Depth Camera

Abstract

The present invention provides a depth camera, comprising: a light projection module, used to project a light beam to a target object in a scene; a light receiving module, used to receive a light signal formed by the light beam reflected by the target object through at least four receiving windows, so as to collect at least a first electrical signal, a second electrical signal, a third electrical signal and a fourth electrical signal at each pixel point according to a preset equally spaced phase difference; a control module, used to determine a proportional factor according to the value sum of the first electrical signal and the third electrical signal and the value sum of the second electrical signal and the fourth electrical signal, and to determine whether the proportional factor is within a preset threshold interval, and when the proportional factor is within the preset proportional interval, the pixel point is determined to be motion blurred. The present invention can determine whether the pixel point has motion blur according to the proportional factor, realize quick detection of motion blur within a single-frequency frame and between dual-frequency frames, facilitate motion blur removal, and improve the display effect of the depth image.

Description

Technical Field

[0001] The present invention relates to a TOF camera, and in particular to a depth camera. Background Art

[0002] In recent years, 3D vision has been widely used in industries such as robotics, industrial production, intelligent logistics, medical care, autonomous driving, and secure payment. Among them, TOF cameras, as a device that can output depth maps, have also been widely studied. The principle of TOF cameras is to calculate the distance of the photographed object from the camera by calculating the phase difference between the emitted infrared light and the received infrared light. In order to improve the accuracy, four sine waves with different phases are usually used in the prior art to correlate with the received light to calculate the depth value. Furthermore, in order to increase the camera's ranging by 20%, two depth maps are usually calculated using two different frequencies of emitted infrared light, and a depth map with a larger range is obtained by dual-frequency fusion.

[0003] However, in practical applications, the movement of the object or the camera itself usually causes the correlation graphs of the four different phases at the same frequency to not match, and the depth graphs between the two frequencies to not match. This results in incorrect depth values ​​due to motion when calculating the depth using the four phases and performing dual-frequency fusion, resulting in motion blur.

[0004] As for the elimination of motion blur, due to the inconsistency between the imaging methods of TOF cameras and traditional RGB cameras, the methods used by traditional cameras to eliminate motion blur cannot be directly applied to TOF cameras. The current motion blur detection and removal methods for TOF cameras have their own drawbacks and cannot be used in most scenarios. In addition, there is currently no detection and removal of motion blur generated by dual-frequency fusion. Summary of the invention

[0005] In view of the defects in the prior art, an object of the present invention is to provide a depth camera.

[0006] The depth camera provided by the present invention includes the following modules:

[0007] A light projection module, used to project a light beam to a target object in the scene;

[0008] an optical receiving module, configured to receive, through at least four receiving windows, an optical signal formed after the light beam is reflected by the target object, so as to collect at least a first electrical signal, a second electrical signal, a third electrical signal and a fourth electrical signal at each pixel point according to a preset equally spaced phase difference;

[0009] A control module is used to determine a proportional factor based on the numerical value and ratio of the first electrical signal and the third electrical signal and the numerical value and ratio of the second electrical signal and the fourth electrical signal, and to determine whether the proportional factor is within a preset threshold range. When the proportional factor is within the preset proportional range, it is determined that the pixel is motion blurred.

[0010] Preferably, the light projection module comprises a light source, a light source driver and a light modulator;

[0011] The light source driver is connected to the light source and is used to drive the light source to emit light;

[0012] The light modulator is connected to the light source, and is used for modulating the light projected by the light source into a sinusoidal wave light beam and then projecting it toward the target object to be measured.

[0013] Preferably, the light receiving module comprises a lens, a filter and an image sensor arranged along the light path, and the image sensor is provided with at least four receiving windows;

[0014] The image sensor is used to receive the optical signal through at least four receiving windows; the at least four receiving windows are arranged in sequence at equal intervals in time sequence, and then generate the first electrical signal, the second electrical signal, the third electrical signal and the fourth electrical signal respectively according to the optical signal received by each receiving window.

[0015] Preferably, determining the scaling factor comprises the following steps:

[0016] Step M1: Calculate the sum of the values ​​of the first electrical signal and the third electrical signal, that is, Sum0+Sum 180 , the first electrical signal Sum0 represents an electrical signal with a phase angle of 0, and the third electrical signal Sum 180 Represents an electrical signal with a phase angle of 180;

[0017] Step M2: Calculate the sum of the values ​​of the second electrical signal and the fourth electrical signal, that is, Sum 90 +Sum 270 , the second electrical signal Sum 90 represents an electrical signal with a phase angle of 90, and the third electrical signal Sum 270 Represents an electrical signal with a phase angle of 270;

[0018] Step M3: Generate a proportional factor ratio, where ratio = (Sum0 + Sum 180 ) / (Sum 90 +Sum 270 ).

[0019] Preferably, determining the scaling factor comprises the following steps:

[0020] Step N1: Calculate the sum of the values ​​of the first electrical signal A, the first electrical signal B, the third electrical signal A and the third electrical signal B, that is, The first electrical signal Indicates that the electrical signal with a phase angle of 0 formed by receiving the first light beam, the third electrical signal Indicates that an electrical signal with a phase angle of 180 is received by the first light beam, wherein the first electrical signal Indicates that the phase angle of the second light beam is 0, and the third electric signal Indicates that the electrical signal with a phase angle of 180 formed by receiving the second light beam, 75Mhz indicates the frequency of the first light beam, and 100Mhz indicates the frequency of the second light beam;

[0021] Step N2: Calculate the sum of the values ​​of the second electrical signal A, the fourth electrical signal A, the second electrical signal B and the fourth electrical signal B, that is, The second electrical signal Indicates that the electrical signal with a phase angle of 90° formed by receiving the first light beam, the fourth electrical signal Indicates that the phase angle of the first light beam is 270°, and the second light beam is Indicates that the electrical signal with a phase angle of 90° formed by receiving the second light beam, the fourth electrical signal Indicates that the electrical signal with a phase angle of 270 formed by receiving the second light beam;

[0022] Step N3: Generate a scaling factor ratio,

[0023] in,

[0024] Preferably, when removing the motion blur, the following steps are included:

[0025] Step S1: when a pixel point has motion blur, the pixel value of the pixel point is set to a first value, otherwise it is set to a second value, and a first binary image is generated;

[0026] Step S2: performing a dilation operation on the first binary image to remove isolated pixels, thereby generating a second binary image;

[0027] Step S3: Acquire a depth image, align the depth image with the second binary image at the pixel level, and set the depth values ​​of the pixel points with the first value in the second binary image and the depth values ​​of the corresponding positions in the depth image to 0 to remove motion blur.

[0028] Preferably, each of the electrical signals is the sum of the electrical signal tapA and the electrical signal tapB;

[0029] The electrical signal tapA is collected through the first capacitor, and the electrical signal tapB is collected through the second capacitor; the phase difference between the signal receiving time windows of the first capacitor and the second capacitor is 180°.

[0030] Preferably, the first electrical signal A is an electrical signal with a phase angle of 0, the second electrical signal A is an electrical signal with a phase angle of 90, the third electrical signal A is an electrical signal with a phase angle of 180, and the fourth electrical signal A is an electrical signal with a phase angle of 270. The first electrical signal B is an electrical signal with a phase angle of 0, the second electrical signal B is an electrical signal with a phase angle of 90, the third electrical signal B is an electrical signal with a phase angle of 180, and the fourth electrical signal B is an electrical signal with a phase angle of 270.

[0031] Preferably, the first electrical signal is an electrical signal with a phase angle of 0, the second electrical signal is an electrical signal with a phase angle of 90, the third electrical signal is an electrical signal with a phase angle of 180, and the fourth electrical signal is an electrical signal with a phase angle of 270.

[0032] Preferably, the electrical signal tapB is an inverted signal of the electrical signal tapA, and the electrical signal tapB and the electrical signal tapA are voltage signals, charge quantities or pixel values.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] In the present invention, the optical receiving module collects four electrical signals at equal intervals and phase differences at a pixel point, and the control module determines a proportional factor by the ratio of the sum of the values ​​of the first electrical signal and the third electrical signal to the sum of the values ​​of the second electrical signal and the fourth electrical signal. According to the proportional factor, it is determined whether there is motion blur at the pixel point, thereby realizing quick detection of motion blur within a single-frequency frame and between dual-frequency frames, facilitating motion blur removal, and improving the display effect of the depth image.

[0035] In the present invention, each of the electrical signals is the sum of the electrical signal tapA and the electrical signal tapB. The electrical signals tapA and tapB are electrical signals collected by two different capacitors at the same time. Compared with using only tapA or tapB, the accuracy of motion blur can be improved, and the robustness of the present invention to the temporal noise of a single capacitor is improved, thereby reducing the possibility of misjudgment and missed judgment, and can ensure that the motion blur area can be effectively identified in more scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings in the following descriptions are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without creative work. By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, purposes and advantages of the present invention will become more obvious:

[0037] Figure 1 Schematic diagram of a module of a depth camera according to an embodiment of the present invention;

[0038] Figure 2 Schematic diagram of a light projection module in an embodiment of the present invention;

[0039] Figure 3 Schematic diagram of a light receiving module in an embodiment of the present invention;

[0040] Figure 4 A flow chart of the steps of calculating the proportional factor in an embodiment of the present invention;

[0041] Figure 5 A flowchart of the steps of calculating the proportional factor in a variation of the present invention; and

[0042] Figure 6 The figure is a flow chart of the steps of removing motion blur in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several variations and improvements may be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0044] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein, for example, can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0045] The technical solution of the present invention is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0046] The depth camera provided by the present invention is intended to solve the problems existing in the prior art.

[0047] The following specific embodiments are used to describe in detail the technical solutions of the present invention and how the technical solutions of the present application solve the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present invention will be described below in conjunction with the accompanying drawings.

[0048] Figure 1 FIG. 1 is a schematic diagram of a module of a depth camera according to an embodiment of the present invention. Figure 1 As shown, the depth camera provided by the present invention includes the following modules:

[0049] A light projection module, used to project a light beam to a target object in the scene;

[0050] an optical receiving module, configured to receive, through at least four receiving windows, an optical signal formed after the light beam is reflected by the target object, so as to collect at least a first electrical signal, a second electrical signal, a third electrical signal and a fourth electrical signal at each pixel point according to a preset equally spaced phase difference;

[0051] A control module is used to determine a proportional factor based on the numerical value and ratio of the first electrical signal and the third electrical signal and the numerical value and ratio of the second electrical signal and the fourth electrical signal, and to determine whether the proportional factor is within a preset threshold range. When the proportional factor is within the preset proportional range, it is determined that the pixel is motion blurred.

[0052] In an embodiment of the present invention, the depth camera in the present invention is a TOF camera applied to 2tap, 4 phases. Each of the electrical signals is the sum of the electrical signal tapA and the electrical signal tapB;

[0053] The electrical signal tapA is collected through the first capacitor, and the electrical signal tapB is collected through the second capacitor; the phase difference between the signal receiving time windows of the first capacitor and the second capacitor is 180°.

[0054] In an embodiment of the present invention, the electrical signal tapB is an inverted signal of the electrical signal tapA, and the electrical signal tapB and the electrical signal tapA can be voltage signals, or can be charge amounts or pixel values. In the present invention, each of the electrical signals is the sum of the electrical signal tapA and the electrical signal tapB, and the electrical signals tapA and tapB are electrical signals collected by two different capacitors at the same time. Compared with using only tapA or tapB, the accuracy of motion blur can be improved, and the robustness of the present invention to the temporal noise of a single capacitor is improved, thereby reducing the possibility of misjudgment and missed judgment, and can ensure effective identification of motion blur areas in more scenarios.

[0055] In the embodiment of the present invention, the threshold interval may be set to [0, 0.98)U(1.02, +∞].

[0056] Figure 2 FIG. 1 is a schematic diagram of a light projection module according to an embodiment of the present invention. Figure 2 As shown, the light projection module includes a light source, a light source driver and a light modulator;

[0057] The light source driver is connected to the light source and is used to drive the light source to emit light;

[0058] The light modulator is connected to the light source, and is used for modulating the light projected by the light source into a sinusoidal wave light beam and then projecting it toward the target object to be measured.

[0059] Figure 3 FIG. 1 is a schematic diagram of a light receiving module in an embodiment of the present invention. Figure 3 As shown, the light receiving module includes a lens, a filter and an image sensor arranged along the light path, and the image sensor is provided with at least four receiving windows;

[0060] The image sensor is used to receive the optical signal through at least four receiving windows; the at least four receiving windows are arranged in sequence at equal intervals in time sequence, and then generate the first electrical signal, the second electrical signal, the third electrical signal and the fourth electrical signal respectively according to the optical signal received by each receiving window.

[0061] In an embodiment of the present invention, when the depth camera provided by the present invention is used, a light beam is projected toward a target object through a light projector module, and the light beam is a modulated sinusoidal wave beam; the light receiving module receives the light beam reflected by the target object, and each detector in the imaging array generates an electrical signal according to the received light signal, and collects a first electrical signal, a second electrical signal, a third electrical signal, and a fourth electrical signal at equally spaced phases of 90°.

[0062] The image sensor is used to receive at least the optical signal through at least four receiving windows; the at least four receiving windows are arranged sequentially in time sequence, and then each of the electrical signals is generated according to the optical signal received by each of the receiving windows.

[0063] In the embodiment of the present invention, the first electrical signal is an electrical signal with a phase angle of 0, the second electrical signal is an electrical signal with a phase angle of 90, the third electrical signal is an electrical signal with a phase angle of 180, and the fourth electrical signal is an electrical signal with a phase angle of 270.

[0064] In a variation of the present invention, when the depth camera provided by the present invention is used, a first light beam of a first frequency and a second light beam of a second frequency are projected toward a target object through a light projector module, and the first light beam and the second light beam are modulated sinusoidal wave light beams; the first light beam and the second light beam reflected by the target object are received through the light receiving module, and an electrical signal is generated according to the received light signal by each detector in the imaging array, and a first electrical signal A, a second electrical signal A, a third electrical signal A and a fourth electrical signal A are collected with an equal phase interval of 90° for the electrical signal formed by receiving the first light beam, and a first electrical signal B, a second electrical signal B, a third electrical signal B and a fourth electrical signal B are collected with an equal phase interval of 90° for the electrical signal formed by receiving the second light beam.

[0065] In the embodiment of the present invention, the first electrical signal A is an electrical signal with a phase angle of 0, the second electrical signal A is an electrical signal with a phase angle of 90, the third electrical signal A is an electrical signal with a phase angle of 180, and the fourth electrical signal A is an electrical signal with a phase angle of 270. The first electrical signal B is an electrical signal with a phase angle of 0, the second electrical signal B is an electrical signal with a phase angle of 90, the third electrical signal B is an electrical signal with a phase angle of 180, and the fourth electrical signal B is an electrical signal with a phase angle of 270.

[0066] Figure 4 FIG. 1 is a flow chart of steps for calculating the proportional factor in an embodiment of the present invention. Figure 4 As shown, determining the scale factor includes the following steps:

[0067] Step M1: Calculate the sum of the values ​​of the first electrical signal and the third electrical signal, that is, Sum0+Sum 180 , the first electrical signal Sum0 represents an electrical signal with a phase angle of 0, and the third electrical signal Sum 180 Represents an electrical signal with a phase angle of 180;

[0068] Step M2: Calculate the sum of the values ​​of the second electrical signal and the fourth electrical signal, that is, Sum 90 +Sum 270 , the second electrical signal Sum 90 represents an electrical signal with a phase angle of 90, and the third electrical signal Sum270 Represents an electrical signal with a phase angle of 270;

[0069] Step M3: Generate a proportional factor ratio, where ratio = (Sum0 + Sum 180 ) / (Sum 90 +Sum 270 ).

[0070] Figure 5 FIG. 1 is a flow chart of the steps of calculating the proportional factor in a modified example of the present invention, as shown in FIG. Figure 5 As shown, determining the scale factor includes the following steps:

[0071] Step N1: Calculate the sum of the values ​​of the first electrical signal A, the first electrical signal B, the third electrical signal A and the third electrical signal B, that is, The first electrical signal Indicates that the electrical signal with a phase angle of 0 formed by receiving the first light beam, the third electrical signal Indicates that an electrical signal with a phase angle of 180 is received by the first light beam, wherein the first electrical signal Indicates that the phase angle of the second light beam is 0, and the third electric signal Indicates that the electrical signal with a phase angle of 180 formed by receiving the second light beam, 75Mhz indicates the frequency of the first light beam, and 100Mhz indicates the frequency of the second light beam;

[0072] Step N2: Calculate the sum of the values ​​of the second electrical signal A, the fourth electrical signal A, the second electrical signal B and the fourth electrical signal B, that is, The second electrical signal Indicates that the electrical signal with a phase angle of 90° formed by receiving the first light beam, the fourth electrical signal Indicates that the phase angle of the first light beam is 270°, and the second light beam is Indicates that the electrical signal with a phase angle of 90° formed by receiving the second light beam, the fourth electrical signal Indicates that the electrical signal with a phase angle of 270 formed by receiving the second light beam;

[0073] Step N3: Generate a scaling factor ratio,

[0074] in,

[0075] In the embodiment of the present invention, the motion blur may also be judged according to |1-ratio|>ε1, and the value of ε1 may be set to 0.02.

[0076] Figure 6 FIG. 1 is a flow chart of the steps of removing motion blur in an embodiment of the present invention. Figure 6 As shown, the depth camera provided by the present invention, when removing the motion blur, includes the following steps:

[0077] Step S1: when a pixel point has motion blur, the pixel value of the pixel point is set to a first value, otherwise it is set to a second value, and a first binary image is generated;

[0078] Step S2: performing a dilation operation on the first binary image to remove isolated pixels, thereby generating a second binary image;

[0079] Step S3: Acquire a depth image, align the depth image with the second binary image at the pixel level, and set the depth values ​​of the pixel points with the first value in the second binary image and the depth values ​​of the corresponding positions in the depth image to 0 to remove motion blur.

[0080] In the embodiment of the present invention, the first value can be set to 255; the second value can be set to 0; the depth image is an infrared image generated by the TOF camera when collecting the first electrical signal, the second electrical signal, the third electrical signal and the fourth electrical signal. The expansion operation is specifically to enlarge each pixel so that adjacent pixels are connected.

[0081] In an embodiment of the present invention, the optical receiving module in the present invention collects four electrical signals with equal intervals of phase difference at a pixel point, and the control module determines a proportional factor through the ratio of the numerical value sum of the first electrical signal and the third electrical signal to the numerical value sum of the second electrical signal and the fourth electrical signal, and determines whether there is motion blur at the pixel point according to the proportional factor, thereby realizing quick detection of motion blur within a single-frequency frame and between dual-frequency frames, facilitating motion blur removal, and improving the display effect of the depth image; in the present invention, each of the electrical signals is the sum of the electrical signal tapA and the electrical signal tapB, and the electrical signals tapA and tapB are electrical signals collected by two different capacitors at the same time. Compared with using only tapA or tapB, the accuracy of motion blur can be improved, and the robustness of the present invention to the temporal noise of a single capacitor is improved, thereby reducing the possibility of misjudgment and missed judgment, and can ensure that the motion blur area can be effectively identified in more scenarios.

[0082] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the embodiments can be referred to each other. The above description of the disclosed embodiments enables professionals and technicians in this field to implement or use the present invention. Various modifications to these embodiments will be obvious to professionals and technicians in this field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown in this article, but will comply with the widest range consistent with the principles and novel features disclosed herein.

[0083] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A depth camera, characterized in that: Includes the following modules: A light projection module, used to project a light beam to a target object in the scene; an optical receiving module, configured to receive, through at least four receiving windows, an optical signal formed after the light beam is reflected by the target object, so as to collect at least a first electrical signal, a second electrical signal, a third electrical signal and a fourth electrical signal at each pixel point according to a preset equally spaced phase difference; a control module, configured to determine a proportional factor according to the sum of the values ​​of the first electrical signal and the third electrical signal and the sum of the values ​​of the second electrical signal and the fourth electrical signal, and determine whether the proportional factor is within a preset threshold interval, and when the proportional factor is within the preset proportional interval, determine that the pixel is motion blurred; Wherein, determining the scaling factor comprises the following steps: Step N1: Calculate the sum of the values ​​of the first electrical signal A, the first electrical signal B, the third electrical signal A and the third electrical signal B, that is, The first electrical signal Indicates that the electrical signal with a phase angle of 0 formed by receiving the first light beam, the third electrical signal Indicates that an electrical signal with a phase angle of 180 is received by the first light beam, wherein the first electrical signal Indicates that the phase angle of the second light beam is 0, and the third electric signal Indicates that the electrical signal with a phase angle of 180 formed by receiving the second light beam, 75Mhz indicates the frequency of the first light beam, and 100Mhz indicates the frequency of the second light beam; Step N2: Calculate the sum of the values ​​of the second electrical signal A, the fourth electrical signal A, the second electrical signal B and the fourth electrical signal B, that is, The second electrical signal Indicates that the electrical signal with a phase angle of 90° formed by receiving the first light beam, the fourth electrical signal Indicates that the phase angle of the first light beam is 270°, and the second light beam is Indicates that the electrical signal with a phase angle of 90° formed by receiving the second light beam, the fourth electrical signal Indicates that the electrical signal with a phase angle of 270 formed by receiving the second light beam; Step N3: Generate a scaling factor ratio, in, 2. The depth camera according to claim 1, characterized in that The light projection module includes a light source, a light source driver and a light modulator; The light source driver is connected to the light source and is used to drive the light source to emit light; The light modulator is connected to the light source, and is used for modulating the light projected by the light source into a sinusoidal wave light beam and then projecting it toward the target object to be measured.

3. The depth camera according to claim 1, characterized in that The light receiving module comprises a lens, a filter and an image sensor arranged along the light path, and the image sensor is provided with at least four receiving windows; The image sensor is used to receive the optical signal through at least four receiving windows; the at least four receiving windows are arranged in sequence at equal intervals in time sequence, and then generate the first electrical signal, the second electrical signal, the third electrical signal and the fourth electrical signal respectively according to the optical signal received by each receiving window.

4. The depth camera according to claim 1, characterized in that When removing the motion blur, the following steps are included: Step S1: when a pixel point has motion blur, the pixel value of the pixel point is set to a first value, otherwise it is set to a second value, and a first binary image is generated; Step S2: performing a dilation operation on the first binary image to remove isolated pixels, thereby generating a second binary image; Step S3: Acquire a depth image, align the depth image with the second binary image at the pixel level, and set the depth values ​​of the pixels in the second binary image whose pixel values ​​are the first value at the corresponding positions on the depth image to 0 to remove motion blur.

5. The depth camera according to claim 1, characterized in that: Each of the electrical signals is the sum of the electrical signal tapA and the electrical signal tapB; The electrical signal tapA is collected through the first capacitor, and the electrical signal tapB is collected through the second capacitor; the phase difference between the signal receiving time windows of the first capacitor and the second capacitor is 180°.

6. The depth camera according to claim 5, characterized in that: The electrical signal tapB is an inverted signal of the electrical signal tapA, and the electrical signal tapB and the electrical signal tapA are voltage signals, charge amounts, or pixel values.

Images