TDI remote sensing camera push-scan direction testing device and method

Abstract

The invention discloses a TDI remote sensing camera push-broom direction testing device and method, and solves the technical problems that the economic cost of an existing testing method is very high, and the mechanical structure precision of a two-dimensional turntable is difficult to reach a sub-pixel angular resolution level. The TDI remote sensing camera push-scan direction testing device comprises a collimator, a position and posture adjusting platform, an LED lamp array target, an LED lamp array target driving control device and a time synchronization device. The collimator is provided with an entrance port and an exit port, and the TDI remote sensing camera is installed at the exit port; the position and posture adjusting platform is mounted at the entrance port and comprises a two-dimensional translation table, an electric rotating table and a control device; the LED lamp array target is an LED lamp array with L rows and N columns, N is larger than L, and the LED lamp array target is installed on the electric rotating table and electrically connected with the LED lamp array target driving control device; and the time synchronization device is electrically connected with the LED lamp array target driving control device and the TDI remote sensing camera.

Description

Technical Field

[0001] This invention relates to a testing device and method for TDI remote sensing cameras, specifically to a testing device and method for the push-broom direction of a TDI remote sensing camera. Background Technology

[0002] TDI-CCD (Time Delay and Integration Charge-Coupled Device) has broad application prospects in the field of aerospace remote sensing. TDI-CCD can achieve high sensitivity without sacrificing spatial resolution and operating speed, while also increasing the system's signal-to-noise ratio, resolution, and response uniformity. It is a major technical approach and key technical measure for achieving lightweight remote sensing.

[0003] TDI-CCD remote sensing cameras are aerospace / aviational remote sensing imaging devices equipped with time-delay integrated charge-coupled devices (TCDs). They rely on the superposition of multiple TDI charge levels to enhance light sensitivity, enabling clear imaging of high-speed moving platforms. The development of TDI-CCD remote sensing cameras is a complex engineering project requiring comprehensive testing. Pushbroom orientation testing is an essential component of this process. An incorrect pushbroom orientation is a very specific and serious engineering problem that will cause a mismatch between the data acquisition timing or data stream sequence within the TDI-CCD remote sensing camera and the physical motion direction of the TDI-CCD, resulting in completely incorrect geometric relationships in the captured images.

[0004] In existing technologies, pushbroom orientation testing of TDI-CCD remote sensing cameras typically requires using a two-dimensional turntable to simulate the mounting platform of the TDI-CCD remote sensing camera, and using a collimator with a larger aperture and longer focal length than the TDI-CCD remote sensing camera under test to simulate an infinity target. The correctness of the TDI-CCD remote sensing camera's pushbroom orientation is determined by the matching of the rotation direction of the two-dimensional turntable with the expected timing of the collimator target image acquired by the TDI-CCD remote sensing camera. However, this testing method has the following drawbacks: First, large TDI-CCD remote sensing cameras are heavy and have large apertures, making it difficult to find a matching two-dimensional turntable and collimator, resulting in very high testing costs; second, large TDI-CCD remote sensing cameras have high angular resolution, requiring the positioning accuracy of the two-dimensional turntable to reach the sub-pixel angular resolution level, while the mechanical structure accuracy of existing two-dimensional turntables is generally insufficient to meet this positioning accuracy requirement. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problems that the economic cost of existing testing methods is very high and the mechanical structure accuracy of two-dimensional turntables is difficult to reach the sub-pixel angular resolution level, and to provide a push-broom direction testing device and method for TDI remote sensing cameras.

[0006] To achieve the above-mentioned objectives, the technical solution provided by this invention is as follows:

[0007] A push-broom orientation testing device for a TDI remote sensing camera is characterized by including a collimator, a position and attitude adjustment platform, an LED light array target, an LED light array target drive control device, and a time synchronization device.

[0008] The collimator has an inlet and an outlet, and a TDI remote sensing camera mounting position is provided outside its outlet for mounting the TDI remote sensing camera to be tested.

[0009] The position and attitude adjustment platform is set at the entrance of the collimator and includes a two-dimensional translation stage, an electric rotary stage and a control device. The electric rotary stage is installed on the load mounting surface of the two-dimensional translation stage. The control device is electrically connected to the two-dimensional translation stage and the electric rotary stage respectively, and is used to control the horizontal movement of the two-dimensional translation stage and the rotation of the electric rotary stage.

[0010] The LED light array target is an LED light array with L rows and N columns, which is mounted on an electric rotating platform and electrically connected to the LED light array target drive control device. ;

[0011] The time synchronization device is electrically connected to the LED light array target drive control device and the TDI remote sensing camera, respectively, and is used to synchronize the output time of the drive signal output by the LED light array target drive control device with the start imaging time of the TDI remote sensing camera. The drive signal includes all LED lights constantly on signal, single row of LED lights on signal, LED lights on signal, and LED light brightness adjustment signal to control the operation of the LED light array target.

[0012] Furthermore, defining A as the ratio adjustment coefficient between the number of columns and the number of rows, we have: , , where n is the number of pixel columns in the TDI remote sensing camera.

[0013] Furthermore, the LED light array target is arranged radially on the electric rotating platform, with its two ends equidistant from the center of rotation of the electric rotating platform.

[0014] Meanwhile, the present invention also provides a method for testing the push-broom orientation of a TDI remote sensing camera, which is characterized by including the following steps:

[0015] Step 1: Construct the TDI remote sensing camera push-broom orientation test device described above;

[0016] Step 2: Install the TDI remote sensing camera into the TDI remote sensing camera mounting position and determine its line frequency, frame frequency, line period, and exposure time;

[0017] Step 3: Control the movement of the two-dimensional translation stage through the control device to move the LED light array target to the focal plane of the collimator;

[0018] Step 4: Send a signal to the LED light array target drive control device to keep all LED lights on so that all LED lights on the LED light array target are kept on so that bright bars appear in the image captured by the TDI remote sensing camera. The bright bars are made as wide as possible by controlling the rotation of the electric rotary table.

[0019] Step 5: Send a single-row LED light lighting signal to the LED light array target drive control device through the time synchronization device. The LED light array target drive control device controls the first row of LED lights or the Nth row of LED lights of the LED light array target to light up, determine the position of the bright bar in the image captured by the TDI remote sensing camera, and obtain the lighting sequence and direction of the LED lights of the LED light array target in the image captured by the TDI remote sensing camera.

[0020] Step 6: Synchronize the start imaging time of the TDI remote sensing camera with the output time of the drive signal from the LED light array target drive control device using the time synchronization device.

[0021] Step 7: Based on the row frequency, frame frequency, row period, and exposure time of the TDI remote sensing camera, determine the column switching frequency of the N columns of LEDs and the preset lighting time of a single column of LEDs. Send the LED lighting signal to the LED array target drive control device through the time synchronization device. The LED array target drive control device controls the N columns of LEDs of the LED array target to be lit in a cyclical manner according to the column switching frequency from 1 to N, or from N to 1, with only one column of LEDs lit at a time. After the preset lighting time, the LEDs are turned off.

[0022] Step 8: The time synchronization device sends an LED brightness adjustment signal to the LED light array target drive control device, and the LED light array target drive control device adjusts the brightness of all LED lights on the LED light array target so that the image captured by the TDI remote sensing camera shows a diagonal trend.

[0023] Step 9: Based on the LED lighting sequence and direction of the LED light array target (2) in the TDI remote sensing camera image obtained in Step 5, and the direction of the diagonal trend in the TDI remote sensing camera image obtained in Step 8, obtain the push-broom direction of the TDI remote sensing camera and complete the push-broom direction test of the TDI remote sensing camera.

[0024] Furthermore, in step 5, the specific process of obtaining the LED lighting sequence and direction of the LED light array target in the TDI remote sensing camera image is as follows:

[0025] If the first row of LEDs on the LED array target is lit, or the Nth row of LEDs is lit, and the position of the bright bar is on the far left of the image captured by the TDI remote sensing camera, then the lighting order of the LEDs on the LED array target in the image captured by the TDI remote sensing camera is from left to right.

[0026] If the first row of LEDs on the LED array target is lit, or the Nth row of LEDs is lit, and the position of the bright bar is on the far right of the image captured by the TDI remote sensing camera, then the lighting sequence of the LEDs on the LED array target in the image captured by the TDI remote sensing camera is from right to left.

[0027] Furthermore, in step 7, the column switching frequency is consistent with the row frequency of the TDI remote sensing camera, and the total time required for all the LEDs of the LED light array target to light up once is less than or equal to the frame rate of the TDI remote sensing camera.

[0028] The preset time is less than the line period of the TDI remote sensing camera and greater than the exposure time of the TDI remote sensing camera.

[0029] Compared with the prior art, the present invention has the following beneficial technical effects:

[0030] 1. The present invention provides a push-broom direction testing device for TDI remote sensing cameras. Through a collimator and an LED light array target, it realizes flexible and variable target scene simulation. It is suitable for push-broom direction testing of various TDI remote sensing cameras. The device uses a position and attitude adjustment platform to test the position and attitude of the moving LED light array target. The TDI remote sensing camera does not need to move during the test, which improves the safety of the test process. In addition, the overall structure is simple and easy to manufacture or assemble.

[0031] 2. This invention provides a push-broom direction testing method for TDI remote sensing cameras. The method is simple to operate, the test results are easy to interpret, and it is easy to implement in engineering, greatly reducing the testing time. Furthermore, it simplifies the target-TDI remote sensing camera matching process. The matching design is completed based on the TDI remote sensing camera's line frequency, frame frequency, line period, and exposure time, eliminating the need to calculate the TDI remote sensing camera's velocity-to-height ratio or to perform precise push-broom speed matching through a sophisticated motion mechanism, significantly simplifying test preparation. Simultaneously, it has lower requirements for the clarity of the LED light array target image, eliminating the need for fine-tuning the TDI remote sensing camera's imaging parameters. Test results can be obtained simply by interpreting the target's diagonal trend, significantly shortening the overall testing time. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of an embodiment of a push-broom direction testing device for a TDI remote sensing camera according to the present invention.

[0033] Figure 2This is a schematic diagram of the structure of an LED light array target in an embodiment of a TDI remote sensing camera push-broom direction testing device of the present invention;

[0034] Figure 3 This is a schematic diagram of the first push-broom direction of an image captured by a TDI remote sensing camera, obtained from an embodiment of a push-broom direction testing method for a TDI remote sensing camera according to the present invention.

[0035] Figure 4 This is a schematic diagram of the second push-broom direction of an image captured by a TDI remote sensing camera, obtained from an embodiment of a push-broom direction testing method for a TDI remote sensing camera according to the present invention.

[0036] Figure 5 This is a schematic diagram of the third push-broom direction of an image captured by a TDI remote sensing camera, obtained from an embodiment of a push-broom direction testing method for a TDI remote sensing camera according to the present invention.

[0037] Figure 6 This is a schematic diagram of the fourth push-broom direction of an image captured by a TDI remote sensing camera, obtained from an embodiment of the push-broom direction testing method of a TDI remote sensing camera according to the present invention.

[0038] The annotations in the attached figures are explained as follows:

[0039] 1. Collimator; 2. LED light array target; 3. Position and attitude adjustment platform; 301. Control device; 5. LED light array target drive control device; 6. Time synchronization device; 7. TDI remote sensing camera. Detailed Implementation

[0040] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0041] like Figure 1-6 As shown, this embodiment provides a TDI remote sensing camera push-broom direction testing device for testing the push-broom direction of a TDI remote sensing camera. It includes a collimator 1, a position and attitude adjustment platform 3, an LED light array target 2, an LED light array target drive control device 5, and a time synchronization device 6.

[0042] The collimator 1 has an inlet and an outlet, and a TDI remote sensing camera mounting position is provided outside its outlet for mounting the TDI remote sensing camera 7 to be tested.

[0043] The position and attitude adjustment platform 3 is set at the entrance of the collimator 1. It includes a two-dimensional translation stage, an electric rotary stage and a control device 301. The electric rotary stage is installed on the load mounting surface of the two-dimensional translation stage. The control device 301 is electrically connected to the two-dimensional translation stage and the electric rotary stage respectively, and is used to control the horizontal movement of the two-dimensional translation stage and the rotation of the electric rotary stage.

[0044] LED light array target 2 is an LED light array with L rows and N columns. It is mounted on an electric rotating platform and electrically connected to the LED light array target drive control device 5. , n is the number of pixel columns in the TDI remote sensing camera 7;

[0045] The time synchronization device 6 is electrically connected to the LED light array target drive control device 5 and the TDI remote sensing camera 7 respectively. It is used to synchronize the signal output time of the LED light array target drive control device 5 with the start imaging time of the TDI remote sensing camera 7. At the same time, it sends all LED light constant light signals, single row LED light lighting signals, LED light lighting signals and LED light brightness adjustment signals to the LED light array target drive control device 5 to control the operation of the LED light array target 2.

[0046] Meanwhile, the present invention also provides a method for testing the push-broom orientation of a TDI remote sensing camera, comprising the following steps:

[0047] Step 1: Construct the TDI remote sensing camera push-broom orientation test device described above;

[0048] Step 2: Install the TDI remote sensing camera 7 into the TDI remote sensing camera mounting position, and determine its line frequency, frame frequency, line period, and exposure time;

[0049] Step 3: Control the movement of the two-dimensional translation stage through the control device 301 to move the LED light array target 2 to the focal plane of the collimator 1;

[0050] Step 4: Send all LED lights on signal to LED light array target drive control device 5 through time synchronization device 6 to control all LED lights on LED light array target 2 to be on, so that bright bars appear in the image captured by TDI remote sensing camera 7. Control the electric rotary table to rotate so that the bright bars reach their widest width.

[0051] Step 5: The time synchronization device 6 sends a single-row LED lighting signal to the LED array target drive control device 5. The LED array target drive control device 5 controls the first or Nth row of LEDs in the LED array target 2 to light up, determining the position of the bright bars in the image captured by the TDI remote sensing camera 7, and obtaining the lighting sequence direction of the LEDs in the LED array target 2 in the image captured by the TDI remote sensing camera 7. The specific process of determining the lighting sequence direction of the LEDs in the LED array target 2 in the image captured by the TDI remote sensing camera 7 is as follows:

[0052] In images captured by the TDI remote sensing camera 7, the bright bars are located at either the far left or far right of the image.

[0053] If the LED light array target 2 lights up the first column of LEDs, or lights up the Nth column of LEDs, and the position of the bright bar is on the far left of the image captured by the TDI remote sensing camera 7, then the lighting sequence of the LEDs of the LED light array target 2 in the image captured by the TDI remote sensing camera 7 is from left to right.

[0054] If the LED target 2 lights up the first column of LEDs, or the Nth column of LEDs, and the position of the bright bar is on the far right of the image captured by the TDI remote sensing camera 7, then the lighting sequence of the LEDs on the LED target 2 in the image captured by the TDI remote sensing camera 7 is from right to left.

[0055] Step 6: Synchronize the start imaging time of the TDI remote sensing camera 7 with the output time of the drive signal from the LED light array target drive control device 5 through the time synchronization device 6.

[0056] Step 7: Based on the row frequency, frame frequency, row period, and exposure time of the TDI remote sensing camera 7, determine the column switching frequency of the N columns of LEDs and the preset lighting time for a single column of LEDs. Send an LED lighting signal to the LED array target drive control device 5 through the time synchronization device 6. The LED array target drive control device 5 controls the N columns of LEDs of the LED array target 2 to be lit in a cyclical manner according to the column switching frequency from 1 to N, or from N to 1, with only one column of LEDs lit at a time. After the preset lighting time, the LEDs are turned off. The column switching frequency is consistent with the row frequency of the TDI remote sensing camera 7, and the total time required for all LEDs of the LED array target 2 to be lit once is less than or equal to the frame frequency of the TDI remote sensing camera 7. The preset time is less than the row period of the TDI remote sensing camera 7 and greater than the exposure time of the TDI remote sensing camera 7.

[0057] Step 8: The time synchronization device 6 sends an LED brightness adjustment signal to the LED light array target drive control device 5, and adjusts the brightness of all LEDs in the LED light array target 2 through the LED light array target drive control device 5 so that the image captured by the TDI remote sensing camera 7 shows a diagonal trend.

[0058] Step 9: Based on the LED lighting sequence and direction of the LED light array target 2 in the image captured by the TDI remote sensing camera 7 obtained in Step 5, and the direction of the diagonal trend in the image captured by the TDI remote sensing camera 7 in Step 8, obtain the push-broom direction of the TDI remote sensing camera, and complete the push-broom direction test of the TDI remote sensing camera.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A TDI remote sensing camera push scan direction testing apparatus, characterized by: The device comprises a collimator (1), a position and posture adjusting platform (3), an LED lamp array target (2), an LED lamp array target driving control device (5) and a time synchronization device (6). The collimator (1) has an entrance and an exit, and a TDI remote sensing camera mounting position is arranged outside the exit of the collimator (1) for mounting a TDI remote sensing camera (7) to be tested. The position and posture adjusting platform (3) is arranged at the entrance of the collimator (1) and comprises a two-dimensional translation table, a motorized rotary table and a control device (301), the motorized rotary table is mounted on the load mounting surface of the two-dimensional translation table, and the control device (301) is electrically connected with the two-dimensional translation table and the motorized rotary table respectively for controlling the horizontal movement of the two-dimensional translation table and the rotation of the motorized rotary table. The LED lamp array target (2) is an LED lamp array with L rows and N columns, which is installed on an electric rotating table and electrically connected with the LED lamp array target driving control device (5), wherein, N is greater than L. The time synchronization device (6) is electrically connected with the LED lamp array target driving control device (5) and the TDI remote sensing camera (7) respectively for synchronizing the output time of the driving signal output by the LED lamp array target driving control device (5) and the start imaging time of the TDI remote sensing camera (7), and the driving signal comprises all LED lamp constant-on signals, single-column LED lamp lighting signals, LED lamp lighting signals and LED lamp brightness adjusting signals for controlling the operation of the LED lamp array target (2).

2. The TDI remote-sensing camera push-scan direction testing apparatus of claim 1, wherein: Definition A is the proportionality adjustment factor between the number of columns and the number of rows, so that: , n is the number of pixel columns of the TDI remote sensing camera (7).

3. The TDI remote sensor camera push scan direction testing apparatus of claim 1, wherein: The LED lamp array target (2) is arranged radially on the motorized rotary table and the distance between the two ends of the LED lamp array target (2) and the rotation center of the motorized rotary table is equal.

4. A method of testing a push scan direction of a TDI remote sensing camera, the method comprising: The device comprises the following steps: Step 1, constructing the TDI remote sensing camera push-scan direction testing device according to any one of claims 1-3; Step 2, mounting the TDI remote sensing camera (7) to the TDI remote sensing camera mounting position and determining the line frequency, frame frequency, line period and exposure time of the TDI remote sensing camera (7); Step 3, moving the LED lamp array target (2) to the focal plane of the collimator (1) by controlling the two-dimensional translation table to move through the control device (301); Step 4, controlling all the LED lamps on the LED lamp array target (2) to be constantly on by sending all the LED lamp constant-on signals to the LED lamp array target driving control device (5) through the time synchronization device (6) so that a bright strip appears in the image captured by the TDI remote sensing camera (7), and the bright strip reaches the maximum width by controlling the motorized rotary table to rotate; Step 5, determining the position of the bright strip in the image captured by the TDI remote sensing camera (7) and obtaining the LED lamp lighting sequence direction of the LED lamp array target (2) in the image captured by the TDI remote sensing camera (7) by sending the single-column LED lamp lighting signal to the LED lamp array target driving control device (5) through the time synchronization device (6), and the LED lamp array target driving control device (5) controls the first column of LED lamps or the Nth column of LED lamps on the LED lamp array target (2) to light up; Step 6, synchronizing the start imaging time of the TDI remote sensing camera (7) and the output time of the driving signal output by the LED lamp array target driving control device (5). Step 7, according to the line frequency, frame frequency, line period and exposure time of the TDI remote sensing camera (7), determine the column switching frequency of the N column LED lamp and the preset time of the single column LED lamp, send the LED lamp lighting signal to the LED lamp array target driving control device (5) through the time synchronization device (6), the LED lamp array target driving control device (5) controls the N column LED lamp of the LED lamp array target (2) to light in the order of 1 to N or N to 1 according to the column switching frequency, and only one column of LED lights up each time, and turns off after the preset time; Step 8, the time synchronization device (6) sends the LED lamp brightness adjustment signal to the LED lamp array target driving control device (5), and adjusts the brightness of all LED lamps of the LED lamp array target (2) through the LED lamp array target driving control device (5), so that the image captured by the TDI remote sensing camera (7) shows a diagonal trend; Step 9, according to the LED lamp lighting sequence direction of the LED lamp array target (2) in the image captured by the TDI remote sensing camera (7) obtained in step 5, and the direction of the diagonal trend of the image captured by the TDI remote sensing camera (7) in step 8, obtain the push direction of the TDI remote sensing camera, and complete the test of the push direction of the TDI remote sensing camera.

5. The TDI remote sensing camera push scan direction testing method of claim 4, wherein, In step 5, the specific process of obtaining the LED lamp lighting sequence direction of the LED lamp array target (2) in the image captured by the TDI remote sensing camera (7) is as follows: If the first column of LED lamps or the Nth column of LED lamps of the LED lamp array target (2) are lit, and the position of the bright strip is on the leftmost side of the image captured by the TDI remote sensing camera (7), then the LED lamp lighting sequence direction of the LED lamp array target (2) in the image captured by the TDI remote sensing camera (7) is from left to right; If the first column of LED lamps or the Nth column of LED lamps of the LED lamp array target (2) are lit, and the position of the bright strip is on the rightmost side of the image captured by the TDI remote sensing camera (7), then the LED lamp lighting sequence direction of the LED lamp array target (2) in the image captured by the TDI remote sensing camera (7) is from right to left.

6. The TDI remote-sensing camera push-scan direction testing method of claim 4, wherein: In step 7, the column switching frequency is consistent with the line frequency of the TDI remote sensing camera (7), and the total time required for lighting all the LED lamps of the LED lamp array target (2) is less than or equal to the frame frequency of the TDI remote sensing camera (7); The preset time is less than the line period of the TDI remote sensing camera (7) and greater than the exposure time of the TDI remote sensing camera (7).

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