between the light source and the DOE, the light source 11 emits a light beam, the lens 20 refracts the light beam emitted from the light source to converge and diverge the light beam, the light beam refracted from the lens forms an incident light beam on an incident surface of the DOE, and the DOE diffracts the incident light beam after receiving the incident light beam and spreads the incident light beam to a target space region. The lens can be a concave lens, a convex lens and the like, the concave lens is used for realizing the divergence of the light beam, and the convex lens is used for realizing the convergence of the light beam. For example, in one embodiment, to increase the distance of flood illumination, the converging lens 20 is configured to reduce the cross-sectional area of the incident beam incident on the DOE, while increasing the intensity of light per unit area, so that a further spatial area may be illuminated after splitting by the DOE; but rather close-range illumination can be achieved by providing a diverging lens 20.

In some embodiments, the control of the DOE incident/exit beam cross-sectional area may also be achieved by setting the distance between the light source and the lens, further controlling the beam intensity. Taking a convex lens as an example, in a range that the distance between the light source and the convex lens is smaller than the focal length of the convex lens, the larger the distance between the light source and the lens is, the larger the cross-sectional area of the light beam incident on the DOE surface is, and conversely, the smaller the cross-sectional area of the light beam incident on the DOE surface is. Fig. 3 shows a schematic view of a focused illumination according to an embodiment of the application. When the distance between the light source and the lens is not smaller than the focal length of the lens, the diffracted light beam can be collimated or focused at a certain position in space. In contrast to fig. 1 and 2, the illumination module will now project a spot patterned beam that can be used for structured light projection.

In addition to using lenses to control beam focusing, the creation of a speckle-patterned beam can also be accomplished by controlling the DOE beam splitting effect. According to the DOE diffraction equation:

sinθ _x ＝m _x λ/P _x (1)

sinθ _y ＝m _y λ/P _y (2)

in the above equation, θ _x 、θ _y Respectively refers to diffraction angles in x and y directions, m _x 、m _y Respectively refers to the diffraction orders along the x and y directions, lambda refers to the wavelength of the light beam, P _x 、P _y Respectively the period of the DOE in the x, y direction, i.e. the dimensions of the basic cell.

From the above diffraction equations, the angle of the diffracted beams is inversely proportional to the period of the fundamental cell on the DOE, so that the angle between adjacent diffracted beams is controlled by controlling the period of the fundamental cell when the DOE is designed, and in general, when the angle between adjacent diffracted beams is larger than the divergence angle of the incident beam on the DOE, a significant gap between adjacent beams can be seen, thereby separating the beams to produce a speckle-patterned beam. Because of errors in the optical system, the relationship between the angle between adjacent diffracted beams and the angle of divergence of the incident beam for spot pattern illumination is not necessarily strictly satisfied, and some access is allowed. In addition, if the incident beam is a focused beam, the divergence angle of the incident beam is unchanged after passing through the diffractive optical element, and the beam may be a speckle pattern near the focusing plane, and further, the overlapping between the beams may cause blurring due to the continued divergence of the beams, in which case, the angle between the divergence angle of the incident beam and the angle between adjacent diffracted beams when the speckle pattern beam is generated in a space with a specific distance may not strictly satisfy the above relationship. Further, the divergence angle of the incident beam is more precisely understood to be the angle formed by the light spot formed by the diffracted beam on a surface (the surface forming the speckle pattern) in space with respect to the diffractive optical element, such as angle a in fig. 1 ₂ As shown. Since the distance between the patterned surface and the diffractive optical element is much greater than the distance between the diffractive optical element and the light source, the angle of divergence a of the incident beam ₁ And an included angle a ₂ Almost equal. When included angle a ₂ When the included angle between adjacent diffraction beams is smaller than the included angle, gaps are reserved between the adjacent beams to form a spot pattern, and when the included angle a ₂ And when the included angle between the adjacent diffraction beams is not smaller than the included angle between the adjacent diffraction beams, overlapping the adjacent beams to form a floodlight pattern. It will thus be appreciated that the relationship between the angles described above is the best example for achieving a patterned beam (hereinafter also a flood beam) and that other slight differences due to errors or other reasons are included in the solution of the application as an exemplary representation.

FIG. 4 is a schematic diagram of a flood pattern and a spot pattern, respectively, according to one embodiment of the present application. Fig. 4 (a) is a flood pattern in which diffracted beams substantially cover a filling space to achieve flood illumination, and fig. 4 (b) is a spot pattern in which diffracted beams are focused to achieve structured light projection. The individual beams of light in the flood pattern are contiguous and substantially cover and fill the illuminated space. There is a significant gap between the individual beams in the speckle pattern to form an independently arranged speckle pattern. In the embodiment shown in fig. 4, the DOE diffracts the light beams in a regular arrangement, which has the advantage of facilitating DOE design and facilitating a more uniform intensity distribution of the flood pattern, and the disadvantage that the speckle pattern is detrimental to the subsequent depth image calculation. Thus, in some embodiments, the DOE is designed such that the arrangement of the light beams is irregular, as shown in fig. 5, where fig. 5 (a) is a floodlight pattern formed by irregular arrangement of the light beams, and fig. 5 (b) is a speckle pattern formed by irregular arrangement of the light beams.

The more uniform the intensity distribution of the flood pattern, the better the quality of the acquired image. In some embodiments, to obtain a flood pattern with a more uniform intensity distribution, the illuminated space is filled by overlapping the beams with each other, as shown in fig. 6. By overlapping each other, gaps between adjacent beams in adjacent arrangements can be avoided, thereby increasing uniformity of pattern intensity distribution.

As the number of diffraction orders increases, the intensity of the light beam is reduced, so that in order to obtain a flood pattern with a relatively uniform intensity distribution, the arrangement density of the light beams is set to a non-uniform form, and in one embodiment, the flood pattern with a relatively uniform intensity distribution is obtained by increasing the arrangement density of the higher-order diffraction order light beams, as shown in fig. 7.

In some embodiments, a relatively uniform pattern of intensity distribution may also be obtained by modulating the beam shape. Fig. 8 is a schematic diagram of an illumination module including a beam shape modulator according to one embodiment of the application. The module comprises a light source, a beam shape modulator 80 and a DOE, wherein the light source emits a light beam, the light beam is modulated by the beam shape modulator 80 to form a preset pattern, and the DOE copies the preset pattern and fills the illuminated space to form a floodlight pattern with relatively uniform beam intensity distribution. In the embodiment shown in fig. 9, the beam shape modulator modulates the beam shape to a square shape, but in other embodiments other shapes may be modulated. The beam shape modulator 80 may be one or a combination of optical elements including refractive, reflective, diffractive, transmissive, masking, and the like. It is understood that any optical element that can modulate a light beam can be used in the present application.

In some embodiments, the light emitting properties of the light source itself may be set directly, such as changing the size and shape of the light emitting aperture to modulate the final pattern. For example, a floodlight pattern as shown in fig. 9 can be realized by configuring a light source emitting a square light beam.

The individual light sources tend to be lower in power and the energy of the individual light beams drops more significantly after splitting through the DOE. For this problem, an array of light sources may be utilized. In one embodiment, a VCSEL array is used as a light source, and the VCSEL array is formed by arranging a plurality of VCSEL light sources on a semiconductor substrate, which has the advantages of small size, low power consumption, and the like. The VCSEL array emits an array beam that is split by the DOE to fill the illuminated space to form a flood pattern, as shown in fig. 10 (a). By controlling the focal length of the lens, the distance between the light source and the lens, etc., the illumination of the spot pattern of the structured light as shown in fig. 10 (b) can be achieved. In the pattern shown in fig. 10, the dotted frame is merely illustrative, and the pattern in the dotted frame corresponds to the VCSEL array light source, and typically, the pattern is generally the same as the arrangement pattern of the VCSEL array light source if no lens is included; if lenses are included, they are generally in a central symmetrical relationship with the array pattern of the VCSEL array light sources. It can be understood that after the array light source is used for replacing the single light source, the single dashed box can be regarded as a single light beam, so that the array light source can be arranged in a similar way to the single light source lighting module, can be regularly arranged or irregularly arranged, can be adjacently arranged or overlapped, and can be arranged in different densities. In the embodiment shown in fig. 10, the coverage of the illuminated space is achieved by a regular, adjacent arrangement between adjacent dashed boxes.

The embodiments described above mainly illustrate that the light source and the DOE are used to implement the floodlight illumination or the structured light illumination/projection, so that the same device is often required to have both the floodlight illumination and the structured light projection in some intelligent devices, and one or both of the floodlight illumination and the structured light illumination are invoked when needed. In devices such as mobile phones, tablets, computers, etc., high-precision face recognition needs to be achieved by acquiring infrared images and depth images, and thus infrared floodlighting and structured light depth cameras are required. It is apparent that integrating a separate infrared floodlight with a separate structured light depth camera into the device can achieve this function, however this increases the cost of the device, increases the manufacturing process difficulties, and in particular miniature smart devices, such as cell phones, which have very limited space to accommodate these devices. In order to solve the problem, the application provides a lighting module with both floodlight lighting and structured light projection, which can realize the switching between the floodlight lighting and the structured light lighting or realize the floodlight lighting and the structured light lighting at the same time.

FIG. 11 is a schematic diagram of a floodlight and structured light illumination module that can be implemented as floodlight illumination or structured light illumination, which can be freely switched between the two, according to one embodiment of the application. The module comprises a light source 111, a lens 112, a DOE113 and an adjuster 114, the adjuster 114 being connected to one or more of the light source 111, the lens 112, the DOE113 for adjustment. The regulator 114 is controlled by the processor to regulate one or more of the light source, lens, DOE to achieve flood illumination or structured light illumination.

In some embodiments, the actuator can achieve different illumination by controlling the movement of the lens 112 and the focal length change, for example, the actuator includes a voice coil motor, the lens is a zoom lens, the voice coil motor is used for controlling the zoom lens to zoom, if the current focal length is larger than the distance between the light source and the lens, the lens diverges the light beam emitted by the light source, and the diverged light beam is suitable for floodlight illumination after being diffracted by the DOE; if the front focal length is smaller than the distance between the light source and the lens, the lens focuses the light beam, and the focused light beam can be used for illumination of the structured light after being diffracted by the DOE. Therefore, by controlling the focal length of the lens by means of the regulator, a single lighting module can be provided with both flood lighting and structured light lighting functions. According to the actual application requirement, the illumination mode required by the current application is transmitted to the regulator in a signal form, and the regulator controls the focal length change of the lens accordingly, so that the corresponding illumination can be realized.

In some embodiments, the diffraction pattern determines how the light beams are replicated and expanded after diffraction, and when the included angle between adjacent diffraction beams is less than or equal to the divergence angle of the incident light beams on the DOE, the replicated light beams can be made to abut or overlap each other to produce flood illumination, and when the included angle between adjacent diffraction beams is greater than the divergence angle of the incident light beams on the DOE, the replicated light beams can be made to be arranged at intervals to produce spot patterned structured light illumination. Two diffraction patterns are simultaneously configured on the same lens substrate, and in actual use, according to specific application requirements (flood lighting or structured light lighting), the regulator can control the movement, rotation and the like of the DOE to correspond to the corresponding diffraction patterns and the light source so as to realize flood lighting or structured light lighting. Such as: the same incidence plane of the DOE is divided into left and right parts, which are configured with different diffraction patterns for generating flood illumination and structured light illumination, respectively, and the modulator corresponds the corresponding diffraction pattern to the light source by controlling the horizontal movement of the DOE. Alternatively, different diffraction patterns are provided on adjacent sides of the DOE for generating flood illumination and structured light illumination, respectively, and the modulator corresponds the respective diffraction patterns to the light source by controlling the rotation of the DOE.

In some embodiments, the regulator achieves different illumination by controlling the light source. Reference is made in particular to the following description of fig. 12, 13, 14.

Fig. 12 is a schematic view of a light source according to one embodiment of the application. The light source is composed of a substrate 121, a first sub-light source 123 and a second sub-light source 122, and the substrate may be a semiconductor substrate, on which the first sub-light source 123 and the second sub-light source 122 are disposed, and a typical light source such as a VCSEL array chip light source. The first sub-light source 123 and the second sub-light source 122 are different in one of the light emitting area, the beam divergence angle, and the like. In one embodiment, the second sub-light source 122 has a smaller light emitting area, and when the light is diffracted by the DOE, there is a significant gap between adjacent light beams projected into the space so as to realize structured light illumination, and the first sub-light source 123 has a larger light emitting area, and the emitted light beams are diffracted by the DOE and split to form a floodlight pattern by adjacent or overlapping between the adjacent light beams; in some embodiments, the divergence angle of the light beams emitted by the second sub-light source 122 is smaller such that the divergence angle of the incident light beam incident on the DOE is smaller than the angle between adjacent diffracted light beams, such that there is a significant gap between the light beams in the pattern, thereby forming a speckle pattern, while the divergence angle of the light beams emitted by the second first light source 123 is larger such that the divergence angle of the incident light beam incident on the DOE is greater than the angle between adjacent light beams, such that the light beams in the pattern are adjacent or overlap, thereby forming a floodlight pattern. It will be appreciated that the present light source based lighting module may or may not include lenses, and that the modulator in the module may provide flood or structured light illumination by independently controlling the different sub-light sources of the light source when illuminated. In a specific application, when floodlight/structured light illumination is desired, a processor in the device transmits a signal to the regulator and controls the regulator to adjust to achieve floodlight/structured light illumination.

Fig. 13 is a schematic view of a light source according to yet another embodiment of the application. Unlike the light source in fig. 12, on the substrate 131, the first sub-light source 132 and the second sub-light source 133 are both in the form of an array. It will be appreciated that the first sub-light sources for achieving flood lighting and the second sub-light sources for achieving structured light lighting may be the same or different in number; the first sub-light source and the second sub-light source can be separated and evenly distributed or can be distributed in a crossed mode. In one embodiment, only 1 first sub-light source is used for flood illumination, while a plurality of second sub-light sources are utilized for structured light illumination. The first light source and the second light source may be on the same substrate or on different substrates.

In some embodiments, the first sub-light source and the second sub-light source may also be light sources with the same light emitting attribute, and in the lighting module based on the light sources, the floodlight lighting and the structured light lighting are realized by setting lenses with different attributes and the light sources. Fig. 14 is a schematic view of a floodlight and structured light illumination module according to yet another embodiment of the present application, the module comprises a light source composed of a substrate 141, a first sub-light source 143, a second sub-light source 142, a lens composed of a first lens 145, a second lens 144, and a DOE146. The lenses herein may also be a microlens array MLA, where the microlens units in the MLA correspond to sub-light sources in the light source array. The first sub-light source 143 is diffracted by the DOE146 via the first lens 145 to achieve flood illumination, and the second sub-light source 142 is diffracted by the DOE146 via the second lens 144 to achieve structured light illumination. The regulator in the module may implement flood lighting or structured light lighting of the module by controlling the turning on or off of the first sub-light source 143 and the second sub-light source 144. In some embodiments, flood lighting and structured light lighting may also be implemented in the lighting module by setting DOEs of different properties corresponding to the first and second sub-light sources. For example, a first DOE corresponding to a first sub-light source is adjacent to an adjacent light beam when splitting the light beam, and a second DOE corresponding to a second sub-light source is spaced apart from the adjacent light beam when splitting the light beam, thereby achieving floodlight and structured light illumination, where the first DOE and the second DOE may be fabricated on the same substrate.

In some embodiments, the first light source and the second light source have different wavelengths, such as near infrared light and far infrared light, in addition to the different properties to generate the flood illumination and the structured light illumination, respectively. Because the wavelengths are different, the first light source and the second light source can be simultaneously turned on to realize synchronous illumination of floodlight illumination and structured light illumination.

The application further provides an imaging device based on the illumination module. Fig. 15 is a schematic view of an image forming apparatus according to an embodiment of the present application. The device comprises an illumination module 159, a processor 153 and a collection module 158, wherein the illumination module 159 is used for illuminating a space by emitting light with a certain wavelength, and the collection module 158 generally comprises a filter corresponding to the wavelength so as to image the light reflected by an object in the space. The lighting module 159 includes a regulator 154, a light source 155, a lens 156 and a DOE157, and after the processor 153 sends out a corresponding lighting signal, the regulator 154 adjusts one or more of the light source, the lens and the DOE to achieve corresponding lighting, such as flood lighting or structured light lighting. The imaging module 158 includes an image sensor 151 and a lens 152, wherein light reflected by an object in space is imaged on the image sensor 151 through the lens 152, the image sensor 151 may be a CCD or CMOS, and the image sensor 151 converts an optical signal into an electrical signal and transmits the electrical signal to the processor 153 for processing to form an image. The acquisition module 151 may also include an image processor, such as a DSP, where the electrical signals are processed by the DSP to form an image and transmitted to the processor. The processor 153 controls the illumination module 159 and the acquisition module 158 to acquire floodlight images and structural spot patterns of the imaging device. In addition, the processor 153 may further calculate a depth image using the speckle pattern. In one embodiment, the processor may also fuse the depth image with the floodlight image to output an image that contains both depth and texture information.

For the situation of floodlight illumination and structured light illumination synchronous illumination, a plurality of acquisition modules can be arranged to synchronously acquire floodlight images and structured light images. Preferably, in the single acquisition module, the optical filters allowing the wavelengths corresponding to the first light source and the second light source are configured to synchronously acquire floodlight and structured light information on the single image sensor, and the floodlight image and the structured light image are segmented through later image processing.

Problems are often encountered when image acquisition is performed with imaging devices. For example, for floodlight image acquisition, when the light beam with the same wavelength as the light source exists in the ambient light, and the ambient light changes obviously, the floodlight image acquisition is affected; for depth image acquisition, when the depth change of the target is obvious, the spot sizes of the target at different depths are different, and the subsequent depth image calculation accuracy is affected. The application provides an imaging device based on dynamic illumination. The imaging device can realize: dynamic projection under flood illumination, dynamic projection under structured light illumination, and dynamic switched projection between flood illumination and structured light illumination.

FIG. 16 is a schematic view of dynamic projection according to one embodiment of the application. Taking structural spot diagram projection as an example (which is also applicable to floodlighting), in the process of acquiring images by utilizing an acquisition module, one or more of a light source, a lens and a DOE in the illumination module are controlled by a processor to realize dynamic illumination, in one embodiment, a plurality of images are acquired by controlling a regulator to realize dynamic illumination, and finally the acquired images are fused by the processor to generate a high-quality image.

In one embodiment, the adjuster is used to control the focal length of the lens to focus the target space at different distances and to simultaneously acquire corresponding images, such as images 161, 162, 163 acquired at different distances in FIG. 16, where the spots projected onto a portion of the target object are most concentrated when that portion is located exactly near the plane of the current focal length, with the corresponding spot contrast being highest (e.g., spot 166) in the acquired image and relatively low (e.g., spot 165) for spots that are not in the focal plane. After multiple images are acquired, a single high quality image 164 can be acquired by a speckle pattern recognition and fusion algorithm.

In one embodiment, the processor may also be used to control the regulator to regulate during a single frame image acquisition period, i.e., the illumination module continuously changes its illumination state during the exposure time of a single frame image, so that the acquired image has better image quality relative to the only illumination. Compared with the multi-frame image fusion mode, the method does not need subsequent calculation. For example, in the above embodiment, the illumination mode of filling the illuminated space is covered by copying and expanding the light beams, and the intensity distribution of the single light beam and the intensity distribution between the light beams are difficult to be completely uniform, so that the effect of the flood illumination cannot be optimized. In addition, for the illumination of the structured light, the focusing problem of objects in space at different distances is also faced, namely, the distances are different, the contrast of spots is different, and the contrast difference in the structured light images acquired under the single illumination condition is larger. In order to solve the problem, the processor can also be used for controlling the changes of factors such as the focal length of the lens in the illumination module and the like in a single frame exposure period of the image sensor so as to increase the contrast of spots in the finally acquired structured light image.

The foregoing is a further detailed description of the application in connection with specific/preferred embodiments, and it is not intended that the application be limited to such description. It will be apparent to those skilled in the art that several alternatives or modifications can be made to the described embodiments without departing from the spirit of the application, and these alternatives or modifications should be considered to be within the scope of the application.

Claims

1. A multifunctional lighting module, comprising:

a first light source for emitting a first light beam, a second light source for emitting a second light beam; the wavelength of the first light beam is different from the wavelength of the second light beam;

a diffractive optical element that replicates and expands the first and second light beams;

the divergence angle of a first incident light beam formed by the first light beam is not smaller than an included angle between adjacent diffracted light beams formed by the diffraction optical element, and the first light beam forms floodlight illumination by the diffraction optical element; the diffraction light beams formed by the first light beams are arranged in a regular form or an irregular form;

the divergence angle of a second incident light beam formed by the second light beam is smaller than the included angle between adjacent diffraction light beams formed by the diffraction optical elements, and the second light beam forms structural light illumination by the diffraction optical elements; the diffraction light beams formed by the second light beams are arranged in a regular form or an irregular form;

therefore, the two functions of floodlight illumination and structured light projection are integrated into one illumination module.

2. The multi-function lighting module of claim 1, wherein the first light source and the second light source are turned on simultaneously to achieve simultaneous illumination of flood illumination and structured light illumination.

3. The multifunctional lighting module of claim 1, further comprising a lens, wherein the first light source and/or the second light source comprises an array light source, the lens is located between the array light source and the diffractive optical element, and the first light beam and the second light beam emitted by the array light source are refracted by the lens to form the incident light beam to be incident on the diffractive optical element.

4. A multi-function lighting module as recited in claim 3, wherein said lens comprises a microlens array, each cell in said microlens array corresponding to a sub-light source in said array light source.

5. The multifunctional lighting module of any one of claims 1-4, wherein the arrangement density of the diffracted beams is non-uniform.

6. The multifunctional lighting module of any one of claims 1-4, wherein the arrangement density of higher order diffracted beams is greater than the arrangement density of lower order diffracted beams in the diffracted beams.

7. An image forming apparatus, comprising:

the multifunctional lighting module of any one of claims 1-6, configured to provide flood lighting and structured light lighting;

the processor is connected with the illumination module and the image sensor, and controls the illumination module to collect floodlight images and structured light images by the image sensor under floodlight illumination and structured light illumination.

8. The imaging apparatus of claim 7, wherein the processor calculates a depth image based on the structured light image.

9. The imaging apparatus of claim 7, wherein the image sensor is a single image sensor, the imaging apparatus further comprising a filter that allows light beams of a first wavelength and a second wavelength to pass through to enable simultaneous acquisition of flood and structured light information on the single image sensor, the flood and structured light images being separable by post image processing.