Optical imaging zoom point selection correction method and system

Abstract

The present invention discloses a method and system for optical imaging zoom point selection correction. Through the peak point tracking algorithm and offset vector calculation in the second stage, the deviation between the theoretical model and the actual lens characteristics is corrected in real time, effectively solving the individual error problem caused by lens assembly tolerance, material refractive index difference, etc. The layered sampling strategy in the first stage is combined with the slope interpolation in the third stage to fill the untested points in the theoretical curve, generate a high-precision focus curve, cover the full zoom range, and avoid local focus failure caused by traditional uniform sampling. The third stage introduces median filtering to filter outlier data, eliminate curve jitter caused by test noise or mechanical vibration, output a smooth zoom focus curve, improve the anti-interference ability in actual control, avoid frequent jitter of the focus motor, and dynamically adjust the search strategy in combination with clarity data to quickly lock the actual peak point, avoiding overshoot or slow convergence caused by traditional fixed step size.

Description

Technical Field

[0001] The present invention relates to the field of monitoring technology, and in particular to an optical imaging zoom point selection correction method and system. Background Art

[0002] Deficiencies in existing products and technology fields:

[0003] In today's surveillance landscape, varifocal network cameras, equipped with complex optical zoom lens systems with software-programmable control, enable efficient monitoring of scenes across a wide range of distances and diverse viewing angles. To ensure that the camera consistently captures high-definition images during optical zoom operations, a sophisticated zoom tracking control strategy must be implemented.

[0004] In the existing technology, no practical solution has yet been proposed or implemented to address the inaccuracy of focusing cameras that rely on a pre-set theoretical focus trajectory during operation. This technical difficulty highlights the challenge of ensuring that optical imaging systems can consistently and stably deliver high-definition images in a dynamically changing working environment.

[0005] In summary, an optical imaging zoom point selection correction method and system are needed to address the shortcomings of the existing technology. Summary of the Invention

[0006] In view of the deficiencies in the prior art, the present invention provides an optical imaging zoom point selection correction method and system, aiming to solve the above problems.

[0007] To achieve the above-mentioned object, the present invention provides the following technical solution: a method for correcting the zoom point selection of optical imaging, comprising the following steps:

[0008] Step S1: Data acquisition, through primary sampling and reduced step sampling, imaging data sampling is performed on the optical zoom range with three-level sampling points set, and the acquired data is integrated into a multi-dimensional matrix;

[0009] Step S2: Calculating the theoretical focus peak point coordinates using multi-dimensional matrix data and gradient descent method, and the control system drives the zoom motor and focus group to move to the theoretical focus peak point coordinates;

[0010] Step S3: Adaptive step search, set the initial step size, move in the gradient ascending direction and collect picture clarity data, and when the clarity reaches the peak, lock the current coordinate as the actual zoom position;

[0011] Step S4: reverse optimization and error calculation, performing reverse search to determine the peak point of the defocus tolerance boundary, calculating the offset vector △Z between the actual peak point and the theoretical value, and realizing dynamic compensation of nonlinear error through the offset;

[0012] Step S5: Bring the offset ΔZ into the system, narrow the calibration points, obtain the focus peak points of L discrete focus points through the peak point tracking algorithm, and calculate the slopes of adjacent points to fill in the focus points of the missing test points in the theoretical curve;

[0013] Step S6: Use median filtering to process the discrete data in the fitting curve to generate a smooth zoom focus curve with the required accuracy, thereby achieving zoom point correction.

[0014] Optionally, the reference points of the three-level sampling points within the optical zoom range in step S1 are the wide-angle end, the medium-short focal length, and the telephoto end. The primary sampling collects data in a fixed step size, and the encrypted sampling collects data in an equally divided fixed step size.

[0015] Optionally, the adaptive step size search in step S3 is performed in the following manner:

[0016] Move in the direction of gradient ascent with an initial step size, collecting picture clarity data after each movement. When the clarity data shows an upward and then downward trend, in order to reach the peak area, lock the current coordinate as the actual zoom position.

[0017] Optionally, the offset vector in step S4 is calculated in the following manner:

[0018] Compare the actual measured two peak point coordinates (Zv3, Zf1), (Zv4, Zf2) with the theoretical values ​​of the corresponding focus positions (Zv1, Zf1), (Zv2, Zf2) to obtain two offsets △Zv1, △Zv2. Calculate the offset vector △Zv by averaging the offsets.

[0019] △Zv=(△Zv1+△Zv2) / 2.

[0020] Optionally, the slope Δk of adjacent points in step S5 is calculated by:

[0021] Set the adjacent points to (Zv5, Zf3), (Zv6, Zf4),

[0022] △k=(Zf3-Zf4) / (Zv5-Zv6).

[0023] Optionally, the discrete data processing in step S6 is performed in the following manner:

[0024] Select K adjacent data points and take the median as the smoothing value.

[0025] ,

[0026] ,

[0027] Where K is an odd number, W F For adjacent arrays, is the focus position after smoothing, G is the set W F The index or position number of any data point in , F is the current focus position that needs to be smoothed.

[0028] Optionally, the dimensions of the imaging data collected in step S1 include but are not limited to focal length, focus motor steps and defocus amount.

[0029] An optical imaging zoom point selection correction system adopts the optical imaging zoom point selection correction method, including a data acquisition module, a focus peak point tracking and error compensation module, and a curve calibration and smoothing optimization module;

[0030] Data acquisition module, used to collect theoretical data within the zoom range and construct a multi-dimensional data matrix;

[0031] Focus peak point tracking and error compensation module, used for peak point tracking algorithm and dynamic error compensation based on theoretical data;

[0032] The curve calibration and smoothing optimization module is used to generate a smooth and high-precision zoom focus curve through error parameters and discrete test points.

[0033] Optionally, the data acquisition module includes a sampling reference point unit, a primary sampling unit and an encrypted sampling unit;

[0034] Sampling reference point unit, used to set fixed reference points at the wide-angle end, mid-focus end, and telephoto end;

[0035] A primary sampling unit for collecting data across the entire zoom range with a fixed step size;

[0036] The encrypted sampling unit is used to perform encrypted sampling in the key areas of focal length connection and focus value inflection point.

[0037] Optionally, the focus peak point tracking and error compensation module includes a theoretical coordinate calculation unit, an adaptive step length search unit and an error compensation unit;

[0038] A theoretical coordinate calculation unit, used to calculate the coordinates of the theoretical focus peak point from the data matrix using a gradient descent method;

[0039] Adaptive step search unit, used to collect picture clarity data in real time through the initial step length and lock the actual peak point;

[0040] The error compensation unit is used to calculate the offset between the actual peak point and the theoretical peak point, and dynamically correct the theoretical model through the offset vector.

[0041] Beneficial effects of the present invention:

[0042] 1. In this invention, the deviation between the theoretical model and actual lens characteristics is corrected in real time through the peak point tracking algorithm and offset vector calculation in the second stage, effectively solving the problem of individual errors caused by lens assembly tolerances, material refractive index differences, etc. The layered sampling strategy (reference point + encrypted sampling) in the first stage is combined with the slope interpolation in the third stage to fill in the untested points in the theoretical curve, generating a high-precision focus curve that covers the entire zoom range and avoids the local focus failure caused by traditional uniform sampling.

[0043] 2. In this invention, the third stage introduces median filtering to filter outlier data, eliminate curve jitter caused by test noise or mechanical vibration, and output a smooth zoom focus curve. This improves the anti-interference ability in actual control and avoids frequent jitter of the focus motor. The second stage adopts an adaptive step size in the gradient ascent direction, dynamically adjusts the search strategy based on the clarity data, quickly locks on the actual peak point, and avoids the overshoot or slow convergence problems caused by the traditional fixed step size.

[0044] 3. In the present invention, the third stage reduces the number of calibration points to 1 / 5 of the total number of points, evenly distributes them, and supplements the remaining points through slope interpolation, which greatly reduces the test time. While ensuring accuracy, the calibration efficiency is improved by more than 80%. Through dynamic error compensation and actual peak point tracking, it adapts to the individual differences of different lenses without relying on a unified theoretical model. It is suitable for complex optical systems with high tolerance requirements, solves the pain point of inaccurate focusing of zoom network cameras in dynamic environments, and ensures high-definition imaging from wide-angle to telephoto. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 The present invention is a flow chart of a method.

[0046] Figure 2 This is a theoretical zoom focus diagram of the present invention.

[0047] Figure 3 This is an actual zoom focus diagram of the present invention.

[0048] Figure 4 This is a clarity data change diagram of the present invention.

[0049] Figure 5 This is a fitted curve graph containing outlier data of the present invention.

[0050] Figure 6This is a fitting curve diagram after median filtering of the present invention. DETAILED DESCRIPTION

[0051] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0052] like Figures 1 to 6 As shown, a method for optical imaging zoom point selection correction includes the following steps:

[0053] Step S1: Data acquisition, through primary sampling and reduced step sampling, imaging data sampling is performed on the optical zoom range with three-level sampling points set, and the acquired data is integrated into a multi-dimensional matrix;

[0054] Step S2: Calculating the theoretical focus peak point coordinates using multi-dimensional matrix data and gradient descent method, and the control system drives the zoom motor and focus group to move to the theoretical focus peak point coordinates;

[0055] Step S3: Adaptive step search, set the initial step size, move in the gradient ascending direction and collect picture clarity data, and when the clarity reaches the peak, lock the current coordinate as the actual zoom position;

[0056] Step S4: reverse optimization and error calculation, performing reverse search to determine the peak point of the defocus tolerance boundary, calculating the offset vector △Z between the actual peak point and the theoretical value, and realizing dynamic compensation of nonlinear error through the offset;

[0057] Step S5: Bring the offset ΔZ into the system, narrow the calibration points, obtain the focus peak points of L discrete focus points through the peak point tracking algorithm, and calculate the slopes of adjacent points to fill in the focus points of the missing test points in the theoretical curve;

[0058] Step S6: Use median filtering to process the discrete data in the fitting curve to generate a smooth zoom focus curve with the required accuracy, thereby achieving zoom point correction.

[0059] The specific implementation contents are as follows:

[0060] Phase 1: Theoretical data collection was carried out using stratified sampling method.

[0061] According to the manufacturer's specifications including curves, depth of focus parameters and zoom ratio, a three-level sampling strategy is set within the optical zoom range: first, reference points are set at the wide-angle end, mid-focus end and telephoto end, and then primary sampling is performed at n zoom steps. Key areas, such as the focal length connection and the focus value inflection point, are encrypted to half or even one-third of the original value. The collected data is used to construct a data matrix containing dimensions such as focal length, focus motor steps, and defocus amount.

[0062] Phase 2: In the focus optimization process of the device's optical system, a focus peak point tracking algorithm is used to implement precise focusing.

[0063] The technical architecture is based on the data matrix constructed in the first phase. This matrix not only includes core parameters such as the zoom motor step value and the focus group displacement, but also, by introducing the gradient descent method and the calculation model, the system will automatically solve the two-dimensional spatial coordinates corresponding to the theoretical optimal focus peak point, including the zoom ring position Zv and the focus group displacement Zf.

[0064] During the optical correction process of the device, the control system first drives the zoom motor and focus group to move to the theoretical coordinate point (such as Figure 2 ), at this time, the clarity data of the current picture is obtained through the system.

[0065] Then the system starts the adaptive step search mechanism: in the initial stage, it uses a precise step of 0.1mm to move in the predicted gradient rising direction. After each zoom displacement, the system automatically obtains the current picture clarity data. After obtaining the M field clarity data, when the data shows an upward and then downward trend (such as Figure 3 ); the system determines that it has reached the steady-state zoom peak area (such as Figure 3 ), the current mechanical coordinates will be automatically locked as the actual optimal zoom position.

[0066] After completing the peak positioning, the system will perform a reverse optimization process to determine the defocus tolerance boundary, and determine the optimal zoom peak point at the boundary position in the same way; thereby obtaining two landmark coordinates of the zoom process.

[0067] This stage achieves dynamic compensation of nonlinear errors by integrating deep data with the theoretical model of the first stage. Specifically, the system compares the actual measured two peak point coordinates (Zv3, Zf1), (Zv4, Zf2) with the theoretical values ​​of the corresponding focus positions (Zv1, Zf1), (Zv2, Zf2), and obtains two offsets △Zv1, △Zv2. The offset vector △Zv is calculated by averaging the offsets.

[0068] △Zv=(△Zv1+△Zv2) / 2.

[0069] Phase 3: Calibration of the optical zoom system.

[0070] First, the offset error parameter △Zv obtained from the second stage analysis is introduced into the system. Secondly, to reduce the curve calibration speed, the calibration points are reduced to 1 / 5 of the total number of points in the three segments, and points are evenly selected from the three segments. The system reads the L focus points placed in the third stage and obtains the focus peak point of each focus point through the focus peak point tracking algorithm. This results in L discrete two-dimensional arrays, which show a certain overlap with the first stage. At this time, the theoretical curve obtained in the first stage is used to calculate the slope △k of two adjacent focus points (Zv5, Zf3) and (Zv6, Zf4). This derives the focus points that complement the remaining untested points in the theoretical curve, resulting in an actual test zoom focus curve.

[0071] △k=(Zf3-Zf4) / (Zv5-Zv6)

[0072] After fitting the test points into a curve, the curve may not be smooth due to test errors and other reasons, which may affect the subsequent actual use effect (such as Figure 5 ).

[0073] In order to make the fitting data smoother, a median filter module is introduced after curve fitting to filter out individual outlier data and ensure that the fitting curve is smooth enough. F , select K arrays, K is an odd number, after smoothing for

[0074]

[0075] The adjacent array Defined as:

[0076] ,

[0077] Where K is an odd number, W F For adjacent arrays, is the focus position after smoothing, G is the set W F The index or position number of any data point in the image, F is the focus position that needs to be smoothed.

[0078] After filtering, a smooth and relatively accurate zoom focus curve can be obtained (such as Figure 6 ).

[0079] An optical imaging zoom point selection correction system adopts an optical imaging zoom point selection correction method, including a data acquisition module, a focus peak point tracking and error compensation module, and a curve calibration and smoothing optimization module;

[0080] Data acquisition module, used to collect theoretical data within the zoom range and construct a multi-dimensional data matrix;

[0081] Focus peak point tracking and error compensation module, used for peak point tracking algorithm and dynamic error compensation based on theoretical data;

[0082] The curve calibration and smoothing optimization module is used to generate a smooth and high-precision zoom focus curve through error parameters and discrete test points.

[0083] The data acquisition module includes a sampling reference point unit, a primary sampling unit and an encrypted sampling unit;

[0084] Sampling reference point unit, used to set fixed reference points at the wide-angle end, mid-focus end, and telephoto end;

[0085] A primary sampling unit for collecting data across the entire zoom range with a fixed step size;

[0086] The encrypted sampling unit is used to perform encrypted sampling in the key areas of focal length connection and focus value inflection point.

[0087] The focus peak point tracking and error compensation module includes a theoretical coordinate calculation unit, an adaptive step search unit and an error compensation unit;

[0088] A theoretical coordinate calculation unit, used to calculate the coordinates of the theoretical focus peak point from the data matrix using a gradient descent method;

[0089] Adaptive step search unit, used to collect picture clarity data in real time through the initial step length and lock the actual peak point;

[0090] The error compensation unit is used to calculate the offset between the actual peak point and the theoretical peak point, and dynamically correct the theoretical model through the offset vector.

[0091] The curve calibration and smoothing optimization module includes a discrete data acquisition unit, a slope interpolation calculation unit and a median filter smoothing unit;

[0092] A discrete data acquisition unit, used for acquiring discrete data on the fitting curve;

[0093] Slope interpolation calculation unit, used to supplement the focus position of untested points based on the slopes of adjacent points;

[0094] The median filter smoothing unit is used to perform median filtering on the discrete data in the fitting curve and output a smooth zoom focus curve.

[0095] This invention uses a peak point tracking algorithm and offset vector calculation in the second stage to correct the deviation between the theoretical model and actual lens characteristics in real time, effectively solving individual errors caused by lens assembly tolerances, material refractive index differences, and other factors. The first stage's layered sampling strategy (reference point + encrypted sampling) combined with the third stage's slope interpolation fills in untested points in the theoretical curve, generating a high-precision focus curve that covers the entire zoom range and avoids local focus failures caused by traditional uniform sampling.

[0096] The third stage introduces median filtering to filter outliers and eliminate curve jitter caused by test noise or mechanical vibration. This produces a smooth zoom focus curve, improving anti-interference capabilities in actual control and preventing frequent jitter in the focus motor. The second stage uses an adaptive step size in the gradient ascent direction, dynamically adjusting the search strategy based on clarity data to quickly locate the actual peak point and avoid overshoot or slow convergence caused by traditional fixed step sizes.

[0097] In the third stage, the number of calibration points is reduced to 1 / 5 of the total number of points, evenly distributed, and the remaining points are supplemented through slope interpolation, which greatly reduces testing time. While ensuring accuracy, the calibration efficiency is improved by more than 80%. Through dynamic error compensation and actual peak point tracking, it adapts to the individual differences of different lenses without relying on a unified theoretical model. It is suitable for complex optical systems with high tolerance requirements, solves the pain point of inaccurate focus of zoom network cameras in dynamic environments, and ensures high-definition imaging from wide-angle to telephoto.

[0098] In the engineering practice of complex optical imaging systems, the dynamic optical characteristics of each independent lens show significant individual differences due to the combined influence of multiple factors such as lens assembly tolerance, optical material refractive index deviation, and mechanical transmission mechanism matching clearance. To achieve continuous and stable imaging quality during zooming, the zoom tracking curve of each lens must be precisely calibrated and parameter optimized. Through three stages, the errors caused by multiple factors can be corrected to ensure stable imaging of the lens during zooming.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for correcting optical imaging zoom point selection, characterized in that: The following steps are involved: Step S1: Data acquisition, through primary sampling and reduced step sampling, imaging data sampling is performed on the optical zoom range with three-level sampling points set, and the acquired data is integrated into a multi-dimensional matrix; Step S2: Calculating the two-dimensional spatial coordinates of the theoretically optimal focus peak point using multi-dimensional matrix data and a gradient descent method, and controlling the system to drive the zoom motor and the focus group to move to the two-dimensional spatial coordinates of the optimal focus peak point; Step S3: Adaptive step search, setting the initial step, performing zoom displacement in the gradient ascending direction and collecting picture clarity data, and when the clarity reaches a peak, locking the current coordinates as the actual zoom position corresponding to the optimal focus peak point; Step S4: Reverse optimization and error calculation: Perform a reverse search to determine the defocus tolerance boundary. Use the same method as step S3 to determine the actual zoom position at the boundary. The two actual zoom position coordinates are obtained as the two landmark coordinates. The offset vector ΔZ between the actual zoom position of the two landmark coordinates and the theoretical value is calculated. Dynamic compensation of nonlinear errors is achieved through the offset. The offset vector △Z is calculated as follows: Compare the two actual zoom position coordinates (Zv3, Zf1), (Zv4, Zf2) measured with the theoretical values ​​of the corresponding zoom positions (Zv1, Zf1), (Zv2, Zf2) to obtain two offsets △Zv1, △Zv2. Calculate the offset vector △Zv by averaging the offsets. △Zv=(△Zv1+△Zv2) / 2; Step S5: Bring the offset ΔZ into the system, narrow the calibration points, obtain the focus peak points of L discrete focus points through the peak point tracking algorithm, and calculate the slopes of adjacent points to fill in the focus points of the missing test points in the theoretical curve; Step S6: Use median filtering to process the discrete data in the fitting curve to generate a smooth zoom focus curve with the required accuracy, thereby achieving zoom point correction.

2. The optical imaging zoom point selection correction method according to claim 1, characterized in that: The reference points of the three-level sampling points within the optical zoom range in step S1 are the wide-angle segment, the medium focal segment and the telephoto segment. The primary sampling collects data in a fixed step size, and the encrypted sampling collects data in a fixed step size that is equally divided.

3. The optical imaging zoom point selection correction method according to claim 1, characterized in that: The adaptive step length search in step S3 is performed in the following manner: Move in the direction of gradient ascent with an initial step size, collecting picture clarity data after each movement. When the clarity data shows an upward and then downward trend, in order to reach the peak area, lock the current coordinate as the actual zoom position.

4. The optical imaging zoom point selection correction method according to claim 1, characterized in that: The slope Δk of adjacent points in step S5 is calculated as follows: Set the adjacent points to (Zv5, Zf3), (Zv6, Zf4), △k=(Zf3-Zf4) / (Zv5-Zv6).

5. The optical imaging zoom point selection correction method according to claim 1, characterized in that: The dimensions of the imaging data collected in step S1 include but are not limited to focal length, focus motor steps and defocus amount.

6. An optical imaging zoom point selection correction system, using the optical imaging zoom point selection correction method according to any one of claims 1 to 5, characterized in that: It includes data acquisition module, focus peak point tracking and error compensation module and curve calibration and smoothing optimization module; Data acquisition module, used to collect theoretical data within the zoom range and construct a multi-dimensional data matrix; Focus peak point tracking and error compensation module, which is used to dynamically correct the theoretical model based on theoretical data by calculating the offset through the peak point tracking algorithm and dynamic error compensation; The curve calibration and smoothing optimization module is used to generate a smooth and high-precision zoom focus curve through error parameters and discrete test points.

7. The optical imaging zoom point selection correction system according to claim 6, characterized in that: The data acquisition module includes a sampling reference point unit, a primary sampling unit and an encrypted sampling unit; Sampling reference point unit, used to set fixed reference points at wide-angle, medium and telephoto segments; A primary sampling unit for collecting data across the entire zoom range with a fixed step size; The encrypted sampling unit is used to perform encrypted sampling in the key areas of focal length connection and focus value inflection point.

8. The optical imaging zoom point selection correction system according to claim 6, characterized in that: The focus peak point tracking and error compensation module includes a theoretical coordinate calculation unit, an adaptive step length search unit and an error compensation unit; A theoretical coordinate calculation unit, used to calculate the coordinates of the theoretical focus peak point from the data matrix using a gradient descent method; Adaptive step search unit, used to collect picture clarity data in real time through the initial step length and lock the actual peak point; The error compensation unit is used to calculate the offset between the actual peak point and the theoretical peak point, and dynamically correct the theoretical model through the offset vector.

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