CN114998450A - TOF camera calibration method and system - Google Patents
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Abstract
The invention provides a TOF camera calibration method and a TOF camera calibration system, wherein the TOF camera calibration method comprises the following steps: constructing a first fitting model, a second fitting model and a third fitting model according to the first actual depth information, the first measured gray scale information and the first exposure time; correcting swing errors caused by different depths of the second shot object according to the first fitting model by using the second actual depth information as reference and using the second measured depth information; and correcting depth errors caused by different reflection conditions of the second shot object according to the second fitting model and the third fitting model by using the second measured depth information, the second exposure time and the second measured gray scale information, so as to obtain calibrated measured depth information, wherein the calibrated measured depth information can be suitable for calibration of different exposure times, different shot objects and different distances between the shot objects and the TOF camera, and the accuracy and precision of a calibration result of the TOF camera are ensured.
Description
Technical Field
The invention relates to the technical field of images, in particular to a TOF camera calibration method and a TOF camera calibration system.
Background
Three-dimensional cameras based on the TOF (Time-Of-Flight) theory are one Of the research hotspots in the current technology, and TOF three-dimensional cameras (TOF cameras for short) have gradually appeared in the system fields Of gesture control, 3D modeling, automobile radar, robot vision and the like.
The TOF camera adopts a time-of-flight method to perform non-contact distance measurement, so that the TOF camera technology is one of a plurality of optical three-dimensional measurement technologies. The basic principle of TOF camera technology is: the light reflected by the object emitted by the active light source (such as modulated infrared light) is captured by the TOF camera, the distance between the object and the TOF camera is further calculated by calculating the time difference or phase difference between the reflected light and the emitted light, and the TOF camera captures the gray scale information while acquiring the measured depth information of the object, wherein the gray scale information is represented by the amplitude value (i.e. the measured amplitude value) of the reflected light. However, due to its own characteristics and imaging conditions, there are also external environment interferences, for example, the accuracy of the TOF camera is easily affected by the distance between the object to be photographed and the TOF camera and the intensity of the light reflected by the object to be photographed to the sensor, so that data acquired by the TOF camera usually has a certain error, and therefore the TOF camera needs to be calibrated.
Disclosure of Invention
The invention aims to provide a TOF camera calibration method and a TOF camera calibration system, which can ensure the accuracy and precision of calibration results of the TOF camera.
In order to solve the above problem, the present invention provides a TOF camera calibration method, including the following steps:
step S1: acquiring first actual depth information, first measurement depth information and first measurement gray scale information between a first shot object and a TOF camera, and acquiring first exposure time of the TOF camera;
step S2: constructing a first fitting model, a second fitting model and a third fitting model according to the first actual depth information, the first measured gray scale information and the first exposure time;
step S3: obtaining second actual depth information, second measured depth information and second measured gray scale information between a second shot object and the TOF camera, and simultaneously obtaining second exposure time of the TOF camera;
step S4: correcting swing errors caused by different depths of the second shot object by using the second measured depth information and according to the first fitting model by taking the second actual depth information as reference; and
step S5: and correcting depth errors caused by different reflection conditions of the second shot object according to the second fitting model and the third fitting model by using the second measured depth information, the second exposure time and the second measured gray scale information, so as to obtain calibrated measured depth information.
Optionally, step S2 includes:
constructing the first fitting model according to the first actual depth information and the first measured depth information;
constructing the second fitting model according to the first exposure time and the first measurement gray scale information; and
and constructing the third fitting model according to the second fitting model and the first measurement depth information.
Further, the first measured depth information includes a first measured distance between the first subject and the TOF camera, the first measured grayscale information includes a first measured amplitude, and the first actual depth information includes a first actual distance between the first subject and the TOF camera.
Further, the first fitting model is:
Correction1＝f(d)；
wherein, Correction1 is a Correction value after the wobble error is corrected; d is the measured distance.
Further, the second fitting model is:
NA＝Amplitude/e；
wherein, the Amplitude is the measured Amplitude; e is the exposure time.
Further, the third fitting model is:
Correction2＝f‘(d，NA)；
wherein, Correction2 is a corrected value of depth error caused by reflection condition; NA is a fitting result of the second fitting model; d is the measured distance.
Optionally, the second measured depth information includes a second measured distance between the second object and the TOF camera, the second measured grayscale information includes a second measured amplitude value, and the second actual depth information includes a second actual distance between the second object and the TOF camera.
Further, in step S4, with the second actual distance as a reference, the collected second measured distance is substituted into the first fitting model to correct the swing error caused by the difference in depth of the second object, so as to obtain the second measured depth information after preliminary calibration.
Further, in step S5, the collected second exposure time and the second measured amplitude are substituted into the second fitting model, and then the second fitting model and the second measured distance are substituted into the third fitting model to correct the depth error caused by the different reflection conditions of the second object, so as to obtain the calibrated second measured depth information.
On the other hand, the invention also provides a TOF camera calibration system which comprises a setting unit, a measuring and calculating unit, a swing correcting unit and a reflection correcting unit,
the setting unit is used for setting exposure time parameters of the TOF camera;
the measuring and calculating unit is used for calculating and acquiring first measurement depth information and first measurement gray scale information between a first shot object and the TOF camera in first exposure time, and calculating and acquiring second measurement depth information and second measurement gray scale information between a second shot object and the TOF camera in second exposure time;
the swing correction unit is used for setting a first fitting model, and correcting swing errors caused by different depths of the second shot object through the first fitting model by using the second measured depth information and second actual depth information between the second shot object and the TOF camera; and
the reflection correction unit is configured to set a second fitting model and a third fitting model, and correct a depth error caused by a difference in reflection conditions of the second object through the second fitting model and the third fitting model by using the second measured depth information, the second exposure time, and the second measured grayscale information.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a TOF camera calibration method and a TOF camera calibration system, wherein the TOF camera calibration method comprises the following steps: acquiring first actual depth information, first measurement depth information and first measurement gray scale information between a first shot object and a TOF camera, and acquiring first exposure time of the TOF camera; constructing a first fitting model, a second fitting model and a third fitting model according to the first actual depth information, the first measured gray scale information and the first exposure time; obtaining second actual depth information, second measured depth information and second measured gray scale information between a second shot object and the TOF camera, and simultaneously obtaining second exposure time of the TOF camera; correcting swing errors caused by different depths of the second shot object by using the second measured depth information and according to the first fitting model by taking the second actual depth information as reference; and correcting depth errors caused by different reflection conditions of the second shot object according to the second fitting model and the third fitting model by using the second measurement depth information, the second exposure time and the second measurement gray scale information to obtain calibrated measurement depth information, so that the method can be suitable for calibration of different exposure times, different shot objects and different distances between the shot objects and the TOF camera, and can ensure the accuracy and precision of a calibration result of the TOF camera.
Drawings
FIG. 1 is a flow chart of a TOF camera calibration method;
FIG. 2a is a graph showing the relationship between the measurement amplitude and the exposure time when a pure color paper with a gray scale of 250 is used as a subject;
FIG. 2b is a compensation curve graph of the same subject at different exposure times;
FIG. 3 is a flowchart of a TOF camera calibration method according to an embodiment of the present disclosure;
FIG. 4 is a graph of compensation curves of a plurality of solid color papers with different gray scales according to an embodiment of the present invention;
FIG. 5a is a diagram showing the relationship between the measured amplitude and the exposure time when two pure color papers with different gray scales are used as the object to be photographed according to an embodiment of the present invention;
fig. 5b is a graph showing the relationship between the measured amplitude and the test distance when two pure color papers with different gray scales are used as the object according to the embodiment of the present invention.
Detailed Description
As described in the background, since the accuracy of the TOF camera is easily affected by different distances between the subject and the TOF camera and the intensity of light reflected by the subject to the sensor, the data acquired by the TOF camera usually has a certain error, and therefore the TOF camera needs to be calibrated. The intensity of the light reflected by the subject to the sensor is typically characterized by a measured amplitude.
Fig. 1 is a flowchart of a TOF camera calibration method. As shown in FIG. 1, the influence of different distances between the object and the TOF camera and the intensity of light reflected by the object to the sensor is reduced by the current TOF calibration method.
The current TOF calibration method comprises the following steps:
firstly, first initial real depth information, first initial measured depth information and first initial measured gray scale information between a first initial shot object and a TOF camera are obtained, wherein the exposure time of the TOF camera is a preset exposure time, the first initial measured depth information comprises a first initial measured distance between the first initial shot object and the TOF camera, the first initial real depth information comprises a first initial real distance between the first initial shot object and the TOF camera, and the first initial measured gray scale information comprises a first initial measured amplitude value.
And then, with the first initial real depth information as a reference, constructing a first model according to the first initial measurement depth information, and constructing a second model according to the exposure time, the first initial measurement depth information and the first initial measurement gray scale information.
Specifically, the first model is: correction ═ f (d);
the second model is: (ii) Amplitude ═ g (e, v, d);
wherein, Correction is a corrected value after the depth error is corrected; d is the measurement distance, and amplitude is the measurement amplitude; e is the exposure time; v is a variable relating to the reflection of the subject.
Then, second initial measured depth information (i.e., a second initial measured distance) and second initial measured gray scale information (i.e., a second initial measured amplitude value) between a second initial subject and the TOF camera are obtained by the TOF camera, and second initial actual depth information between the second initial subject and the TOF camera is also obtained.
Then, with the second initial actual depth information as a reference, a wiggling correction unit corrects a wiggling error of the object caused by a difference in depth from the TOF camera according to the model by using the second initial measured depth information (i.e., performs wiggling correction).
Then, the reflection state correction unit corrects a depth error caused by different intensities (namely, reflection states) of light reflected to the sensor by the two pairs of shot objects according to the model by using the exposure time, the second initial measurement depth information and the second initial measurement gray scale information, so that calibrated second initial measurement depth information is obtained.
Fig. 2a is a graph showing the relationship between the exposure time and the measured amplitude when a solid color paper with a gray scale of 250 is used as a subject. As shown in fig. 2a, a1, a2 and a3 are the relationship between the measured amplitude and the exposure time of the same subject, respectively, and it can be seen that when the exposure time is different, the measured amplitude deviation is large, that is, the measured amplitude varies greatly with the exposure time.
Fig. 2b is a compensation curve chart of the same subject under different exposure times. As shown in fig. 2b, the compensation curves of the measured depth information of the same subject at different exposure times almost overlap, that is, the depth error hardly varies with the change of the exposure time, i.e., the change of the depth error with the exposure time almost remains unchanged. As can be seen from fig. 2a-2b, the same measured amplitude may correspond to a significantly different compensation value due to the exposure time.
Meanwhile, as shown in the following table one and the following table two, the gray scale of the subject 1 itself is 60, the gray scale of the subject 2 itself is 90, the gray scale of the subject 3 itself is 150, the gray scale of the subject 4 itself is 195, the gray scale of the subject 5 itself is 250, the distance between the subject of table one and the TOF camera is 1.43m, and the distance between the subject of table two and the TOF camera is 2.32 m. The first table and the second table respectively compensate the measured depth information of the TOF camera with the exposure time of 800 mu s and 500 mu s by using a fitting model constructed when the exposure time is 1900 mu s, wherein the difference between the depth error of the calibrated measured depth information corresponding to the exposure time of 1900 mu s and the depth error of the calibrated measured depth information corresponding to the exposure time of 800 mu s is very large, and similarly, the difference between the depth error of the calibrated measured depth information corresponding to the exposure time of 1900 mu s and the depth error of the calibrated measured depth information corresponding to the exposure time of 500 mu s is very large.
Depth error (unit: mm) of calibrated measurement depth
Depth error (unit: mm) of calibrated measurement depth
Watch two
This means that the fitting model constructed in the prior art cannot be adapted to applications with different exposure times.
Based on the analysis, the invention provides a TOF camera calibration method and a TOF camera calibration system, wherein the TOF camera calibration method comprises the following steps: acquiring first actual depth information, first measurement depth information and first measurement gray scale information between a first shot object and a TOF camera, and acquiring first exposure time of the TOF camera; constructing a first fitting model, a second fitting model and a third fitting model according to the first actual depth information, the first measured gray scale information and the first exposure time; obtaining second actual depth information, second measured depth information and second measured gray scale information between a second shot object and the TOF camera, and simultaneously obtaining second exposure time of the TOF camera; correcting swing errors caused by different depths of the second shot object by using the second measured depth information and according to the first fitting model by taking the second actual depth information as reference; and correcting depth errors caused by different reflection conditions of the second shot object according to the second fitting model and the third fitting model by using the second measurement depth information, the second exposure time and the second measurement gray scale information to obtain calibrated measurement depth information, so that the method is suitable for calibration of different exposure times, different shot objects and different distances between the shot objects and the TOF camera, and ensures the accuracy and precision of a calibration result of the TOF camera.
A TOF camera calibration method and system of the present invention will be described in further detail below. The present invention will now be described in more detail with reference to the accompanying drawings, in which preferred embodiments of the invention are shown, it being understood that one skilled in the art may modify the invention herein described while still achieving the advantageous effects of the invention. Accordingly, the following description should be construed as broadly as possible to those skilled in the art and not as limiting the invention.
In the interest of clarity, not all features of an actual implementation are described. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific details must be set forth in order to achieve the developer's specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art.
In order to make the objects and features of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. It is to be noted that the drawings are in a very simplified form and are all used in a non-precise ratio for the purpose of facilitating and distinctly aiding in the description of the embodiments of the invention.
Fig. 3 is a flowchart of a TOF camera calibration method according to the embodiment. As shown in fig. 3, the present embodiment provides a TOF camera calibration method, including the following steps:
step S1: acquiring first actual depth information, first measurement depth information and first measurement gray scale information between a first shot object and a TOF camera, and acquiring first exposure time of the TOF camera;
step S2: constructing a first fitting model, a second fitting model and a third fitting model according to the first actual depth information, the first measured gray scale information and the first exposure time;
step S3: obtaining second actual depth information, second measured depth information and second measured gray scale information between a second shot object and the TOF camera, and simultaneously obtaining second exposure time of the TOF camera;
step S4: correcting swing errors caused by different depths of the second shot object by using the second measured depth information and according to the first fitting model by taking the second actual depth information as reference; and
step S5: and correcting depth errors caused by different reflection conditions of the second shot object according to the second fitting model and the third fitting model by using the second measured depth information, the second exposure time and the second measured gray scale information, so as to obtain calibrated measured depth information.
The TOF camera calibration method of the present embodiment is described in detail below with reference to fig. 3-4 and fig. 5a-5 b.
Step S1 is performed first, and first actual depth information, first measured depth information, and first measured grayscale information between the first subject and the TOF camera are acquired, and a first exposure time of the TOF camera is also acquired.
Wherein the first measured depth information comprises a first measured distance between the first subject and the TOF camera, the first measured grayscale information comprises a first measured amplitude value, and the first actual depth information comprises a first actual distance between the first subject and the TOF camera.
In this embodiment, the more data corresponding to each parameter (the first actual depth information, the first measured depth information, and the first measured gray scale information) of the TOF camera at the first exposure time is acquired, the more stable the first fitting model, the second fitting model, and the third fitting model constructed in step S2 is, and the better the robustness is.
Next, step S2 is executed to construct a first fitting model, a second fitting model and a third fitting model according to the first actual depth information, the first measured gray scale information and the first exposure time.
The method specifically comprises the following steps:
step S21, constructing a first fitting model according to the first actual depth information and the first measured depth information.
The first fitting model is: correction1 ═ f (d);
wherein, Correction1 is a Correction value after the wobble error is corrected; d is the measured distance.
And step S22, constructing a second fitting model according to the first exposure time and the first measured gray scale information.
FIG. 4 is a graph showing compensation curves of a plurality of solid color papers with different gray levels according to the present embodiment. As shown in fig. 4, the compensation curves of the solid color papers with different gray scales are obviously different, and it is known that the main source of the depth error is the depth error caused by the reflection condition of the second object.
Fig. 5a is a graph showing the relationship between the measured amplitude and the exposure time when two pure color sheets with different gray scales are used as the object of the present embodiment. As shown in fig. 5a, b1, b2, b3, b4 and b5 are measured amplitude values and exposure times of five solid color papers with a gray scale of 150, and c1, c2, c3, c4 and b5 are measured amplitude values and exposure times of five solid color papers with a gray scale of 250, wherein the correlation coefficient of the measured amplitude values and the exposure times R1 is more than 0.9999. It can be seen that in most cases, the measured amplitude is proportional to the exposure time.
Fig. 5b is a graph showing the relationship between the measured amplitude and the test distance when two pure color papers with different gray scales are used as the object of the present embodiment. As shown in fig. 5b, d1, d2, d3 and d4 are measured amplitudes of four solid color sheets with a gray scale of 150 in relation to exposure time, and e1, e2, e3 and e4 are measured amplitudes of four solid color sheets with a gray scale of 250 in relation to exposure time, and at this time, the correlation coefficient R2 of the reciprocal (1/d) of the measured distance and the square root of the measured amplitude is > 0.9985. It is known that the measured amplitude is inversely proportional to the square of the measured distance. Based on this, we can construct a second fitted model independent of exposure time.
The second fitting model is: NA is Amplitude/e;
wherein, the Amplitude is the measured Amplitude; e is the exposure time.
In detail, the process of constructing the second fitting model includes:
Amplitude＝g(e，v，d)；
Amplitude＝e*g“(v)/d 2 ；
g“(v)＝Amplitude*d 2 /e；
NA＝Amplitude/e；
wherein, Amplitude is the measured Amplitude; e is the exposure time; d is a measurement distance; v is a variable relating to the reflection of the subject.
And step S23, constructing a third fitting model according to the second fitting model and the first measurement depth information.
The third fitting model is: correction2 ═ f' (d, NA);
wherein, Correction2 is a corrected value after depth error Correction; NA is the fitting result of the second fitting model; d is the measured distance.
In detail, the process of constructing the third fitting model includes:
Correction2＝f(d，v)；
Correction2＝f‘(d，g“(v))；
NA＝Amplitude/e；
Correction2＝f‘(d，NA)；
wherein, Correction2 is a corrected value after reflection condition Correction; NA is the fitting result of the second fitting model; d is a measurement distance; v is a variable relating to the reflection of the subject.
Step S3 is then performed to obtain second actual depth information, second measured depth information, and second measured grayscale information between a second subject and the TOF camera, while also obtaining a second exposure time of the TOF camera. This step is used for data acquisition to carry out depth error correction on the data acquired.
Wherein the second measured depth information comprises a second measured distance between the second object and the TOF camera, the second measured grayscale information comprises a second measured amplitude value, and the second actual depth information comprises a second actual distance between the second object and the TOF camera.
Next, step S4 is executed to correct the wobbling error caused by the difference in depth of the second object according to the first fitting model using the second measurement information with the second actual depth information as a reference.
In this step, the second actual distance is taken as a reference, and the collected second measured distance is brought into a first fitting model to correct swing errors caused by different depths of the second shot object, so that second measured depth information after preliminary calibration is obtained, and further the depth error of the second measured depth information is preliminarily reduced.
And step S5 is executed to correct the depth error caused by the difference in reflection of the second object according to the second fitting model and the third fitting model by using the second measured depth information, the second exposure time, and the second measured gray scale information, so as to obtain the calibrated measured depth information.
In this step, the collected second exposure time and second measurement amplitude are brought into the second fitting model, and then the second fitting model and the second measurement distance are brought into the third fitting model to correct the depth error caused by the different reflection conditions of the second object, that is, further correct the depth information after the swing correction, so as to obtain the calibrated second measurement depth information with high accuracy and precision.
As shown in tables three to six below, the first fitting model, the second fitting model and the third fitting model were constructed in each of tables three to six with an exposure time of 1900 μ s. The gray scale of the subject 1 is 60, the gray scale of the subject 2 is 90, the gray scale of the subject 3 is 150, the gray scale of the subject 4 is 195, the gray scale of the subject 5 is 250, the distances between the subjects in table three and table five and the TOF camera are 1.43m, the distances between the subjects in table four and table six and the TOF camera are 2.32m, the depth errors of the measured depths (i.e., the measured distances) obtained by calibrating the mixed measurement data acquired during different exposure times (i.e., the mixed exposure times) are both table four and table six, the depth errors of the calibrated measured depths corresponding to the exposure times of 1900 μ s and 800 μ s are table five, and the depth errors of the calibrated measured depths corresponding to the exposure times of 1900 μ s and 500 μ s are table seven. It can be known that the relative error after the depth error compensation performed by the first fitting model, the second fitting model and the third fitting model constructed by the TOF camera calibration method of the present embodiment is very small, for example, the relative error is less than 1%.
Watch III
Watch four
Watch five
Watch six
The embodiment further provides a TOF camera calibration system, which includes a setting unit, a measuring and calculating unit, a wiggling (swinging) correcting unit, and a reflection correcting unit, where the setting unit is configured to set parameters such as exposure time of the TOF camera. The measuring and calculating unit is used for calculating and acquiring the measured depth information and the measured gray scale information between a shot object and the TOF camera, for example, calculating and acquiring first measured depth information and first measured gray scale information between a first shot object and the TOF camera, and calculating and acquiring second measured depth information and second measured gray scale information between a second shot object and the TOF camera. The swing correction unit is used for setting the first fitting model, and correcting swing errors caused by different depths of the second shot object through the first fitting model by using the second actual depth information and the second measured depth information. The reflection correction unit is used for setting a second fitting model and a third fitting model, and correcting depth errors caused by different reflection situations of the second shot object through the second fitting model and the third fitting model by using the second measured depth information, the second exposure time and the second measured gray scale information.
In summary, the present invention provides a TOF camera calibration method and system, where the TOF camera calibration method includes the following steps: acquiring first actual depth information, first measurement depth information and first measurement gray scale information between a first shot object and a TOF camera, and acquiring first exposure time of the TOF camera; constructing a first fitting model, a second fitting model and a third fitting model according to the first actual depth information, the first measured gray scale information and the first exposure time; obtaining second actual depth information, second measured depth information and second measured gray scale information between a second shot object and the TOF camera, and simultaneously obtaining second exposure time of the TOF camera; correcting swing errors caused by different depths of the second shot object by using the second measured depth information and according to the first fitting model by taking the second actual depth information as reference; and correcting depth errors caused by different reflection conditions of the second shot object according to the second fitting model and the third fitting model by using the second measurement depth information, the second exposure time and the second measurement gray scale information to obtain calibrated measurement depth information, so that the method is suitable for calibration of different exposure times, different shot objects and different distances between the shot objects and the TOF camera, and ensures the accuracy and precision of a calibration result of the TOF camera.
In addition, unless otherwise specified or indicated, the description of the terms "first" and "second" in the specification is only used for distinguishing various components, elements, steps and the like in the specification, and is not used for representing logical relationships or sequential relationships among the various components, elements, steps and the like.
It is to be understood that while the present invention has been described in conjunction with the preferred embodiments thereof, it is not intended to limit the invention to those embodiments. It will be apparent to those skilled in the art from this disclosure that many changes and modifications can be made, or equivalents modified, in the embodiments of the invention without departing from the scope of the invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the protection of the technical solution of the present invention, unless the contents of the technical solution of the present invention are departed.
Claims (10)
1. A TOF camera calibration method is characterized by comprising the following steps:
step S1: acquiring first actual depth information, first measurement depth information and first measurement gray scale information between a first shot object and a TOF camera, and acquiring first exposure time of the TOF camera;
step S2: constructing a first fitting model, a second fitting model and a third fitting model according to the first actual depth information, the first measured gray scale information and the first exposure time;
step S3: obtaining second actual depth information, second measured depth information and second measured gray scale information between a second shot object and the TOF camera, and simultaneously obtaining second exposure time of the TOF camera;
step S4: correcting swing errors caused by different depths of the second shot object by using the second measured depth information and according to the first fitting model by taking the second actual depth information as reference; and
step S5: and correcting depth errors caused by different reflection conditions of the second shot object according to the second fitting model and the third fitting model by using the second measured depth information, the second exposure time and the second measured gray scale information, so as to obtain calibrated measured depth information.
2. The TOF camera calibration method according to claim 1, wherein step S2 includes:
constructing the first fitting model according to the first actual depth information and the first measured depth information;
constructing the second fitting model according to the first exposure time and the first measurement gray scale information; and
and constructing the third fitting model according to the second fitting model and the first measurement depth information.
3. The TOF camera calibration method of claim 2 wherein the first measured depth information comprises a first measured distance between the first subject and the TOF camera, the first measured grayscale information comprises a first measured amplitude value, and the first actual depth information comprises a first actual distance between the first subject and the TOF camera.
4. A TOF camera calibration method according to claim 3 wherein the first fitted model is:
Correction1＝f(d)；
wherein, Correction1 is a Correction value after the wobble error is corrected; d is the measured distance.
5. A TOF camera calibration method according to claim 3 wherein the second fitted model is:
NA＝Amplitude/e；
wherein NA is a fitting result of the second fitting model; the Amplitude is measured; e is the exposure time.
6. A TOF camera calibration method according to claim 3 wherein the third fitted model is:
Correction2＝f‘(d，NA)；
wherein, Correction2 is a corrected value after depth error Correction; NA is the fitting result of the second fitting model; d is the measured distance.
7. The TOF camera calibration method of claim 1, wherein the second measured depth information includes a second measured distance between the second subject and the TOF camera, the second measured grayscale information includes a second measured amplitude, and the second actual depth information includes a second actual distance between the second subject and the TOF camera.
8. The TOF camera calibration method according to claim 7, wherein in step S4, with the second actual distance as a reference, the acquired second measured distance is substituted into the first fitting model to correct the wobble error caused by the difference in depth of the second object, so as to obtain the second measured depth information after preliminary calibration.
9. The TOF camera calibration method according to claim 7, wherein in step S5, the collected second exposure time and the second measured amplitude are substituted into the second fitting model, and then the second fitting model and the second measured distance are substituted into the third fitting model to correct the depth error caused by the different reflection conditions of the second object, so as to obtain the calibrated second measured depth information.
10. A TOF camera calibration system is characterized by comprising a setting unit, a measuring and calculating unit, a swing correcting unit and a reflection correcting unit,
the setting unit is used for setting exposure time parameters of the TOF camera;
the measuring and calculating unit is used for calculating and acquiring first measurement depth information and first measurement gray scale information between a first shot object and the TOF camera in first exposure time, and calculating and acquiring second measurement depth information and second measurement gray scale information between a second shot object and the TOF camera in second exposure time;
the swing correction unit is used for setting a first fitting model, and correcting swing errors caused by different depths of the second shot object through the first fitting model by using the second measured depth information and second actual depth information between the second shot object and the TOF camera; and
the reflection correction unit is configured to set a second fitting model and a third fitting model, and correct a depth error caused by a difference in reflection conditions of the second object through the second fitting model and the third fitting model by using the second measured depth information, the second exposure time, and the second measured grayscale information.
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