Distorted laser spot center positioning device based on square inscribed circle

Abstract

The utility model relates to the distortion laser spot center positioning device based on square incircle. System includes transmitting end, receiving end and processing module. Laser output beam in transmitting end is reflected through beam expander and fast mirror, and the closed loop stabilization of beam displacement and angle is realized through six -dimensional adjusting frame linkage grating ruler and autocollimator. Receiving end gathers the light spot through receiving antenna, and the image is output to processing module by imaging sensor after filtering out the noise by narrow -band optical filter. Processing module executes gray scale normalization, edge detection, boundary point extreme value calculation (obtains horizontal width and vertical height) in proper order;According to the width and height size relation, the minimum circumscribed square is generated by the length of side adaptive selection;Based on square boundary extreme point, the center coordinates and radius of incircle are calculated, and are taken as the light spot center position and characteristic parameter output. The scheme effectively solves the real -time high -precision positioning problem under the light spot distortion and environmental interference, and is suitable for laser guidance, optical precision alignment and the field.

Description

Technical Field

[0001] This utility model belongs to the field of free space optical communication technology, and in particular relates to a distortion laser spot center positioning device based on a square inscribed circle. Background Technology

[0002] Free-space optical communication (FSO) has become a core transmission technology in key areas such as satellite links and military communications due to its advantages of high bandwidth, strong anti-interference, and confidentiality. However, its laser beam is affected by turbulence, temperature changes, and aerosol disturbances during atmospheric transmission, which causes wavefront distortion, irregular shape, and center of gravity drift of the light spot at the receiving end, seriously damaging the stability of communication.

[0003] To suppress the effects of light spot distortion, common existing techniques include localization algorithms:

[0004] Traditional centroid method: sensitive to light spot intensity distribution, and has significant positioning error in fragmented light spots caused by strong turbulence;

[0005] Circle fitting method: relies on complete closed contours and has poor tolerance to edge noise and local missing parts;

[0006] Hough transform method: high computational complexity, and its real-time performance is difficult to meet the requirements of high-speed communication.

[0007] Especially in highly turbulent environments, the above methods generally expose three major bottlenecks:

[0008] Insufficient precision: The asymmetry of the distorted spot causes the centroid to deviate from the physical center;

[0009] Weak robustness: Contour extraction fails under noise interference, and the failure rate of circle fitting increases sharply;

[0010] Excessive latency: The software algorithm has high processing latency, which cannot match the real-time requirements of the active beam correction system.

[0011] Therefore, there is an urgent need for a spot center localization scheme that combines hardware acceleration capabilities, adaptive distortion correction, and microsecond-level response to support the construction of a highly reliable FSO system. Utility Model Content

[0012] The purpose of this invention is to provide a distortion laser spot center positioning device based on a square inscribed circle, in order to solve the problems existing in the prior art. To achieve the above-mentioned objective, the technical solution adopted by this invention is as follows:

[0013] A distortion laser spot center positioning device based on a square inscribed circle includes a transmitter, a receiver, and a processing module; the transmitter is connected to the receiver, and the receiver is connected to the processing module.

[0014] The processing module includes a preprocessing unit, an edge detection unit, an extreme point calculation unit, a geometric calculation core, and an output unit; the preprocessing module is communicatively connected to the edge detection unit, the edge detection unit is communicatively connected to the extreme point calculation unit, the extreme point calculation unit is communicatively connected to the geometric calculation core, and the geometric calculation core is communicatively connected to the output unit.

[0015] The preprocessing unit has a built-in grayscale normalization circuit;

[0016] The edge detection unit outputs the coordinates of the boundary points;

[0017] The extreme point calculation unit calculates the horizontal width w and the vertical height h;

[0018] The geometric calculation core includes a side length selection unit and a center coordinate generation unit;

[0019] The output unit transmits the center coordinates and radius of the circle.

[0020] Furthermore, the transmitting end includes a laser, a beam expander, a fast reflector, a fixed base, and an adjustment component; the output end of the laser is detachably connected to the beam expander, the adjustment component is equipped with the laser, the fixed base is equipped with the fast reflector, and the adjustment component is connected to the fixed base.

[0021] Furthermore, the adjustment components include an autocollimator, a grating ruler reading head, a six-dimensional adjustment frame, a grating ruler body, and a controller; the six-dimensional adjustment frame is detachably mounted on the fixed base, and the beam expander is threadedly connected to the six-dimensional adjustment frame; the autocollimator is detachably mounted on the fixed base and is located on the optical axis of the beam expander; the grating ruler body is detachably mounted on the base plate of the six-dimensional adjustment frame; the grating ruler reading head is detachably mounted on the fast-reflection mirror base; and the grating ruler reading head and the six-dimensional adjustment frame are communicatively connected to the controller.

[0022] Furthermore, the receiving end includes a receiving antenna, a narrowband filter, and an imaging sensor; the receiving antenna is detachably connected to the narrowband filter, the narrowband filter is connected to the imaging sensor, and the imaging sensor is connected to the preprocessing unit.

[0023] Furthermore, the preprocessing unit integrates a dual-port RAM cache chip, and the grayscale normalization circuit employs a linear converter.

[0024] Furthermore, the edge detection unit employs a convolution processor, whose input pins are connected to the output pins of the preprocessing unit.

[0025] Furthermore, the extreme point calculation unit includes:

[0026] X-direction extreme value detector, scans the x-coordinate of boundary points;

[0027] Y-direction extreme value detector, scans the y-coordinate of boundary points;

[0028] A subtraction counter that calculates the width w and height h.

[0029] Furthermore, the geometric calculation core includes:

[0030] Data selector, outputs side length;

[0031] The adder and shift register are used to obtain the coordinates of the center of the circle.

[0032] This invention has the following advantages: It effectively suppresses environmental disturbances and ensures the stability of the emitted beam through an active beam stabilization system (fast-reflecting mirror combined with a six-dimensional adjustment frame, grating ruler closed-loop feedback, and autocollimator angle reference); the receiving end uses a narrowband filter to improve the imaging signal-to-noise ratio; the processing module uses dedicated hardware circuits (grayscale normalization, convolution edge detection, comparator extreme value calculation, data selector, and adder geometric generation) to achieve high-speed processing, and combines it with an adaptive square inscribed circle algorithm to finally achieve high-precision, high-speed, and strong anti-interference beam center positioning. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of this utility model;

[0034] Figure 2 This is a flowchart of the positioning method;

[0035] Figure 3 It is a schematic diagram of the distorted spot outline, the smallest bounding rectangle, and the square inscribed circle structure (the cross intersection is the center of the circle). Detailed Implementation

[0036] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0037] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0038] like Figure 1-3 As shown, the system includes a transmitter 1, a receiver 3, and a processing module 4. The transmitter 1 is connected to the receiver 3, and the receiver 3 is connected to the processing module 4. The processing module 4 includes a preprocessing unit 401, an edge detection unit 402, an extreme point calculation unit 403, a geometric calculation core 404, and an output unit 405. The preprocessing module 4 is communicatively connected to the edge detection unit 402, the edge detection unit 402 is communicatively connected to the extreme point calculation unit 403, the extreme point calculation unit 403 is communicatively connected to the geometric calculation core 404, and the geometric calculation core 404 is communicatively connected to the output unit 405. The preprocessing unit 401 has a built-in grayscale normalization circuit. The edge detection unit 402 outputs the coordinates of boundary points. The extreme point calculation unit 403 calculates the horizontal width w and the vertical height h. The geometric calculation core 404 includes a side length selection unit and a center coordinate generation unit. The output unit 405 transmits the center coordinates and radius. First, transmitter 1 emits a laser beam, which is received by receiver 3. The received distorted light spot image provides raw data for subsequent localization. The received image undergoes grayscale normalization to unify the grayscale values ​​within a preset range, ensuring stability and consistency in subsequent processing. Next, an edge detection algorithm is used to extract the edge contour information of the light spot, calculate and obtain the coordinates of all boundary points of the light spot boundary, and then extract the extreme points among the boundary points to calculate the side length of the minimum bounding rectangle. Subsequently, the width w in the horizontal direction and the height h in the vertical direction of the boundary points are calculated respectively, and the relationship between the width w and the height h is determined. If w is greater than h, then h is used as the side length of the square; otherwise, w is used as the side length of the square. Based on the determined square, the coordinates of the center of its inscribed circle are calculated as the estimated position of the light spot center, and the radius of the inscribed circle is calculated as one of the feature parameters of the light spot. Finally, the calculated position of the light spot center and the radius of the inscribed circle are output, completing the entire light spot center localization process.

[0039] like Figure 1As shown, the transmitting end 1 includes a laser 101, a beam expander 102, a fast reflector 103, a fixed base 104, and an adjustment component 2; the output end of the laser 101 is connected to the beam expander 102 through a precision threaded interface or flange, the laser 101 is mounted on the adjustment component 2, the fast reflector 103 is mounted on the fixed base 104 by means of rigid epoxy adhesive bonding and heat sink, and the adjustment component 2 is connected to the fixed base 104. The adjustment component 2 includes an autocollimator 201, a grating ruler reading head 202, a six-dimensional adjustment frame 203, a grating ruler body 204, and a controller 205. The six-dimensional adjustment frame 203 is detachably mounted on the fixed base 104. The beam expander 102 is fixed to the six-dimensional adjustment frame 203 by flange bolts. The autocollimator 201 is detachably mounted on the fixed base 104 and is located on the optical axis of the beam expander 102. The grating ruler body 204 is bonded to the base plate of the six-dimensional adjustment frame 203 by zero-expansion adhesive. The grating ruler reading head 202 is mounted on the base of the fast-reflecting mirror 103 via a magnetic mounting seat. The grating ruler reading head 202 and the six-dimensional adjustment frame 203 are communicatively connected to the controller 205. The six-dimensional adjustment frame 203 provides XYZ translation and rotation degrees of freedom for the beam expander 102. The fast-reflecting mirror 103 ensures the absolute stability of the reflecting surface. The grating ruler reading head 202 monitors the distance between the beam expander 102 and the fast-reflecting mirror 103 in real time. The grating ruler body 204 establishes a displacement reference benchmark. The six-dimensional adjustment frame 203 receives displacement compensation commands (the reading of the grating ruler reading head 202 is fed back to the controller 205, which controls the displacement). The autocollimator 201 serves as the absolute benchmark for angle measurement, monitoring the angle of the beam output from the beam expander 102. The optical axis of the autocollimator 201 must be strictly parallel to the beam output from the beam expander. It should be noted that the laser 101 → beam expander 102 → fast reflector 103 reflector surface → free space → receiving antenna 301 are all on the same straight line; the output beam of beam expander 102 → the field of view center of autocollimator 201 are all on the same straight line; the grating ruler body 204 → the movement trajectory of grating ruler reading head 202 → the mounting base of fast reflector 103 are all on the same straight line.

[0040] Furthermore, the receiving end 3 includes a receiving antenna 301, a narrowband filter 302, and an imaging sensor 303; the receiving antenna 301 is detachably connected to the narrowband filter 302, the narrowband filter 302 is connected to the imaging sensor 303, and the imaging sensor 303 is connected to the preprocessing unit 401.

[0041] It is important to note that the preprocessing unit 401 integrates a dual-port RAM cache chip (IS61WV102416BLL), and the grayscale normalization circuit uses a linear converter (AD538). The edge detection unit 402 uses a convolution processor, and its input pins are connected to the output pins of the preprocessing unit 401.

[0042] In addition, the extreme point calculation unit 403 includes: an X-direction extreme point detector (SN74LS682 comparator chip) that scans the x-coordinate of the boundary point; a Y-direction extreme point detector (SN74LS682 comparator chip) that scans the y-coordinate of the boundary point; and the width w and height h are obtained by calculating the difference between extreme points using a subtraction counter (CD4029).

[0043] Furthermore, the geometric calculation core 404 includes: a data selector (74HC157) that outputs the side length L=h when w>h;

[0044] When w ≤ h, output the side length L = w;

[0045] The center coordinate generation unit is implemented using an adder (CD4008) and a shift register (CD4035):

[0046] The x-coordinate of the center of the circle = (x_min + L / 2),

[0047] The y-coordinate of the center of the circle is (y_min + L / 2).

[0048] x_min = Left boundary position of the light spot: the minimum coordinate value of all edge points in the horizontal direction;

[0049] y_min = Lower boundary position of the light spot: the minimum coordinate value of all edge points in the vertical direction.

[0050] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Any modifications, alterations, alterations, or substitutions made by those skilled in the art to the technical solutions of the present utility model without departing from the spirit of the present utility model shall fall within the protection scope defined by the claims of the present utility model.

Claims

1. A device for locating the center of a distorted laser spot based on a square inscribed in a circle, characterized in that: It includes a transmitter (1), a receiver (3), and a processing module (4); the transmitter (1) is connected to the receiver (3), and the receiver (3) is connected to the processing module (4). The processing module (4) includes a preprocessing unit (401), an edge detection unit (402), an extreme point calculation unit (403), a geometric calculation core (404), and an output unit (405); the processing module (4) is communicatively connected to the edge detection unit (402), the edge detection unit (402) is communicatively connected to the extreme point calculation unit (403), the extreme point calculation unit (403) is communicatively connected to the geometric calculation core (404), and the geometric calculation core (404) is communicatively connected to the output unit (405); The preprocessing unit (401) has a built-in grayscale normalization circuit; The edge detection unit (402) outputs the coordinates of the boundary points; The extreme point calculation unit (403) calculates the horizontal width w and the vertical height h; The geometric calculation core (404) includes a side length selection unit and a center coordinate generation unit; The output unit (405) transmits the center coordinates and radius.

2. The distortion laser spot center positioning device based on a square inscribed circle according to claim 1, characterized in that: The transmitting end (1) includes a laser (101), a beam expander (102), a fast reflector (103), a fixed base (104), and an adjustment component (2); the output end of the laser (101) is detachably connected to the beam expander (102), the adjustment component (2) is provided with the laser (101), the fixed base (104) is provided with the fast reflector (103), and the adjustment component (2) is connected to the fixed base (104).

3. The distortion laser spot center positioning device based on a square inscribed circle according to claim 2, characterized in that: The adjustment component (2) includes an autocollimator (201), a grating ruler reading head (202), a six-dimensional adjustment frame (203), a grating ruler body (204), and a controller (205). The six-dimensional adjustment frame (203) is detachably mounted on the fixed base (104). The beam expander (102) is threaded onto the six-dimensional adjustment frame (203). The autocollimator (201) is detachably mounted on the fixed base (104). The autocollimator (201) is located on the optical axis of the beam expander (102). The grating ruler body (204) is detachably mounted on the base plate of the six-dimensional adjustment frame (203). The grating ruler reading head (202) is detachably mounted on the base of the fast-reflecting mirror (103). The grating ruler reading head (202) and the six-dimensional adjustment frame (203) are communicatively connected to the controller (205).

4. The distortion laser spot center positioning device based on a square inscribed circle according to claim 1, characterized in that: The receiving end (3) includes a receiving antenna (301), a narrowband filter (302), and an imaging sensor (303); the receiving antenna (301) is detachably connected to the narrowband filter (302), the narrowband filter (302) is connected to the imaging sensor (303), and the imaging sensor (303) is connected to the preprocessing unit (401).

5. The distortion laser spot center positioning device based on a square inscribed circle according to claim 1, characterized in that: The preprocessing unit (401) integrates a dual-port RAM cache chip, and the grayscale normalization circuit uses a linear converter.

6. The distortion laser spot center positioning device based on a square inscribed circle according to claim 1, characterized in that: The edge detection unit (402) employs a convolution processor, and its input pins are connected to the output pins of the preprocessing unit (401).

7. The distortion laser spot center positioning device based on a square inscribed circle according to claim 1, characterized in that: The extreme point calculation unit (403) includes: X-direction extreme value detector, scans the x-coordinate of boundary points; Y-direction extreme value detector, scans the y-coordinate of boundary points; A subtraction counter that calculates the width w and height h.

8. The distortion laser spot center positioning device based on a square inscribed circle according to claim 1, characterized in that: The geometric calculation core (404) includes: Data selector, outputs side length; The adder and shift register are used to obtain the coordinates of the center of the circle.

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