A method and apparatus for angle measurement based on a multi-element detector

Abstract

The application discloses a kind of angle measurement method and device based on multiple detector, solve the problem that the voltage information of the output of detector does not change when the light spot moves through the isolation area between adjacent pixels, thereby generating measurement error, affecting the accuracy of target light source angle measurement, due to the fact that the light spot only covers a single pixel in the existing optical system.The present application uses multiple detectors for angle measurement, which has the characteristics of large measurement field of view range, and then uses a large spot to avoid the problem that the output signal of the detector does not change when a small spot passes through the isolation area between adjacent pixels, improving the linearity of the calculation of the center coordinates of the light spot and reducing the complexity of the curve fitting algorithm.

Description

TECHNICAL FIELD

[0001] The present application relates to an angle measurement method and device, in particular to an angle measurement method and device based on a multi-element detector. BACKGROUND

[0002] The multi-element detector is a photoelectric detector composed of a plurality of photoelectric diodes arranged in a rectangular coordinate, which has the characteristics of fast response speed, high sensitivity and convenient use, and is widely used in optical systems such as tracking, positioning and collimation. Compared with the traditional four-image limited detector, the multi-element detector has a larger field of view due to the increase in the number of image elements, and can provide a larger active area for the optical system. Therefore, it is of great significance to study a multi-element detector angle measurement method with high precision for improving the performance of the optical measurement system.

[0003] In the traditional optical measurement system, the optical system images the target light source as a single image element size spot for measurement. However, due to the poor linearity of the circular spot center coordinate calculation method and the existence of the isolation area between the image elements, if the spot covers a single image element, i.e. the spot center coincides with the center of the single image element, the voltage information output by the multi-element detector will not change when the spot moves through the isolation area between the adjacent image elements. Therefore, the voltage data collected in this process will not change, and the result of calculating the angle of the target light source will also not change, resulting in measurement error and affecting the angle measurement accuracy of the target light source. SUMMARY

[0004] The present application aims to provide an angle measurement method and device based on a multi-element detector to solve the technical problem that the existing optical system has poor linearity when the spot only covers a single image element, resulting in no change in the voltage information output by the detector when the spot moves through the isolation area between the adjacent image elements, thereby causing measurement error and affecting the angle measurement accuracy of the target light source.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] An angle measurement method based on a multi-element detector, characterized in that it comprises the following steps:

[0007] Step 1: converging the target light source to the multi-element detector through the optical system to form a circular spot on the photosensitive surface of the multi-element detector, wherein the diameter d of the circular spot and the side length a of the image element satisfy: a < d < 2a; and the detection unit in the multi-element detector includes i rows x j columns, i ≥ 3, j ≥ 3;

[0008] Step 2: converting the optical signal into a voltage signal by the multi-element detector to obtain all row voltage signals U i and column voltage signals V j of the multi-element detector;

[0009] Step 3, obtaining the maximum row voltage signal U in all row voltage signals U i I and the maximum column voltage signal V in all column voltage signals V j J The corresponding positions of the two are the positions of the detected light spot center, and the position of the light spot center is recorded as the Ith row and the Jth column.

[0010] Step 4, calculating the light spot center coordinates:

[0011] If only the voltage values of the I-1th and Ith rows in the row voltage signals U i are non-default voltage values (the default voltage value is the voltage value output by the row and column without a light spot), and only the voltage values of the J-1th and Jth columns in the column voltage signals V j are non-default voltage values, then the light spot center coordinates (x, y) are:

[0012]

[0013] If only the voltage values of the I+1th and Ith rows in the row voltage signals U i are non-default voltage values, and only the voltage values of the J+1th and Jth columns in the column voltage signals V j are non-default voltage values, then the light spot center coordinates (x, y) are:

[0014]

[0015] If only the voltage values of the I-1th, Ith and I+1th rows in the row voltage signals U i are non-default voltage values, and only the voltage values of the J-1th, Jth and J+1th columns in the column voltage signals V j are non-default voltage values, then the light spot center coordinates (x, y) are:

[0016] x = (x1 + x2) / 2 + J * d;

[0017] y = (y1 + y2) / 2 + I * d;

[0018] wherein,

[0019] Step 5, calculating the horizontal angle α and the vertical angle β between the target light source and the photosensitive surface of the multi-element detector:

[0020]

[0021] wherein, f is the distance from the photosensitive surface of the multi-element detector to the imaging surface of the optical system.

[0022] ​​Further, the method further comprises: step 6, calibrating the measured angles alpha and beta and the real angles by using a segmented curve fitting method, obtaining a relationship function between the measured angles and the real angles, and obtaining the real angles of the target light source in real time based on the relationship function and the measured angles.

[0023] Further, in step 1, i = 8 and j = 8.

[0024] An angle measuring device based on a multi-element detector, used to implement the above-mentioned angle measuring method based on a multi-element detector, and the special features are that the device comprises an optical system, a multi-element detector, a signal acquisition unit and a signal processing unit.

[0025] The optical system is arranged at the detection end of the multi-element detector, and is used to converge the target light source to the multi-element detector, so that a circular light spot is formed on the photosensitive surface of the multi-element detector, and the diameter d of the circular light spot and the side length a of the pixel satisfy: a < d < 2a.

[0026] The multi-element detector comprises i rows and j columns of detection units, and is used to convert the light signal into a voltage signal, and i >= 3 and j >= 3.

[0027] The acquisition end of the signal acquisition unit is connected with the output end of the multi-element detector, and is used to receive the voltage signal and send the voltage signal to the signal processing unit.

[0028] The signal processing unit is connected with the output end of the signal acquisition unit, and is used to calculate the angle between the target light source and the photosensitive surface of the multi-element detector according to the received voltage signal.

[0029] Further, the multi-element detector comprises 8x8 detection units.

[0030] The present application has the following beneficial effects:

[0031] The present application uses a multi-element detector to measure the angle, has the characteristics of a large measurement field of view, and uses a large light spot to avoid the problem that the output signal of the detector does not change when the small light spot passes through the isolation area between adjacent pixels, improves the linearity of the calculation of the center coordinates of the circular light spot, reduces the complexity of the curve fitting algorithm, and at the same time, when the light spot edge is in the isolation area, the average value is taken to improve the light spot coordinate measurement accuracy, and provides strong support for the angle calibration of the target light source. The present application can provide strong support for the guidance and recovery of underwater unmanned vehicles, robot path planning management and the like. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a structural schematic diagram of an embodiment of an angle measuring device based on a multi-element detector of the present application;

[0033] Figure 2is a structural schematic diagram of a multi-element detector in an embodiment of the present application;

[0034] Figure 3 is a relationship diagram of a light spot coordinate and a pixel center in an embodiment of the present application;

[0035] Figure 4 is a relationship curve diagram of a measured angle and a real angle in an embodiment of the present application.

[0036] Reference signs:

[0037] 1-target light source, 2-optical system, 3-multi-element detector, 4-signal acquisition unit, 5-data processing unit. DETAILED DESCRIPTION

[0038] The technical solutions of the present application will be described clearly and completely in combination with the drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0039] An angle measurement device based on a multi-element detector is provided in an embodiment of the present application, as shown in the figure, which comprises an optical system 2, a multi-element detector 3, a signal acquisition unit 4 and a signal processing unit 5. Figure 1

[0040] The optical system 2 is arranged at a detection end of the multi-element detector 3, and is used to converge light of a target light source 1 to the multi-element detector 3, so that a circular light spot is formed on a light-sensitive surface of the multi-element detector 3, and a diameter d of the circular light spot and a side length a of each pixel satisfy: a < d < 2a; in this embodiment, d = 1.5a is preferred. The multi-element detector 3 comprises i rows x j columns of detection units, i ≥ 3, j ≥ 3; in this embodiment, i = 8 and j = 8 are preferred. The acquisition end of the signal acquisition unit 4 is connected with the output end of the multi-element detector 3, and the signal processing unit 5 is connected with the output end of the signal acquisition unit 4.

[0041] The working process of the above angle measurement device is as follows:

[0042] Step 1, converging the target light source 1 to the multi-element detector 3 through the optical system 2, as shown in the figure, so that a circular light spot is formed on the light-sensitive surface of the multi-element detector 3; Figure 2

[0043] Step 2, converting the light signal into a voltage signal by the multi-element detector 3, and acquiring all row voltage signals U i and column voltage signals V j output by the multi-element detector 3;

[0044] ​​Step 3, obtain the maximum row voltage signal U in all row voltage signals U i I and the maximum column voltage signal V in all column voltage signals V j J Then the corresponding positions are the positions of the detected light spot center, and the positions of the light spot center are recorded as the Ith row and the Jth column.

[0045] Step 4, as shown in Figure 3 , calculate the light spot center coordinates:

[0046] If only the voltage values of the I-1th and Ith rows in the row voltage signals U i are non-default voltage values (the default voltage value is the voltage value output by the row and column without a light spot), and only the voltage values of the J-1th and Jth columns in the column voltage signals V j are non-default voltage values, then the light spot center coordinates (x, y) are:

[0047]

[0048] If only the voltage values of the I+1th and Ith rows in the row voltage signals U i are non-default voltage values, and only the voltage values of the J+1th and Jth columns in the column voltage signals V j are non-default voltage values, then the light spot center coordinates (x, y) are:

[0049]

[0050] If only the voltage values of the I-1th, Ith and I+1th rows in the row voltage signals U i are non-default voltage values, and only the voltage values of the J-1th, Jth and J+1th columns in the column voltage signals V j are non-default voltage values, then the light spot center coordinates (x, y) are:

[0051] x = (x1 + x2) / 2 + J * d;

[0052] y = (y1 + y2) / 2 + I * d;

[0053] Wherein,

[0054] When the light spot edge is in the isolation area, the average value is taken to improve the measurement accuracy of the light spot coordinates.

[0055] Step 5, calculate the horizontal angle α and the vertical angle β between the target light source and the photosensitive surface of the multi-element detector:

[0056]

[0057] ​​Wherein, f is the distance from the photosensitive surface of the multi-element detector to the imaging surface of the optical system.

[0058] Step 6, the above angle measuring device is arranged on the turntable, the target light source 1 is fixed on the lifting platform, the height of the lifting platform is adjusted, the light spot is in the center of the first row of image elements, the position is 0° position, the turntable is rotated in positive and negative directions respectively every certain angle, the first row of push scanning is completed, the lifting platform is adjusted, and the second row is pushed and scanned; each rotation and lifting is repeated from step 1 to step 5, the horizontal direction included angle α and the vertical direction included angle β corresponding to all rows and columns are obtained, and the corresponding real horizontal direction included angle θ and the vertical direction included angle are obtained one by one Then the relationship between the measured angles α and β and the real angles is calibrated by the piecewise curve fitting method, and the relationship between the measured angles and the real angles is obtained:

[0059] θ=f1(α);

[0060]

[0061] The curve diagram is as shown in Figure 4

[0062] Based on the above and the real-time measured angle, the real angle of the target light source is obtained.

[0063] It should be noted that for the calibration of the channel switching region (i.e. the isolation region between adjacent image elements), the angles in a range before and after channel switching are collected for calibration, so that there is a certain overlapping region between the two regions, and the average value of the calculation results of the two regions is used as the real angle in actual use. The calibration process needs to calibrate each row and each column in the optical field of view range, and data is collected every certain angle.

[0064] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any change or replacement within the technical scope disclosed in the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.​

Claims

1. An angle measurement method based on a multi-element detector, characterized in that, Includes the following steps: Step 1: Focus the target light source onto the multi-element detector through an optical system, so that it forms a circular light spot on the photosensitive surface of the multi-element detector. The diameter d of the circular light spot and the side length a of the pixel satisfy: a < d < 2a; The detection unit in the multi-element detector includes i rows × j columns, i ≥ 3, j ≥ 3; Step 2: The multi-element detector converts the optical signal into a voltage signal, and acquires all the line voltage signals U output by the multi-element detector. i Sum and column voltage signal V j ; Step 3: Obtain all row voltage signals U i The maximum row voltage signal U in I and all column voltage signals V j The maximum column voltage signal V in J Then the corresponding positions of the two are the pixel positions of the detected light spot center, and the pixel positions of the light spot center are denoted as the I-th row and the J-th column; Step 4: Calculate the coordinates of the light spot center: If the voltage signal U i Only the voltage values ​​in rows I-1 and I are non-default voltage values, and the column voltage signal V j If only the voltage values ​​in columns J-1 and J are not the default voltage values, then the coordinates (x, y) of the light spot center are: If the voltage signal U i Only the voltage values ​​in rows I+1 and I are non-default voltage values, and the column voltage signal V j If only the voltage values ​​in columns J+1 and J are not the default voltage values, then the coordinates (x, y) of the light spot center are: If the voltage signal U i Only the voltage values ​​in rows I-1, I, and I+1 are non-default voltage values, and the column voltage signal V j If only the voltage values ​​in columns J-1, J, and J+1 are not the default voltage values, then the coordinates (x, y) of the light spot center are: x = (x1 + x2) / 2 + J*d; y = (y1 + y2) / 2 + I*d; in, Step 5: Calculate the angle α between the target light source and the photosensitive surface of the multi-element detector in the horizontal direction and the angle β between them in the vertical direction. Where f is the distance from the photosensitive surface of the multi-element detector to the imaging surface of the optical system.

2. The angle measurement method based on multiple detectors according to claim 1, characterized in that, Also includes: Step 6: Calibrate the measured angles α and β with the true angle using the piecewise curve fitting method, obtain the relationship function between the measured angle and the true angle, and obtain the true angle of the target light source in real time based on the relationship function and the measured angle.

3. The angle measurement method based on a multi-element detector according to claim 1 or 2, characterized in that, In step 1: i = 8, j = 8.

4. An angle measurement device based on a multi-element detector, used to implement the angle measurement method based on a multi-element detector as described in any one of claims 1-3, characterized in that: It includes an optical system (2), a multi-element detector (3), a signal acquisition unit (4), and a signal processing unit (5); The optical system (2) is set at the detection end of the multi-element detector (3) to focus the target light source (1) onto the multi-element detector (3) so that it forms a circular light spot on the photosensitive surface of the multi-element detector (3). The diameter d of the circular light spot and the side length a of the pixel satisfy: a < d < 2a. The multi-element detector (3) includes i rows × j columns of detection units, which are used to convert optical signals into voltage signals, i≥3, j≥3; The acquisition end of the signal acquisition unit (4) is connected to the output end of the multi-element detector (3) to receive the voltage signal and send it to the signal processing unit (5); The signal processing unit (5) is connected to the output end of the signal acquisition unit and is used to calculate the angle between the target light source (1) and the photosensitive surface of the multi-element detector based on the received voltage signal.

5. The angle measurement device based on a multi-element detector according to claim 4, characterized in that: The multi-element detector (3) includes 8×8 detection units.

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