A method and apparatus for testing image trailing in an image detection unit for a star sensor.

Abstract

A method and apparatus for testing image trailing in an image detection unit of a star sensor. The chip under test is mounted on the image trailing test board. A light-shielding tube is mounted on the front end of the image trailing test board using fixing screws. An LED light source is mounted on the end of the light-shielding tube. A light source driver box controls the LED light source via cables. The LED light source driver box is synchronously controlled by the image trailing test board, and its synchronization signal can control the LED light source to perform precise exposure control, precisely exposing a specified line of the image detection unit under test. The image trailing test board, light-shielding tube, and LED light source are mounted on a mounting bracket via the image trailing test board. A chip function testing computer controls the image trailing test board via cables and collects test data from the image trailing test board. A power supply box supplies power to the image trailing test board via power cables.

Description

Technical Field

[0001] This invention relates to a method and apparatus for testing image trailing in an image detection unit for star sensors, applicable to star sensors and other image detection sensors. Background Technology

[0002] Star sensors, as attitude sensors on existing satellite platforms, are used in multiple platforms and satellite models. Different platforms have different dynamic requirements for star sensors; some models require star sensors with high dynamic performance, thus placing high demands on their dynamic capabilities. The conventional approach is to conduct dynamic star sensor evaluation during the overall satellite observation phase to determine if it meets the application requirements. However, this conventional method has the drawback of being late in the evaluation process, leading to significant rework costs if unmet dynamic performance requirements are discovered. Summary of the Invention

[0003] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a method and apparatus for testing image trailing in the image detection unit of a star sensor, which solves the problem that the prior art cannot perform image trailing testing in the testing stage of the image detection unit.

[0004] The technical solution of the present invention is: an image trailing test device for an image detection unit of a star sensor, comprising a light source driving box, an image trailing test board, a light shielding tube, an LED light source, a mounting bracket, a chip function testing computer, and a power supply box;

[0005] The chip under test is mounted on the image trailing test board. The front end of the light-shielding tube is mounted on the image trailing test board with fixing screws. The LED light source is mounted on the end of the light-shielding tube. The light source driver box controls the LED light source through cables. The LED light source driver box is synchronously controlled by the image trailing test board. Its synchronization signal can control the LED light source to perform precise exposure control, and perform precise exposure for a specified line of the image detection unit under test. The image trailing test board, the light-shielding tube, and the LED light source are mounted on the mounting bracket through the image trailing test board. The chip function testing computer controls the image trailing test board through cables and collects the test data of the image trailing test board. The power supply box supplies power to the image trailing test board through power supply cables.

[0006] A method for testing image trailing in an image detection unit of a star sensor, comprising:

[0007] 1) The computer for chip function testing uses the default settings saved by the system to turn on the LED light source;

[0008] 2) Chip function testing: The computer-controlled image trailing test board performs image acquisition and calculates the average grayscale value of the acquired images.

[0009] 3) The chip function test computer controls the image trailing test board to increase the LED light source level by one level and continue the exposure. The chip function test computer performs grayscale average statistics on the exposed image.

[0010] 4) Repeat step 3) and gradually increase the LED level. Record the average gray value of the image corresponding to each level. Perform linear fitting on the recorded average gray value to find the LED level corresponding to its maximum linear value and record the level information.

[0011] 5) The LED light source is turned on according to the setting recorded in step 4), and the turning time is controlled by the external synchronization signal.

[0012] 6) The LED activation synchronization signal is controlled by the image trailing test board. The synchronization signal can control the LED light source to perform exposure control and expose the specified line of the detection unit of the image under test.

[0013] 7) Chip function test: Computer-controlled image trailing test board continuously exposes 4*N+1 frames; performs image grayscale value statistics for each frame.

[0014] 8) After exposure, the chip function test computer controls the image trailing test board to analyze the acquired image and obtain the image trailing result.

[0015] The timing control of the LED activation external synchronization signal is as follows: The image trailing test system sets control parameters M and N for two LED light sources. Line M+1 is set to the LED synchronization rise edge time, meaning the LED light source is activated at line M+1. Line N is set to the LED synchronization fall edge time, meaning the LED light source is deactivated at line N. Here, N is the set exposure line, and MN is the actual LED light exposure line. The first M lines are valid data, and data after M lines is invalid data.

[0016] The chip function detection computer-controlled image trailing test board analyzes the acquired images to obtain the image trailing result, including: treating the first 2*N frames as dark field images, and using the average grayscale value of the (N+1)th to 2*Nth images as the dark field grayscale value, denoted as DN. dark The (2*N+1)th frame image is the exposure image with the LED light source turned on, denoted as DN. bright The image trailing effect of the (2*N+2)th frame is calculated; the image trailing effect of subsequent frames is calculated in the same way, and finally the image trailing effect of all frames is obtained.

[0017] DN dark The calculation formula is:

[0018] Where DN (N+1) This is the grayscale value of the (N+1)th frame.

[0019] Image trailing at frame (2*N+2) 2*N+2 for DN 2*N+2 This represents the grayscale value of the image in the (2*N+2)th frame.

[0020] The advantages of this invention compared to the prior art are:

[0021] 1) The LED external synchronization signal is precisely synchronized by the image trailing test board. Its synchronization signal can control the LED light source to perform precise exposure control, and perform precise exposure for the specified line of the detection unit of the image under test. The host computer controls the position of the synchronous pulse exposure line, which can cover the full-image image trailing test.

[0022] 2) The synchronous light source adopts an LED combined with a light shield tube design. At the same time, the light shield tube is aligned with the chip image surface through mechanical design positioning. The light shield tube is blackened to eliminate the influence of multiple reflections in the light path inside the light shield tube. The system is compact and can be placed in a vacuum chamber for testing the relationship between image trailing of the image detection unit and temperature.

[0023] 3) Equipped with LED synchronization and driving power supply to ensure that the LED light source is controlled by the FPGA synchronization signal;

[0024] 4) LED light source brightness setting control levels, the control levels are continuously adjustable;

[0025] 5) The LED light source and the test chip are mechanically positioned to ensure that the LED light source illuminates the system under test evenly; Attached Figure Description

[0026] Figure 1 The diagram shown is a flowchart of the image trailing test of the present invention.

[0027] Figure 2 The diagram shown is a schematic diagram of the LED frame control for image trailing test according to the present invention;

[0028] Figure 3 The diagram shown is a timing diagram of the LED row control for image trailing test according to the present invention;

[0029] Figure 4 The image shown is a schematic diagram of the image trailing test results of the present invention;

[0030] Figure 5 The diagram shows the image trailing test device of the present invention. Detailed Implementation

[0031] This invention proposes a method and apparatus for testing image trailing in an image detection unit for a star sensor. The apparatus includes a light source driver box, an image trailing test board, a light shield, an LED light source, a mounting bracket, a chip function testing computer, and a power supply box.

[0032] The chip under test is mounted on the image trailing test board. The front end of the light-shielding tube is mounted on the image trailing test board with fixing screws. The LED light source is mounted on the end of the light-shielding tube. The light source driver box controls the LED light source through cables. The LED light source driver box is synchronously controlled by the image trailing test board. Its synchronization signal can control the LED light source to perform precise exposure control, and perform precise exposure for a specified line of the image detection unit under test. The image trailing test board, the light-shielding tube, and the LED light source are mounted on the mounting bracket through the image trailing test board. The chip function testing computer controls the image trailing test board through cables and collects the test data of the image trailing test board. The power supply box supplies power to the image trailing test board through power supply cables.

[0033] An image trailing test procedure for an image detection unit suitable for star sensors is as follows: Figure 1 As shown.

[0034] Figure 1 The image trailing test procedure is described as follows:

[0035] 1) The computer for chip function testing uses the default settings saved by the system to turn on the LED light source;

[0036] 2) The chip function testing computer controls the image trailing test board to acquire images, and the chip function testing computer calculates the grayscale mean of the acquired images.

[0037] 3) The chip function test computer controls the image trailing test board to increase the LED light source level by one level and continue the exposure. The chip function test computer performs grayscale average statistics on the exposed image.

[0038] 4) Based on the gradual increase of LED levels in step 3), record the average gray value of the image corresponding to each level. When the average gray value of the image corresponding to each level is reached, perform linear fitting on the recorded average gray value to find the LED level corresponding to its maximum linear value, and record the level information.

[0039] 5) The LED light source is turned on according to the recording position in step 4), and the turning time is controlled by the external synchronization signal;

[0040] 6) The LED activation external synchronization signal is precisely synchronized by the image trailing test board. Its synchronization signal can control the LED light source to perform precise exposure control and perform precise exposure for the specified line of the detection unit of the image under test.

[0041] 7) Chip function testing computer-controlled image trailing test board continuously exposes 4*N+1 frames;

[0042] 8) After exposure, the chip function test computer controls the image trailing test board to analyze the acquired image. In step 5), the first 2*N frames are dark field images, and the average gray level of the (N+1)th to 2*Nth images is used as the dark field gray level value, denoted as DN. dark The calculation formula is: In the above formula, DN (N+1) DN is the grayscale value of the (N+1)th frame; the image of the (2*N+1)th frame is the exposure image with the LED light source on, denoted as DN. bright The image trailing at frame (2*N+2) is calculated as follows: The calculation of image trailing in subsequent frames follows the same principle.

[0043] In the above process, parallel light LEDs are used as the LED light source, and the synchronization signal needs to be derived from the image trailing test board. The relationship between the frame synchronization signal and the pixel control signal is as follows: Figure 2 As shown, the LED light source is turned on and off by line counting control in the 21st frame. The relationship between the line synchronization signal and the pixel control signal is shown in the figure. Figure 3 As shown.

[0044] like Figure 3 As shown, the image trailing test system has two parameters: M+1 row is the LED synchronization rise time (i.e., the LED light source starts at row M+1), and N row is the LED synchronization fall time (i.e., the LED light source stops at row N). N represents the set exposure rows, and MN represents the actual LED light exposure rows. The first M rows are valid data, and data after M rows is invalid. M and N are configurable by the host computer.

[0045] After image acquisition is completed, the acquired images undergo data processing, such as... Figure 2 The test timing shown involves dark-field exposure in the first N frames to allow the image detection unit to reach dynamic equilibrium in the dark field. Simultaneously, the average value of the dark-field images from frame (N+1) to frame 2*N is used as the background mean, denoted as DN. dark The calculation formula is as follows:

[0046]

[0047] In the above formula, DN (N+1) DN is the grayscale value of the (N+1)th frame; the image of the (2*N+1)th frame is the exposure image with the LED light source on, denoted as DN. bright The image trailing at frame (2*N+2) is calculated as follows:

[0048]

[0049] The trailing effect calculation for subsequent frames is performed in the same manner. For example... Figure 4 As shown.

[0050] The block diagram of the image trailing test system is as follows: Figure 5 As shown, the image trailing test system mainly consists of an image trailing test board, mounting bracket, LED light source, LED light source driver circuit, and corresponding cables and connectors. The power supply and chip function testing computer in the figure are used to assist the image trailing test system in power supply and image acquisition.

[0051] The parts of this patent that are not described in detail are common knowledge to those skilled in the art.

Claims

1. An image trailing test device for an image detection unit of a star sensor, characterized in that: Includes light source driver box, image trailing test board, light shield, LED light source, mounting bracket, chip function testing computer, and power supply box; The chip under test is mounted on the image trailing test board. The front end of the light-shielding tube is mounted on the image trailing test board with fixing screws. The LED light source is mounted on the end of the light-shielding tube. The light source driver box controls the LED light source through cables. The LED light source driver box is synchronously controlled by the image trailing test board. Its synchronization signal can control the LED light source to perform precise exposure control, and perform precise exposure for a specified line of the image detection unit under test. The image trailing test board, the light-shielding tube, and the LED light source are mounted on the mounting bracket through the image trailing test board. The chip function testing computer controls the image trailing test board through cables and collects the test data of the image trailing test board. The power supply box supplies power to the image trailing test board through power supply cables.

2. A method for testing image trailing in an image detection unit for a star sensor, characterized in that... include: 1) The computer for chip function testing uses the default settings saved by the system to turn on the LED light source; 2) Chip function testing: The computer-controlled image trailing test board performs image acquisition and calculates the average grayscale value of the acquired images. 3) The chip function test computer controls the image trailing test board to increase the LED light source level by one level and continue the exposure. The chip function test computer performs grayscale average statistics on the exposed image. 4) Repeat step 3) and gradually increase the LED level. Record the average gray value of the image corresponding to each level. Perform linear fitting on the recorded average gray value to find the LED level corresponding to its maximum linear value and record the level information. 5) The LED light source is turned on according to the setting recorded in step 4), and the turning time is controlled by the external synchronization signal. 6) The LED activation synchronization signal is controlled by the image trailing test board. The synchronization signal can control the LED light source to perform exposure control and expose the specified line of the detection unit of the image under test. 7) Chip function testing computer-controlled image trailing test board continuously exposes 4*N+1 frames; Perform image grayscale value statistics for each frame; 8) After exposure, the chip function test computer controls the image trailing test board to analyze the acquired image and obtain the image trailing result.

3. The image trailing test method for an image detection unit of a star sensor according to claim 2, characterized in that: The chip function detection computer-controlled image trailing test board analyzes the acquired images to obtain the image trailing result, including: treating the first 2*N frames as dark field images, and using the average grayscale value of the (N+1)th to 2*Nth images as the dark field grayscale value, denoted as DN. dark The (2*N+1)th frame image is the exposure image with the LED light source turned on, denoted as DN. bright The image trailing effect of the (2*N+2)th frame is calculated; the image trailing effect of subsequent frames is calculated in the same way, and finally the image trailing effect of all frames is obtained.

4. The image trailing test method for an image detection unit for a star sensor according to claim 3, characterized in that: Image trailing at frame (2*N+2) 2*N+2 for DN 2*N+2 This represents the grayscale value of the image in the (2*N+2)th frame.

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