Rapid and high-precision detection method for transfer function of detector

Abstract

The invention belongs to the field of detector transfer function detection, and particularly relates to a rapid and high-precision detector transfer function detection method. The method comprises the following steps that S1, a detector is connected with a multi-dimensional adjusting mechanism; s2, any three-point target identification of the detector; s3, taking the target as a reference, and enabling the leveled height deviation to meet a set deviation condition; s4, performing parallel correction on the detector and the target; s5, the parallel deviation value meets a set deviation condition; s6, determining the clear focal plane position of the detector; a corresponding step length is set by taking the focal depth of the lens as a reference, and a scanning curve is established for the detector. According to the invention, the adjustment precision of the relative poses of the detector and the detection lens can be improved, and the problem of insufficient transfer function detection precision caused by improper installation is reduced; efficient calibration of the focal plane position of the detector can be realized, so that an actual detection value is closer to a true value result; and damage to the surface of the detector can be avoided.

Description

Technical Field

[0001] The present invention relates to a detector transmission function detection method, and in particular to a detector transmission function rapid and high-precision detection method. Background Art

[0002] The detector is the core component of a space optical camera. The value of its transfer function determines the quality of the final image. The currently used detector transfer function detection method has the following shortcomings:

[0003] 1. Usually, the detector position is adjusted using an image plane trimming pad to locate it at the focal plane of the optical lens to achieve transducer detection. This process requires multiple disassembly and assembly of the detector, which can easily cause damage to the detector and has low transducer detection efficiency.

[0004] 2. When using a trimming pad to adjust the detector position, the focus curve is usually established with a trimming pad adjustment accuracy of 0.01mm. It is impossible to improve the focus curve accuracy through more precise trimming adjustment, resulting in insufficient sampling of the detector's transfer function curve, affecting the test results;

[0005] 3. In the traditional detector transmission signal detection method, there is a deviation in the installation position between the detector and the optical lens, which can easily cause the actual value of the transmission signal detection to differ from the true value;

[0006] 4. When the detector consists of multiple channels, the traditional signal transmission detection method requires the use of a high-precision multi-dimensional adjustment mechanism for push scanning, which is cumbersome;

[0007] 5. For batch testing, traditional methods cannot be completed within the effective time. Summary of the Invention

[0008] The purpose of the present invention is to solve the technical problems that the existing detection methods are prone to cause damage to the detector, and the efficiency of the transfer function detection is low; the transfer function curve sampling is insufficient, affecting the detection results; it is easy to cause the actual value of the transfer function detection to differ from the true value; the workload is cumbersome; and it cannot be completed within the effective time. By providing a method for fast and high-precision detection of the detector transfer function.

[0009] To achieve the above object, the technical solution adopted by the present invention is:

[0010] A method for rapid and high-precision detection of a detector transmission function is characterized in that it includes the following steps:

[0011] S1. Connect the detector to the multi-dimensional adjustment mechanism, and then place the connected detector and multi-dimensional adjustment mechanism on the development three-coordinate optical platform;

[0012] S2. Level the detector using a multi-dimensional adjustment mechanism. Using any three points on the non-photosensitive surface of the detector as targets, measure the heights of the three targets using a developing three-dimensional coordinate measuring instrument. Determine whether the average of the maximum deviations of the heights of the three targets meets the set difference condition. If so, leveling is complete. If not, re-level the detector using the multi-dimensional adjustment mechanism, using the average of the maximum and minimum heights of the three points as the adjustment reference, until the set difference condition is met.

[0013] S3. Using a three-dimensional coordinate measuring machine, adjust the relative position between the detection lens mounted thereon and the photosensitive surface of the detector so that a striped target built into the detection lens is imaged by the detector, and the image clarity meets the set clarity requirements;

[0014] S4. Adjusting the relative spin position of the detector and the target by the multi-dimensional adjustment mechanism to determine whether the spin position deviation satisfies a set deviation condition. If so, the relative spin position adjustment of the detector and the target is completed; if not, the relative spin position of the detector and the target is readjusted by the multi-dimensional adjustment mechanism until the set deviation condition is satisfied.

[0015] S5. Use the developing three-dimensional coordinate measuring machine and the detection lens to determine the focal plane position of the detector;

[0016] S6. Use a developing three-dimensional coordinate measuring instrument to perform focus sampling on the clarity of the target image at the focal plane position of the detector to obtain the focus sampling image information. Based on the focus sampling image information, an overfocus curve is constructed and a focus curve algorithm is used for machine vision interpretation. The average value of the interpretation is obtained to realize the detector transmission function detection.

[0017] Furthermore, in S1, the detector includes a detector body and a socket assembly; the multi-dimensional adjustment mechanism includes an azimuth adjustment unit and a pitch adjustment unit installed at the output end of the azimuth adjustment unit; the azimuth adjustment unit is placed on a three-coordinate optical platform for developing, and the detector body is installed at the output end of the pitch adjustment unit via the socket assembly;

[0018] In S2, the detector is leveled by the pitch adjustment unit;

[0019] In S4, the relative spin position between the detector and the target is adjusted by the azimuth adjustment unit.

[0020] Furthermore, the multi-dimensional adjustment mechanism is a four-bar mechanism, comprising a central rotation axis, a central axis turntable and three pitch posture adjustment axes;

[0021] The central rotating shaft and the central shaft turntable constitute the azimuth adjustment unit, and the central shaft turntable is installed at the input end of the central rotating shaft;

[0022] The three pitch posture adjustment axes constitute the pitch adjustment unit, and the fixed ends of the three pitch posture adjustment axes are respectively installed on the output ends of the central rotating axis, and the output ends are all installed on the detector.

[0023] Furthermore, in S2, the clarity of any three-point differentiated targets etched on the non-photosensitive surface of the detector is judged using the microscope lens in the developing three-dimensional coordinate measuring instrument; if the clarity meets the set clarity condition, the heights of the three targets are measured using the microscope lens; if the clarity does not meet the set clarity condition, the focal depth of the microscope lens in the developing three-dimensional coordinate measuring instrument is adjusted and the clarity judgment is performed again;

[0024] The maximum deviation mean of the three target heights is defined as Δh, and the setting difference condition is: Δh∈(0.005)mm.

[0025] Furthermore, in S4, the width of the target stripe lines is consistent with the pixel size of the detector;

[0026] The spin position deviation is defined as Δx, and the difference condition is set as: Δx ≤ 1 pixel.

[0027] Furthermore, S5 is specifically:

[0028] S5.1. Use the three-dimensional coordinate measuring machine to adjust the position of the inspection lens so that the detector is located at the focal plane of the inspection lens;

[0029] S5.2. Adjust the three-dimensional coordinate measuring instrument to determine whether the detector can achieve pixel-level sampling of the target. If so, determine the focal plane position of the detector; if not, readjust the three-dimensional coordinate measuring instrument until the detector can achieve pixel-level sampling of the target.

[0030] Furthermore, in S6: based on the focal depth of the detection lens of the developing three-dimensional coordinate measuring instrument, the corresponding step size is set, and the clarity of the target image at the focal plane position of the detector is scanned and sampled to obtain the scanned and sampled image information. The scanned and sampled image information is imported into the Matlab software to construct the overfocus curve and the overfocus curve algorithm is used for machine vision interpretation.

[0031] Furthermore, when the detector is a multi-channel detector, it also includes S7:

[0032] Adjust the relative position between the detection lens and the detector photosensitive surface in the developing three-dimensional coordinate measuring machine, and implement the transmission function detection of the remaining channels of the detector in the same manner as steps S2 to S6.

[0033] Furthermore, when the detector is a low-light level detector, step S3 further includes:

[0034] Use a low-light illuminance meter to adjust the illuminance of the integrating sphere of the detection lens in the development three-dimensional coordinate measuring instrument to 10 -3 lux~10 -4 lux.

[0035] The beneficial effects of the present invention are:

[0036] 1. The use of a four-bar mechanism improves the adjustment accuracy of the relative position of the detector and the detection lens, and reduces the problem of insufficient transmission signal detection accuracy caused by improper installation;

[0037] 2. The use of a three-dimensional coordinate measuring instrument and a detection lens enables efficient calibration of the detector focal plane position, making the actual detection value closer to the true value result;

[0038] 3. The present invention realizes the rapid detection of the detector transmission function, effectively avoiding the risk of damage to the detector surface caused by traditional methods;

[0039] 4. By developing the high-precision displacement characteristics of the three-dimensional coordinate measuring instrument, rapid detection of multiple channels of the detector can be achieved;

[0040] 5. The present invention realizes the transmission function detection of batch detectors within a limited time.

[0041] 6. The present invention can complete the transmission function detection of the low-light detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a flow chart of an embodiment of the present invention;

[0043] Figure 2 This is a schematic diagram of a detector transmission function detection in an embodiment of the present invention;

[0044] Figure 3 Schematic diagram of the structure of the four-bar mechanism and the detector in an embodiment of the present invention;

[0045] Figure 4 is a sampling schematic diagram of a detector in an embodiment of the present invention;

[0046] Figure 5 Schematic diagram of differentiation targets in an embodiment of the present invention.

[0047] In the picture:

[0048] 1-Multi-dimensional adjustment mechanism; 11-Pitch position adjustment axis; 12-Center rotation axis; 13-Center axis turntable; 2-Detector body; 21-Sampling point one; 22-Sampling point two; 23-Sampling point three; 3-Socket assembly; 4-Development three-coordinate measuring instrument; 5-Detection lens; 6-Microscope lens; 7-Development three-coordinate optical platform. DETAILED DESCRIPTION

[0049] To further clarify the objectives, advantages, and features of the present invention, the following detailed description of a rapid, high-precision detection method for detector transmission signals proposed by the present invention is provided in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present invention will become even more apparent through the following detailed embodiments. It should be noted that the accompanying drawings are highly simplified and not to exact scale, and are intended solely to facilitate and clearly illustrate the objectives of the embodiments of the present invention. Furthermore, the structures shown in the drawings are often portions of actual structures.

[0050] Example 1

[0051] See also Figure 1 The present embodiment provides a method for rapid and high-precision detection of a detector transmission function, which mainly includes the following steps:

[0052] S1, see Figure 2 and Figure 3 , connect the detector to the multi-dimensional adjustment mechanism 1, and then place the connected detector and multi-dimensional adjustment mechanism 1 on the development three-coordinate optical platform 7.

[0053] See also Figure 2 The aforementioned detector is composed of a detector body 2 and a socket assembly 3; wherein the socket assembly 3 can realize the conversion of the photoelectric signal of the detector body; and a differentiation target is etched on the non-photosensitive surface of the detector.

[0054] Differentiate the target, and by cooperating with the microscope lens 6, realize the interpretation of the target image clarity, and further realize the horizontal adjustment of the detector through the multi-dimensional adjustment mechanism 1.

[0055] See also Figure 3 The multi-dimensional adjustment mechanism 1 is specifically a four-bar linkage, comprising a central rotation axis 12, a central axis turntable 13, and three pitch adjustment axes 11. The central rotation axis 12 and the central axis turntable 13 form an azimuth adjustment unit, enabling horizontal rotation adjustment. The central axis turntable 13 is mounted at the input end of the central rotation axis 12. The three pitch adjustment axes 11 form the pitch adjustment unit, with their fixed ends mounted at the output ends of the central rotation axis 12, each of which is mounted on the detector.

[0056] S2. Using any three points on the non-photosensitive surface of the detector as targets, use the microscope lens 6 and the four-bar mechanism to adjust the detector to a horizontal level.

[0057] S2.1. Use the microscope lens 6 in the developing three-dimensional coordinate measuring instrument 4 to sample and interpret the target clarity of any three points etched on the non-photosensitive surface of the detector. In this embodiment, see Figure 4 The three differentiation targets mentioned above are sampling point 1 21, sampling point 2 22 and sampling point 3 23; see Figure 5The aforementioned differentiation target is specifically the differentiation crosshairs. Clarity is determined by a pre-set machine vision recognition algorithm based on the depth of focus of the microscope lens 6 in the three-dimensional coordinate measuring instrument 4. Clarity is determined to determine whether the specified clarity conditions are met. If so, step S2.2 is executed. If not, the depth of focus of the microscope lens 6 in the three-dimensional coordinate measuring instrument 4 is adjusted and clarity is re-evaluated.

[0058] S2.2. Measure the heights of the three targets using the microscope lens 6 in the three-dimensional coordinate measuring instrument 4, and calculate the average of the maximum and minimum heights of the three sampled points as the adjustment reference.

[0059] S2.3. Based on the adjustment reference in S2.2, perform the first detector parallelism adjustment through the pitch direction posture adjustment axis 11 of the four-bar mechanism.

[0060] S2.4, repeat steps S2.1, S2.2, and S2.3;

[0061] S2.5. When the maximum deviation mean of the height difference of the three sampling points is Δh∈(0, 0.005) mm, the detector meets the leveling requirement.

[0062] S3. The detection lens 5 has a built-in stripe-line target, and the width of the line should be consistent with the pixel size of the low-light detector; the detector is powered on, and the relative position between the detection lens 5 installed on it and the detector photosensitive surface is adjusted through the development three-dimensional coordinate measuring instrument 4, so that the stripe-line target built into the detection lens 5 is clearly imaged by the detector, and the imaging clarity meets the set clarity requirements.

[0063] S4. Visually observe the relative spin position of the detector and target. Adjust the relative spin position of the detector and target using the multi-dimensional adjustment mechanism 1 to determine whether the spin position deviation satisfies the set deviation condition, Δx ≤ 1 pixel. If so, the parallelism adjustment between the detector and target is complete. If not, it indicates that there is an angle between the detector and the internal fringe line target of the detection lens 5, resulting in deformation of the fringe image formed by the detector. The relative spin position of the detector and target needs to be readjusted using the multi-dimensional adjustment mechanism 1 until the set deviation condition is met.

[0064] S5, using the developing three-dimensional coordinate measuring instrument 4 and the detection lens 5 to determine the focal plane position of the detector;

[0065] S5.1. Adjust the position of the detection lens 5 by using the three-dimensional coordinate measuring machine 4 so that the detector is located at the focal plane of the detection lens 5.

[0066] S5.2. Precise alignment of the target pattern and the detector pixels is essential for the incident light signal to accurately cover the pixel array, ensuring that the spatial frequency of the target pattern falls within the detector's effective sampling range, further enhancing the authenticity of contrast transmission. Therefore, this embodiment adjusts the development three-dimensional coordinate measuring instrument 4 to determine whether the detector can achieve pixel-level sampling of the target. If so, the detector's focal plane position is determined. If not, the development three-dimensional coordinate measuring instrument 4 is readjusted until the detector can achieve pixel-level sampling of the target.

[0067] S6. Based on the focal depth of the detection lens 5 of the developing three-dimensional coordinate measuring machine 4, set the corresponding step size and perform focus sampling to measure the clarity of the target image at the detector focal plane position. This sampling image information is then imported into Matlab software to construct an overfocus curve. Machine vision interpretation is performed using the overfocus curve algorithm, and the average interpretation is calculated to achieve detector transmission function detection.

[0068] Example 2

[0069] After completing step S6 of the first embodiment, by adjusting the relative precise displacement of the detection lens 5 in the developing three-dimensional coordinate measuring machine 4 and the detector photosensitive surface in the X direction and the Y direction, the remaining channel transmission function detection of the detector is realized in the same manner as steps S2 to S6 in the first embodiment.

[0070] Example 3

[0071] Steps S1 to S2, and steps 4 to 6 of this embodiment are the same as those of the first embodiment, except that, based on step S3 of the first embodiment, a low-light illuminometer is used to adjust the illuminance of the integrating sphere used for detecting the lens 5 in the developing three-dimensional coordinate measuring instrument 4 to 10 -3 lux~10 -4 lux, the same method as steps 4 to 6 in embodiment 1 is used to complete the low-light detector transmission function detection.

Claims

1. A method for rapid and high-precision detection of detector transmission function, characterized in that: The following steps are involved: S1, connecting the detector to the multi-dimensional adjustment mechanism (1), and then placing the connected detector and the multi-dimensional adjustment mechanism (1) on the development three-coordinate optical platform (7); S2. Leveling the detector using the multi-dimensional adjustment mechanism (1), taking any three points on the non-photosensitive surface of the detector as targets, and measuring the heights of the three targets using a developing three-coordinate measuring instrument (4); judging whether the average of the maximum deviations of the heights of the three targets meets the set difference condition, and if so, completing the leveling; if not, using the average of the maximum and minimum heights of the three points as the adjustment reference, re-leveling the detector using the multi-dimensional adjustment mechanism (1) until the set difference condition is met; S3, adjusting the relative position between the detection lens (5) mounted thereon and the detector photosensitive surface by developing a three-dimensional coordinate measuring instrument (4), so that the striped line-shaped target built into the detection lens (5) is imaged by the detector, and the image clarity meets the set clarity requirement; S4, adjusting the relative spin position of the detector and the target by the multi-dimensional adjustment mechanism (1), judging whether the spin position deviation satisfies the set deviation condition, and if so, completing the adjustment of the relative spin position of the detector and the target; if not, re-adjusting the relative spin position of the detector and the target by the multi-dimensional adjustment mechanism (1) until the set deviation condition is satisfied; S5, using the developing three-dimensional coordinate measuring instrument (4) and the detection lens (5) to determine the focal plane position of the detector; S6. Use the developing three-dimensional coordinate measuring instrument (4) to perform focus sampling on the clarity of the target image at the focal plane position of the detector to obtain the focus sampling image information, construct an overfocus curve based on the focus sampling image information and use the focus curve algorithm to perform machine vision interpretation, calculate the average value of the interpretation, and then realize the detector transmission function detection.

2. The method for rapid and high-precision detection of detector transmission function according to claim 1, characterized in that: In S1, the detector comprises a detector body (2) and a socket assembly (3); the multi-dimensional adjustment mechanism (1) comprises an azimuth adjustment unit and a pitch adjustment unit installed at the output end of the azimuth adjustment unit; the azimuth adjustment unit is placed on a developing three-coordinate optical platform (7), and the detector body (2) is installed at the output end of the pitch adjustment unit via the socket assembly (3); In S2, the detector is leveled by the pitch adjustment unit; In S4, the relative spin position between the detector and the target is adjusted by the azimuth adjustment unit.

3. The method for rapid and high-precision detection of detector transmission function according to claim 2, characterized in that: The multi-dimensional adjustment mechanism (1) is a four-bar mechanism, comprising a central rotation axis (12), a central axis turntable (13), and three pitch posture adjustment axes (11); The central rotating shaft (12) and the central shaft turntable (13) constitute the azimuth adjustment unit, and the central shaft turntable (13) is installed at the input end of the central rotating shaft (12); The three pitch posture adjustment shafts (11) constitute the pitch adjustment unit, and the fixed ends of the three pitch posture adjustment shafts (11) are respectively mounted on the output ends of the central rotation shaft (12), and the output ends are all mounted on the detector.

4. A method for rapid and high-precision detection of detector transmission function according to any one of claims 1 to 3, characterized in that: In S2, the microscope lens (6) in the developing three-dimensional coordinate measuring instrument (4) is used to judge the clarity of any three points of the differentiated targets etched on the non-photosensitive surface of the detector; if the clarity meets the set clarity condition, the height of the three targets is measured by the microscope lens (6); If the clarity does not meet the set clarity condition, the focal depth of the microscope lens (6) in the developing three-dimensional coordinate measuring instrument (4) is adjusted and the clarity is read again; The maximum deviation mean of the three target heights is defined as Δh, and the setting difference condition is: Δh∈(0, 0.005) mm.

5. The method for rapid and high-precision detection of detector transmission function according to claim 4, characterized in that: In S4, the width of the target stripe lines is consistent with the pixel size of the detector; The spin position deviation is defined as Δx, and the difference condition is set as: Δx ≤ 1 pixel.

6. A method for rapid and high-precision detection of detector transmission function according to claim 5, characterized in that: S5 is specifically: S5.

1. Adjust the position of the detection lens (5) by using the three-dimensional coordinate measuring instrument (4) so ​​that the detector is located at the focal plane of the detection lens (5); S5.

2. Adjust the developing three-dimensional coordinate measuring instrument (4) to determine whether the detector can achieve pixel-level sampling of the target. If so, determine the focal plane position of the detector; if not, readjust the developing three-dimensional coordinate measuring instrument (4) until the detector can achieve pixel-level sampling of the target.

7. A method for rapid and high-precision detection of detector transmission function according to claim 6, characterized in that: In S6: Based on the focal depth of the detection lens (5) of the developing three-dimensional coordinate measuring instrument (4), a corresponding step length is set, and the clarity of the target image at the focal plane position of the detector is scanned and sampled to obtain the scanned and sampled image information. The scanned and sampled image information is imported into Matlab software to construct an overfocus curve and a scanned and sampled focus curve algorithm is used for machine vision interpretation.

8. The method for rapid and high-precision detection of detector transmission function according to claim 1, characterized in that: When the detector is a multi-channel detector, it also includes S7: The relative position between the detection lens (5) and the photosensitive surface of the detector in the developing three-dimensional coordinate measuring instrument (4) is adjusted, and the remaining channel transmission function detection of the detector is realized in the same manner as steps S2 to S6.

9. The method for rapid and high-precision detection of detector transmission function according to claim 1, characterized in that: When the detector is a low-light detector, step S3 further includes: Use a low-light illuminance meter to adjust the illuminance of the integrating sphere of the detection lens (5) in the development three-dimensional coordinate measuring instrument (4) to 10 -3 lux~10 -4 lux.

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