Complementary metal oxide semiconductor (CMOS) image sensor roller shutter delay test assembly, method, device and system

Abstract

The invention discloses a CMOS image sensor roller shutter delay test assembly, method, device and system, the test assembly comprises a test cylinder, the side wall of the test cylinder is externally provided with a plurality of test strips arranged along the axial direction of the test cylinder, the distance between two adjacent test strips is equal, and the distance between the test strips is equal to the distance between two adjacent test strips; the color of the test strip area is different from that of an area between two adjacent test strips; and the driving structure is used for driving the testing cylinder to rotate around the rotating shaft at a constant speed. According to the image of the test strip obtained by the CMOS image sensor, the test of the exposure asynchronism of each pixel in a single frame is realized, the test method is simple, the test assembly and system are simple, and the cost is low.

Description

Technical Field

[0001] The present invention belongs to the technical field of rolling shutter delay testing for CMOS image sensors, and particularly relates to a rolling shutter delay testing component, method, device and system for a CMOS image sensor. Background Art

[0002] A CMOS image sensor is a device that records optical signals through photoelectric conversion for imaging. During imaging, the pixels of the CMOS image sensor first collect incident photons and convert them into charges, a process called exposure. These charges are then read and converted into digital signals, which are recorded as a frame of image. During the imaging process of a frame of image, all pixels do not necessarily start exposure simultaneously. According to different shutter methods, the exposure logic is also different.

[0003] Due to the advantages of low noise and low cost, the rolling shutter is the most common and mature shutter method in the current field of CMOS image sensors. It also has the advantage of relatively low transmission bandwidth requirements and has advantages in terms of frame rate and frame speed. However, the rolling shutter also has limitations, that is, the exposure start times of the pixels in a single frame of image are not synchronized, which can cause image distortion. The rolling shutter achieves exposure by means of progressive scanning, that is, the image sensor scans row by row and exposes row by row until all pixel points are exposed. In this progressive exposure method, the exposure start times of the pixels are not synchronized, resulting in pixels in different rows being read at different times. That is, the positions of the object on the pixels in different rows may change at different times, ultimately resulting in distortion phenomena such as image tilt, wobbling, or partial exposure.

[0004] However, there is currently a lack of a testing method and device for the non-synchronization of pixel exposure within a single frame of a CMOS image sensor. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a rolling shutter delay testing component, method, device and system for a CMOS image sensor, so as to realize the testing of the non-synchronization of pixel exposure within a single frame of a CMOS image sensor.

[0006] The object of the present invention is achieved through the following technical solutions:

[0007] The first aspect of the present invention provides a rolling shutter delay testing component for a CMOS image sensor, including:

[0008] A test cylinder, on the outer sidewall of which are provided a plurality of test strips arranged along its axial direction. Among them, the distance between adjacent two test strips is equal, and the color of the test strip area is different from the area between adjacent two test strips;

[0009] A driving structure for driving the test cylinder to rotate uniformly around its rotation axis.

[0010] A second aspect of the present invention provides a method for testing the rolling shutter delay of a CMOS image sensor, characterized by including the following steps:

[0011] Obtain an image of the test cylinder in a CMOS image sensor rolling shutter delay test component described in any possible design of the first aspect when the shutter mode of the CMOS image sensor to be tested is a rolling shutter. Among them, when the CMOS image sensor to be tested captures the test cylinder, its test strip is parallel or perpendicular to the width direction of the CMOS image sensor;

[0012] Calculate the linear velocity of the test strip based on the diameter of the test cylinder and the output rotation speed of the driving structure;

[0013] Calculate the first pixel interval number between the two ends of a test strip in the image in the direction perpendicular to the rotation axis of the test cylinder and the second pixel interval number between the two ends of a test strip in the image in the axial direction;

[0014] Calculate the displacement distance based on the optical magnification, pixel size of the CMOS image sensor to be tested, and the first pixel interval number;

[0015] Calculate the exposure time difference between two adjacent test strips based on the displacement distance and the linear velocity of the test strip;

[0016] Obtain the exposure cycle time difference between two adjacent test strips based on the second pixel interval number and the exposure time difference between two adjacent test strips.

[0017] A third aspect of the present invention provides a device for testing the rolling shutter delay of a CMOS image sensor, including a memory and a controller that are communicatively connected in sequence. A computer program is stored on the memory, and the controller is used to read the computer program and execute a method for testing the rolling shutter delay of a CMOS image sensor described in the second aspect and any possible one thereof.

[0018] A fourth aspect of the present invention provides a system for testing the rolling shutter delay of a CMOS image sensor, including:

[0019] A CMOS image sensor rolling shutter delay test component described in the first aspect and any possible one thereof;

[0020] A device for testing the rolling shutter delay of a CMOS image sensor described in the third aspect and any possible one thereof.

[0021] Compared with the prior art, the present invention has at least the following advantages and beneficial effects:

[0022] The present invention realizes the test of the asynchronism of pixel exposure within a single frame according to the image of a test strip obtained by a CMOS image sensor. The test method is simple, the test components and system are simple, and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is a schematic structural diagram of the test strip of the present invention;

[0025] Figure 2 It is an image of a test cylinder taken by a CMOS image sensor to be tested. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the following will combine the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Usually, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0028] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0029] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0030] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, or the orientation or positional relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0031] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0032] The first aspect of the present invention provides a CMOS image sensor rolling shutter delay test component, which includes a test cylinder and a driving structure. Among them, a plurality of test strips are arranged axially on the outer side wall of the test cylinder, and the distance between adjacent two test strips is equal. The color of the test strip area is different from the area between adjacent two test strips. The driving structure is used to drive the test cylinder to rotate uniformly around its rotation axis.

[0033] In order to improve the applicable range of the CMOS image sensor tested by the component, preferably, the colors of the test strips and the area between adjacent two test strips are set to have a large contrast difference. For example, the color of the test strips is set to black, and the color of the area between adjacent two test strips is set to white; or the color of the test strips is set to white, and the color of the area between adjacent two test strips is set to black.

[0034] Exemplarily, the color of the test strips can be black, red, green, etc., and the color of the area between adjacent two test strips can be white, orange, etc. Due to the performance differences in the dynamic range of cameras, in the imaging results of some cameras with too small a dynamic range, the gray values of the stripes with a small contrast may have no difference, and even the saddle peak ratio is inherently zero when stationary. In this regard, preferably, the reflectivities of the test strip area and the area between adjacent two test strips are set to be different.

[0035] To improve the accuracy of the test and avoid the pattern in the imaging result being blurred or even merged into one piece and unable to be measured due to the influence of the camera MTF and integration time on the CMOS image sensor during shooting, resulting in low test accuracy. Preferably, the distance between two adjacent test strips is such that the saddle peak ratio of the imaging pattern is greater than 72%.

[0036] To improve the stability of the test cylinder and the driving structure, fix and absorb the rotational force during the rotation of the test cylinder, so that no non-circular motion displacement occurs in other components during the processes of acceleration, deceleration, and uniform motion. For this, the assembly further includes a bracket, and an installation groove for installing the test cylinder is provided on the bracket. Both ends of the test cylinder are rotatably connected in the installation groove and one end is connected to the driving structure. The bracket requires relatively high rigidity.

[0037] Specifically, the driving structure can be realized by using existing driving structures such as a stepper motor.

[0038] The main function of the test cylinder is to amplify the linear velocity, and there are also many ways to achieve it. For example, it can be directly solid with polystyrene. The test strip can be integrated with the test cylinder or can be formed by bonding a ring-shaped tape with strip-shaped test strips as shown in Figure 1 to the test cylinder.

[0039] The second aspect of the present invention provides a method for testing the rolling shutter delay of a CMOS image sensor. This method can be but is not limited to being executed by a device for testing the rolling shutter delay of a CMOS image sensor or being realized by manual operation. The device for testing the rolling shutter delay of a CMOS image sensor can be software or a combination of software and hardware, and the device for testing the rolling shutter delay of a CMOS image sensor can be integrated in intelligent devices such as intelligent mobile terminals, tablets, and computers. Specifically, the method for testing the rolling shutter delay of a CMOS image sensor includes the following steps S01 to step S06. It should be noted that the step identifiers in this solution are only for facilitating the description of the method and do not constitute a limitation on the sequence. The sequence of each step is subject to its language description and the sequential connection of each signal.

[0040] Step S01: Obtain an image of the test cylinder in one of the CMOS image sensor rolling shutter delay test components described in the first aspect and any possible design thereof when the shutter mode of the CMOS image sensor to be tested is the rolling shutter. Among them, when the CMOS image sensor to be tested shoots the test cylinder, the test strip is parallel or perpendicular to the width direction of the CMOS image sensor.

[0041] Among them, when the CMOS image sensor captures an image of the test cylinder, the test cylinder can be placed with its axis in a vertical state, a horizontal state, or other states, as long as the test strip of the test cylinder is parallel or perpendicular to the width direction of the CMOS image sensor during shooting.

[0042] Step S02: Calculate the linear velocity of the test strip based on the diameter of the test cylinder and the output rotational speed of the driving structure.

[0043] In this step, the output rotational speed of the driving structure is converted into the linear velocity of the test strip.

[0044] Specifically, the linear velocity V of the test strip is:

[0045] V = AπR,

[0046] where A is the output rotational speed of the driving structure and R is the diameter of the test cylinder.

[0047] Step S03: Calculate the first pixel interval number between the two ends of a test strip in the image in the direction perpendicular to the axis of the test cylinder and the second pixel interval number between the two ends of a test strip in the image in the axial direction.

[0048] Step S04: Calculate the displacement distance based on the optical object-image magnification, pixel size of the CMOS image sensor to be tested, and the first pixel interval number.

[0049] The optical object-image magnification is a parameter of the lens, which can be measured based on the imaging result of the CMOS image sensor to be tested and the actual spatial size of the real object; the pixel size is a parameter of the CMOS chip.

[0050] The displacement distance L obj is:

[0051] L obj = P 1 * L pixel / F,

[0052] where P 1 is the first pixel interval number, L pixel is the pixel size, and F is the optical object-image magnification.

[0053] Step S05: Calculate the exposure time difference between two adjacent test strips based on the displacement distance and the linear velocity of the test strip.

[0054] Specifically, the exposure time difference t test between two adjacent test strips is:

[0055] t test = L obj / V.

[0056] Step S06. Obtain the exposure cycle time difference between two adjacent test strips according to the second pixel interval number and the exposure time difference between two adjacent test strips.

[0057] Specifically, the exposure cycle time difference t between two adjacent test strips is:

[0058] t = t test / P 2 .

[0059] For ease of understanding, by way of example:

[0060] In a specific embodiment, the output rotational speed A of the driving structure is 0.8 revolutions per second, and the diameter R of the test cylinder is 0.5 meters. Then the linear velocity V of the test strip is:

[0061]

[0062] The image of the test cylinder captured by the CMOS image sensor to be tested is as Figure 2 shown. In the figure, [X, Y] represents the abscissa and ordinate of the pixel point, and Index represents the gray value of the pixel point; [R, G, B] represents the values of the red, green, and blue color channels of the pixel point. Then at this time, its first pixel interval number P1 and second pixel interval number P 2 are respectively:

[0063] P 1 = 561 - 483 = 78,

[0064] P 2 = 1008 - 533 = 475.

[0065] The optical object magnification F = 0.016, and the pixel size L pixel = 9.76 μm,

[0066] Then the displacement distance L obj is:

[0067] L obj = P 1 * L pixel / F = 0.046 meters.

[0068] Then the exposure time difference t test between two adjacent test strips is:

[0069] t test = L obj / V = 0.0366 seconds,

[0070] The exposure cycle time difference t between two adjacent test strips is:

[0071] t = t test / P2 = 77.029 microseconds.

[0072] The time difference t between the exposure periods of two adjacent test strips based on the above method can be used to simulate and calculate the distortion degree when the sensor images a moving object, and can also be used for imaging distortion correction of the corresponding sensor.

[0073] Based on the above method, a third aspect of the present invention provides a CMOS image sensor rolling shutter delay test device, including a memory and a controller that are communicatively connected in sequence. A computer program is stored on the memory, and the controller is configured to read the computer program and execute a CMOS image sensor rolling shutter delay test method described in the second aspect and any one of its possible embodiments. Specifically, for example, the memory may include, but is not limited to, random access memory (RAM), read-only memory (ROM), flash memory, first input first output (FIFO), and / or first input last output (FILO), etc.; the controller may not be limited to using a microcontroller of the STM32F105 series. In addition, the computer device may also include, but is not limited to, a power supply unit, a display screen, and other necessary components.

[0074] A fourth aspect of the present invention provides a CMOS image sensor rolling shutter delay test system, which includes a CMOS image sensor rolling shutter delay test component described in the first aspect and any one of its possible embodiments and a CMOS image sensor rolling shutter delay test device described in the third aspect and any one of its possible embodiments.

[0075] The method for using this system in conjunction with the CMOS image sensor to be tested is described in detail in the second aspect, so it will not be elaborated here.

[0076] Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A CMOS image sensor rolling shutter delay test assembly, characterized in that: include: A test cylinder, wherein a plurality of test strips are arranged along the axial direction of the test cylinder on the outside of the side wall of the test cylinder, wherein the spacing between two adjacent test strips is equal, and the color of the test strip area and the area between the two adjacent test strips are different; a driving structure, wherein the driving structure is used to drive the test cylinder to rotate at a uniform speed around its rotation axis.

2. A CMOS image sensor rolling shutter delay test according to claim 1, characterized in that: The color of the test strip is black, and the color of the area between two adjacent test strips is white; or, The color of the test strip is white, and the color of the area between two adjacent test strips is black.

3. The rolling shutter delay test of a CMOS image sensor according to claim 1, characterized in that: The reflectivity of the test strip area and the area between two adjacent test strips are different.

4. The rolling shutter delay test of a CMOS image sensor according to claim 1, characterized in that: It also includes a bracket, on which a mounting groove for mounting a test cylinder is arranged, and both ends of the test cylinder are rotatably connected in the mounting groove and one end is connected to the driving structure.

5. A rolling shutter delay test method for a CMOS image sensor, characterized in that: The following steps are involved: Acquire an image of the test barrel in the rolling shutter delay test assembly for a CMOS image sensor according to any one of claims 1 to 4, which is photographed when the CMOS image sensor to be tested is in a rolling shutter mode, wherein the test strip of the CMOS image sensor to be tested is parallel or perpendicular to the width direction of the CMOS image sensor when the test barrel is photographed; The linear velocity of the test strip is calculated according to the diameter of the test barrel and the output rotation speed of the driving structure; the first pixel interval number at both ends of a test strip in the image in a direction perpendicular to the rotation axis of the test barrel and the second pixel interval number at both ends of a test strip in the image in the axial direction are calculated; The displacement distance is calculated according to the optical image magnification, the pixel size and the first pixel interval number of the CMOS image sensor to be tested; Calculating the exposure time difference between two adjacent test strips according to the displacement distance and the linear speed of the test strip; The exposure period time difference between two adjacent test strips is obtained according to the second pixel interval number and the exposure time difference between two adjacent test strips.

6. A CMOS image sensor rolling shutter delay test method according to claim 1, characterized in that: The displacement distance calculated according to the optical image magnification, pixel size and the first pixel spacing number of the CMOS image sensor to be tested is: L obj =P1*L pixel / F, Among them, L obj is the displacement distance, P1 is the first pixel interval number, L pixel is the pixel size, and F is the optical image magnification.

7. A rolling shutter delay test method for a CMOS image sensor according to claim 6, characterized in that: The exposure time difference between two adjacent test strips calculated according to the displacement distance and the linear velocity of the test strip is: t test =L obj / V, Among them, t test is the exposure time difference between two adjacent test strips, and V is the linear speed of the test strips.

8. A rolling shutter delay test method for a CMOS image sensor according to claim 7, characterized in that: The exposure period time difference between two adjacent test strips obtained according to the second pixel interval number and the exposure time difference between two adjacent test strips is: t=t test / P2, Wherein, t is the exposure cycle time difference between two adjacent test strips, and P2 is the second pixel interval number.

9. A rolling shutter delay test device for a CMOS image sensor, comprising a memory and a controller which are communicatively connected in sequence, wherein a computer program is stored in the memory, and wherein: The controller is used to read the computer program and execute the rolling shutter delay testing method for a CMOS image sensor according to any one of claims 5 to 8.

10. A CMOS image sensor rolling shutter delay test system, characterized in that: include: A CMOS image sensor rolling shutter delay test assembly as claimed in any one of claims 1 to 4; A CMOS image sensor rolling shutter delay test device as claimed in claim 9.

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