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CN-122027787-A - Method and tool for calibrating ultra-long Jiao Jixin curve

CN122027787ACN 122027787 ACN122027787 ACN 122027787ACN-122027787-A

Abstract

The invention relates to the technical field of ultra-long focus movement calibration, in particular to an ultra-long Jiao Jixin curve calibration method and a tool, wherein the method comprises the steps of S1, dividing a plurality of calibration points to serve as zoom positions according to the zoom travel range of a zoom lens, S2, dynamically intercepting an image center area of an image shot at each zoom position according to intercepting proportion, S3, scanning a focusing position in the image center area and acquiring the image, calculating weighted image definition scores of the acquired image, S4, determining an optimal focusing position, forming a plurality of pairs with the corresponding zoom position, fitting data of all the calibration points to generate a zoom-focusing curve, storing the zoom-focusing curve as a calibration parameter table, and determining a target focusing position corresponding to the target zoom position through the calibration parameter table to realize whole-course focusing. The invention effectively improves the quality and stability of the image of the long focal end, thereby solving the core problem of inaccurate judgment of the image of the long focal end and improving the calibration precision.

Inventors

  • ZHU HE
  • LAN WEI
  • DAI YUMING
  • DAI JIATONG
  • Lu Guangpeng

Assignees

  • 杭州视辉科技有限公司

Dates

Publication Date
20260512
Application Date
20260410

Claims (10)

  1. 1. A method for calibrating an ultralong Jiao Jixin curve, comprising: s1, dividing a plurality of calibration points to serve as zoom positions according to a zoom travel range of a zoom lens; S2, presetting a zoom position range and a interception proportion range, calculating an interception proportion corresponding to each zoom position based on the zoom position range and the interception proportion range, and dynamically intercepting an image center area of a shot image of each zoom position according to the interception proportion; S3, scanning a focusing position of the central region of the image in the S2 with a self-adaptive step strategy and acquiring the image, and calculating a weighted image definition score of the acquired image based on a Sobel operator gradient method and a central and edge multi-region score; S4, determining an optimal focusing position based on the weighted image definition scores in the S3, forming a plurality of pairs with the corresponding zooming positions, fitting the data of all calibration points to generate a zooming-focusing curve, storing the zooming-focusing curve as a calibration parameter table, and determining a target focusing position corresponding to the target zooming position through the calibration parameter table to realize whole-course focusing.
  2. 2. The method for calibrating an ultralong Jiao Jixin curve according to claim 1, wherein step S2 specifically includes: The zoom position is set to be Z, , In order to be in the minimum zoom position, Is the maximum zoom position; Let the interception ratio be R, , For the minimum cut-out scale to be the smallest, Is the maximum interception proportion; the specific calculation formula of the interception ratio R (Z) of the image center area at the zoom position Z is as follows: ; wherein k is a nonlinear adjustment factor; Is the normalized zoom factor.
  3. 3. The method of claim 1, wherein calculating the weighted image sharpness score in step S3 comprises: dividing an acquired image into n-n image blocks, wherein the central area occupies n/2*n/2, and the bandwidths of the four edge areas occupy n/4; calculating image sharpness scores for regions of an acquired image I.e. the sum of the Sobel gradient energies of the image blocks in each region; presetting initial weights of all areas of an acquired image, and updating the weights according to gradient variation coefficients of image blocks in all areas to obtain updated weights of all areas; a weighted image sharpness score of the captured image is calculated based on the updated weights.
  4. 4. A method of calibrating an ultralong Jiao Jixin curve as recited in claim 3, wherein the initial weights of the regions of the acquired image are recorded as Update weights are noted as The specific calculation formula is as follows: ; Wherein, the Standard deviation of all image block gradients in region i; alpha epsilon [0,1] is a weight sensitivity coefficient or a noise suppression intensity parameter; T is a saturation cut-off threshold; The weighted image sharpness score is marked as S, and the specific calculation formula is as follows: ; 。
  5. 5. The method for calibrating an ultralong Jiao Jixin curve according to claim 3 or 4, wherein the initial weight of the central region of the preset acquired image is 0.5, and the initial weight of each region of four corners of the edge is 0.125.
  6. 6. The method of claim 1, wherein scanning the focal position and acquiring the image with the adaptive step strategy in step S3 comprises: S311, determining the focusing position range according to the current zoom position Minimum step size And maximum step size Presetting a grading threshold RT of a steep slope region to be 0.6, wherein a local slope saliency coefficient KT is 0.2, and a step size increase and decrease coefficient ST is 0.5; s312, determining the initial travelling direction, and executing bidirectional micro-step probing, namely, using the step length at the focusing position of the current scanning + ) 2 Proceeding distally and proximally to determine an initial direction of travel; S313, starting adaptive scanning, and calculating local slope of weighted image definition score of current focusing position P k Updating the maximum value of the score And score relative proportion ; ; ; ; Wherein, the A k-th focus position of the current scan; the last focusing position; Refers to the weighted image sharpness score at focus position k of the current scan; scoring the definition of the weighted image corresponding to the last focusing position; Preventing and removing zero; S314, adaptively calculating the next direction and step length based on And Judging a flat area and a steep slope area, wherein the step length of the flat area is increased by ST times of the current step length each time until the maximum step length When 0, the speed is reduced in the same direction, the step length is reduced by ST times of the current step length each time until the minimum step length is reached, and the step length is in a steep slope area When <0, the speed is reversely reduced, and the step length is executed to reduce the ST times of the current step length each time until the minimum step length; S315, checking the scanning direction changing times, including automatic reversing after reaching the boundary of the focusing position range, stopping scanning if the direction changing times are more than or equal to 2, otherwise repeating S313-S315; s316, determining and moving to a focusing position corresponding to the maximum weighted image definition score, and ending scanning.
  7. 7. The method of claim 6, wherein the step S314 is based on And The specific determination conditions for determining the flat region and the steep slope region are as follows: And (2) and ; The steep slope region is the steep slope region when the above condition is satisfied, otherwise the flat region.
  8. 8. An overlength Jiao Jixin curve calibration tool is characterized by comprising an upper computer and a lamp box (2), wherein one side in the lamp box (2) is provided with a target (1), the other side is provided with an overlength Jiao Jixin (4) to be calibrated, the upper computer is in wired or wireless connection with the overlength Jiao Jixin (4) to be calibrated, a specific focal length infinite equivalent mirror (3) is arranged between the overlength Jiao Jixin (4) to be calibrated and the target (1), and a triaxial adjusting frame (5) for adjusting the spatial position of the overlength Jiao Jixin (4) to be calibrated is arranged, so that the optical axis of the lens of the overlength Jiao Jixin (4) to be calibrated is precisely aligned with the optical axis of the specific focal length infinite equivalent mirror (3), and in the longest focal state, an image of the target (1) is positioned in the center of a picture.
  9. 9. The tool for calibrating the ultra-long Jiao Jixin curve according to claim 8, wherein the specific focal length infinity equivalent mirror (3) is a double-cemented lens structure, and comprises a front lens and a rear lens, wherein the front lens is a plano-concave lens, the rear lens is a biconvex lens, and the concave surface of the front lens is cemented with the convex surface of the rear lens.
  10. 10. The tool for calibrating the ultra-long Jiao Jixin curve according to claim 9, wherein the specific focal length infinity equivalent mirror (3) is a 3.6 m infinity equivalent mirror, wherein the refractive index n d =1.605 of the front lens, the abbe number V d =33.2 of the front lens, the ‌ curvature radius R 1 = infinity of the first plane of the front lens, the ‌ curvature radius R 2 =1560 mm of the second plane of the front lens, the ‌ diameter of the front lens being 113.2mm, the refractive index n d =1.517 of the rear lens, the abbe number V d =64.2 of the rear lens, the ‌ curvature radius R 3 =1560 mm of the first plane of the rear lens, the ‌ curvature radius R 4 =1585 mm of the second plane of the rear lens, and the ‌ diameter of the rear lens being 113.4mm.

Description

Method and tool for calibrating ultra-long Jiao Jixin curve Technical Field The invention relates to the technical field of ultra-long focus movement calibration, in particular to an ultra-long Jiao Jixin curve calibration method and a tool. Background During the production process of the ultra-long focus integrated movement, lens curve calibration is needed to ensure that the focus of the ultra-long focus integrated movement is kept clear (namely 'alignment Jiao Xing') during zooming). Patent document 202510887005.9 discloses a method and a system for correcting optical imaging zooming and point selection, which realize precise focusing by adopting self-adaptive step length in gradient rising direction and combining with dynamic adjustment of definition data to search strategies. However, for the overlength Jiao Jixin with the focal length exceeding 600mm, the core problem of inaccurate judgment of the picture at the long focal end exists, namely, in the long focal position, whether the picture reaches a clear state is difficult to accurately judge, so that the focusing precision is insufficient, the imaging is fuzzy, and the problem of poor alignment Jiao Xing is caused. Disclosure of Invention In view of the above, the invention provides a method and a tool for calibrating an ultra-long Jiao Jixin curve, which aim to solve the problems of inaccurate judgment of a long focal end picture and poor alignment Jiao Xing in the focusing process of an ultra-long focal movement in the prior art. In one aspect, the invention provides an ultra-long Jiao Jixin curve calibration method, which comprises the following steps: s1, dividing a plurality of calibration points to serve as zoom positions according to a zoom travel range of a zoom lens; S2, presetting a zoom position range and a interception proportion range, calculating an interception proportion corresponding to each zoom position based on the zoom position range and the interception proportion range, and dynamically intercepting an image center area of a shot image of each zoom position according to the interception proportion; S3, scanning a focusing position of the central region of the image in the S2 with a self-adaptive step strategy and acquiring the image, and calculating a weighted image definition score of the acquired image based on a Sobel operator gradient method and a central and edge multi-region score; S4, determining an optimal focusing position based on the weighted image definition scores in the S3, forming a plurality of pairs with the corresponding zooming positions, fitting the data of all calibration points to generate a zooming-focusing curve, storing the zooming-focusing curve as a calibration parameter table, and determining a target focusing position corresponding to the target zooming position through the calibration parameter table to realize whole-course focusing. Preferably, step S2 specifically includes: The zoom position is set to be Z, ,In order to be in the minimum zoom position,Is the maximum zoom position; Let the interception ratio be R, ,For the minimum cut-out scale to be the smallest,Is the maximum interception proportion; the specific calculation formula of the interception ratio R (Z) of the image center area at the zoom position Z is as follows: ; wherein k is a nonlinear adjustment factor; Is the normalized zoom factor. Preferably, the calculating of the weighted image sharpness score in step S3 includes: dividing an acquired image into n-n image blocks, wherein the central area occupies n/2*n/2, and the bandwidths of the four edge areas occupy n/4; calculating image sharpness scores for regions of an acquired image I.e. the sum of the Sobel gradient energies of the image blocks in each region; presetting initial weights of all areas of an acquired image, and updating the weights according to gradient variation coefficients of image blocks in all areas to obtain updated weights of all areas; a weighted image sharpness score of the captured image is calculated based on the updated weights. Preferably, the initial weights of the regions of the acquired image are recorded asUpdate weights are noted asThe specific calculation formula is as follows: ; Wherein, the Standard deviation of all image block gradients in region i; alpha epsilon [0,1] is a weight sensitivity coefficient or a noise suppression intensity parameter; T is a saturation cut-off threshold; The weighted image sharpness score is marked as S, and the specific calculation formula is as follows: ; 。 Preferably, the initial weight of the central area of the preset acquired image is 0.5, and the initial weight of each area of four corners of the edge is 0.125 respectively. Preferably, scanning the focus position with the adaptive step strategy and acquiring the image in step S3 includes: S311, determining the focusing position range according to the current zoom position Minimum step sizeAnd maximum step sizePresetting a grading threshold RT of a steep s