An optical lens aperture intelligent adjusting method

Abstract

The present application relates to the field of optical imaging technology, and more particularly to an optical lens aperture intelligent adjustment method, comprising: acquiring a current frame image of an imaging device and a current exposure parameter, performing target identification on the current frame image, and determining target state information; determining an illumination state according to the brightness relationship between the target region and the background region and the full-frame brightness level; determining aperture adjustment constraints, determining an aperture target gear based on lens optical calibration data; determining the adjustment amount of the exposure time and the gain; driving the lens aperture to the aperture target gear and confirming the position through position feedback; when there is a target, performing imaging quality evaluation on the target region, determining the recognizable degree and the quality deviation type; when the recognizable degree does not meet the expectation, adjusting the aperture according to the quality deviation type and the deviation degree and re-identifying the target in the current frame image. The present application improves the stability of aperture intelligent adjustment.

Description

Technical Field

[0001] This invention relates to the field of optical imaging technology, and in particular to a method for intelligent adjustment of the aperture of an optical lens. Background Technology

[0002] With the widespread application of imaging equipment in industrial inspection and everyday photography, situations where the background brightness is significantly higher than the target or the target itself is overly bright have become a key issue affecting image quality. In industrial settings, when industrial cameras monitor molten material processing or large metal casting, the target itself is often overly bright. In everyday photography, backlighting, night scenes, and water reflections such as seascapes and waterscapes all present situations where the background brightness is significantly higher than the target or the target itself is overly bright. When the target itself is overly bright, average metering across the entire frame results in either underexposure or blown-out highlights, making the target unrecognizable. When the background brightness is high and the ambient light is low, the shutter speed and gain reach their adjustment limits, forcing the aperture to open wide, resulting in a drastically shallow depth of field. Distant targets may be out of focus, exceeding the depth of field coverage, thus affecting the shooting results. Existing imaging devices typically employ automatic aperture control, with mainstream solutions including: brightness closed-loop, which measures the average brightness of the entire image, compares it with the target brightness, and then drives the aperture until the image brightness reaches the target; precise aperture, which fixes the aperture at the high-performance position calibrated by the lens at the factory, with changes in illumination compensated by gain and exposure time, and only adjusting the aperture when electronic compensation is insufficient; and solutions that map the aperture stop according to zoom ratio or significant depth of the subject. All of these solutions control the overall image brightness or a single dimension as the control objective, failing to consider the target's own image quality as the ultimate goal of aperture adjustment. In scenes where the target is highly luminous or the background brightness is significantly higher than the target, the discernibility of the target area cannot be guaranteed. Therefore, there is an urgent need for an intelligent aperture adjustment method that takes the image quality of the target object as the ultimate control objective.

[0003] Chinese Patent Publication No. CN105338235A discloses an automatic aperture adjustment method and apparatus. The method includes: determining a first brightness adjustment amount based on the difference between the average brightness of the image captured by the automatic aperture lens and the target brightness; adjusting the aperture of the automatic aperture lens based on the first brightness adjustment amount; and / or adjusting the exposure time and gain of the image sensor. It is evident that the automatic aperture adjustment method and apparatus suffer from the problem that, because it uses the average brightness of the entire image as the sole control target and adjusts the aperture aperture through a closed-loop brightness difference, in scenes where the target itself is highly bright or the background brightness is much higher than the target, metering based on the average brightness of the entire image will result in underexposure or highlight blowout in the target area, leading to a failure to guarantee the discernibility of the target area. Summary of the Invention

[0004] To address this, the present invention provides an intelligent aperture adjustment method for optical lenses, which overcomes the problems in the prior art where the aperture is controlled by the brightness of the entire screen or a single dimension, resulting in underexposure or highlight overflow of the target area, out-of-focus targets at a distance, and inability to guarantee the recognizability of the target in scenes where the target itself is brighter or the background brightness is much higher than the target.

[0005] To achieve the above objectives, the present invention provides an intelligent aperture adjustment method for an optical lens, comprising: The current frame image and current exposure parameters of the imaging device are acquired, and target recognition is performed on the current frame image to determine the target status information. The current exposure parameters include the current aperture setting, the current exposure time, and the current gain; the target status information includes the target area, the target image velocity, and the target distance range. The lighting status is determined based on the brightness relationship between the target area and the background area, as well as the overall brightness level of the screen. The lighting conditions include backlighting, strong light, weak light, and normal conditions. Based on the target state information and the illumination state, aperture adjustment constraints are determined. If the current exposure parameters cannot meet at least one of the constraints, the adjustment direction is determined based on the unmet constraints, and the target aperture level is determined based on the lens optical calibration data. Among them, aperture adjustment constraints include the direction of light intake adjustment, motion imaging constraints, and depth of field constraints; The adjustment amount of exposure time and gain is determined based on the change in the amount of light entering the target aperture relative to the current aperture. Drive the lens aperture to the target aperture setting and confirm its position via position feedback; When a target is present, the imaging quality of the target area is assessed to determine its recognizability and the type of quality deviation. When the recognizability does not meet expectations, the aperture setting is adjusted back according to the type and degree of quality deviation, and the target recognition of the current frame image is re-performed.

[0006] Further, target recognition is performed on the current frame image to determine target state information, including: Target detection is performed on the current frame image to obtain the target region; The target image plane velocity is determined based on the regional displacement of the same target in adjacent frame images; The target distance range is determined based on the imaging size of the target region in the current frame image and the lens focal length.

[0007] Furthermore, based on the brightness relationship between the target area and the background area, as well as the overall brightness level of the screen, the lighting condition is determined, including: When the average brightness of the target area is less than the average brightness of the background area, and the difference between the average brightness of the target area and the background area is greater than the dispersion of the brightness distribution of the background area, it is determined to be a backlight state. When the target area has a continuous saturated pixel area, and the continuous saturated pixel area continues to expand or persist in adjacent frames, it is determined to be a strong light state. When the overall brightness of the image does not change accordingly with the increase in exposure time or gain, it is judged as a low light state. When none of the conditions of backlight, strong light, and weak light are met, the condition is determined to be normal.

[0008] Furthermore, when the illumination state is a backlight state or a strong light state, the direction of adjusting the amount of light entering is to reduce the amount of light entering; When the illumination state is a weak light state, the direction of light intake adjustment is to increase the light intake; When the illumination state is normal, the direction of light intake adjustment is to maintain the current light intake. When the exposure time reaches the frame period limit and the gain reaches the limit, the direction of increasing the amount of light is undertaken by the aperture, and the aperture is opened to supplement the amount of light.

[0009] Furthermore, the motion imaging constraint is that the product of the target image plane velocity and the current exposure time does not exceed the freeze limit; When the product exceeds the freezeable amount, the current exposure time is compressed to a duration where the product does not exceed the freezeable amount, and the aperture is adjusted according to the light difference. The remaining brightness difference is compensated by gain.

[0010] Furthermore, the depth-of-field constraint is that the target distance range is within the depth-of-field coverage range of the current aperture setting, and the correspondence between the depth-of-field coverage range and the aperture setting is provided by the lens optical calibration data; When the target distance range exceeds the depth of field coverage range, the aperture is reduced until the depth of field coverage range covers the target distance range or the aperture reaches the boundary setting of the optical calibration curve.

[0011] Furthermore, when at least one of the light intake adjustment direction, the motion imaging constraint, and the depth of field constraint is not satisfied, the adjustment direction of the lens aperture is determined in the order of the light intake adjustment direction, the motion imaging constraint, and the depth of field constraint.

[0012] Furthermore, the target aperture stop is determined based on the lens optical calibration data, including: Determine the lens optical calibration curve based on the lens optical calibration data; The candidate aperture settings are verified according to the lens optical calibration curve. When a candidate aperture setting falls into the degradation zone of the lens optical calibration curve, the boundary setting of the degradation zone is selected as the target aperture setting. Based on the change in the amount of light entering the target aperture relative to the current aperture, the adjustment amount of exposure time and gain is determined.

[0013] Further, determining the identifiability and quality deviation type of the target region includes: Target detection is performed on the target area, and the average brightness of the target area is calculated; When the target detection detects the target, it is determined that the target region is identifiable; When the target detection fails to detect the target, the target area is determined to be unidentifiable, and the quality deviation type is determined: When the average brightness of the target area is less than the average brightness of the background area or when the target area contains a continuous saturated pixel area, the quality deviation type is exposure deviation. When the velocity of the target image plane exceeds the freeze limit, the quality deviation type is motion blur deviation; When the target distance range exceeds the depth of field coverage range, the quality deviation type is depth of field coverage deviation.

[0014] Furthermore, adjusting the aperture based on the type and degree of the quality deviation includes: When the quality deviation type is exposure deviation, if there is a continuous saturated pixel area in the target area, the aperture is reduced until the continuous saturated pixel area disappears; If the average brightness of the target area is less than the average brightness of the background area, the aperture is reduced based on the target area, and the brightness difference of the target area is compensated by the exposure time and gain. When the quality deviation type is motion blur deviation, compress the exposure time and adjust the aperture and gain accordingly. When the quality deviation type is depth of field coverage deviation, stop down the aperture until the depth of field coverage range covers the target distance range or the aperture reaches the boundary setting of the optical calibration curve; When the relationship between the average brightness of the target area and the average brightness of the background area changes in the opposite direction after the callback, the aperture is narrowed to the middle setting and frozen until the lighting state or target state information changes.

[0015] Compared with existing technologies, the beneficial effects of this invention are as follows: The method of this invention uses adaptive aperture control based on the difference between the target and the background in the imaging scene, avoiding the problem of traditional aperture adjustment relying solely on the overall exposure state, resulting in suitable exposure of the target area but poor actual imaging effect. This improves the adaptability of aperture adjustment to complex lighting environments and different target states. By establishing a synergistic relationship between aperture changes and other exposure parameters of the imaging system, the impact of changes in the amount of light entering the image on the stability of image exposure can be reduced during aperture adjustment, minimizing repeated adjustments, sudden exposure changes, and image brightness fluctuations, thus improving the continuity and stability of the imaging process. Simultaneously, by improving the actual imaging effect of the target area… Further verification will enable the aperture adjustment results to be based on the actual recognizability of the target, avoiding judgment of the adjustment results solely based on the theoretical exposure state. This allows the system to promptly detect problems such as insufficient target detail and local imaging anomalies and make targeted corrections, thereby improving the detail preservation capability and recognition reliability of the target area. In addition, by providing feedback correction to the aperture adjustment results, the aperture control can be transformed from a single, open-loop adjustment to a closed-loop optimization process oriented towards the target imaging results. This allows for continuous correction of the adjustment results when different target states and environmental conditions change, reducing the dependence of fixed adjustment strategies on equipment parameters and usage scenarios, and improving the stability of intelligent aperture adjustment.

[0016] Furthermore, the method described in this invention, by acquiring the target area, target image velocity, and target distance range, can form more complete target state information from aspects such as the target's spatial position and motion state, providing a targeted control basis for subsequent aperture adjustment. Simultaneously, by combining the brightness relationship between the target area and the background area, the background brightness distribution, and the cross-frame changes in continuous saturation areas, it distinguishes between backlight, strong light, weak light, and normal lighting states, reducing misjudgments caused by relying solely on the overall image brightness and improving the accuracy of lighting state recognition in complex lighting environments. Furthermore, using the target state and lighting state for subsequent aperture control allows the aperture adjustment to adapt to different target distances, motion states, and lighting conditions, reducing unnecessary repeated aperture adjustments and exposure fluctuations, further improving the stability of intelligent aperture adjustment.

[0017] Furthermore, the method of this invention directly determines the direction of light intake adjustment based on the illumination state, and when both the exposure time and gain reach their upper limits, the aperture takes over increasing the light intake. Since the correspondence between the light intake direction and the illumination state is clear, and the aperture only adjusts the light intake when exposure resources are exhausted, it achieves unambiguous determination of the aperture adjustment direction under backlight, strong light, and weak light conditions, and ensures the brightness of the target area under weak light conditions. The product of the target image plane velocity and the current exposure time is used as a motion imaging constraint, and when the light intake is excessive, the exposure time is compressed, and the aperture and gain compensate for the difference in light intake. Due to motion... The computational chain of imaging constraints is closed, achieving motionless imaging of moving targets. The inclusion relationship between the target distance range and the depth of field coverage range is used as the depth of field constraint, and the correspondence between the depth of field coverage range and the aperture stop is provided by the lens optical calibration data. Since the inherent optical relationship between the aperture and the depth of field coverage range is calibrated and fixed, clear imaging of targets at different distances is achieved. The method described in this invention determines the aperture adjustment direction sequentially when multiple constraints are not satisfied. Since the processing order of each constraint is clear, conflicts in the aperture adjustment direction when multiple constraints compete are avoided, further improving the stability of intelligent aperture adjustment.

[0018] Furthermore, the method of the present invention verifies candidate aperture settings using optical calibration curves and calculates the adjustment amount of exposure time and gain in a linkage with exposure conservation. Since the aperture adjustment is constrained by the inherent optical characteristics of the lens throughout the process and brightness changes are compensated in a linkage manner, the aperture is prevented from falling into the diffraction or aberration degradation region, while preventing brightness jumps caused by aperture adjustment. The discriminability is determined by the detection of events by target detection, and the source of deviation is diagnosed by reusing observable conditions. Since the evaluation benchmark is the target identification result and the source of deviation can be located, the task-level verification of the aperture adjustment effect is realized. The aperture is adjusted according to the target guidance of the quality deviation type until the conditions are met and convergence and freezing occur during oscillation. Since the adjustment amount is naturally determined by the degree of deviation and no fixed step size is required, the rapid convergence and stability of aperture adjustment are realized, further improving the stability of intelligent aperture adjustment. Attached Figure Description

[0019] Figure 1 This is an overall flowchart of the intelligent aperture adjustment method for optical lenses according to an embodiment of the present invention; Figure 2 This is a flowchart illustrating the illumination state determination process of the intelligent aperture adjustment method for optical lenses according to an embodiment of the present invention. Figure 3 This is a flowchart illustrating the process of determining the aperture adjustment constraint and target setting in the intelligent aperture adjustment method for optical lenses according to an embodiment of the present invention. Figure 4 This is a flowchart illustrating the feedback callback process of the intelligent aperture adjustment method for optical lenses according to an embodiment of the present invention. Detailed Implementation

[0020] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0021] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0022] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0023] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] Please see Figure 1 The diagram shown is an overall flowchart of the intelligent aperture adjustment method for optical lenses according to an embodiment of the present invention. The method described in this embodiment includes: Step S1: Acquire the current frame image and current exposure parameters of the imaging device, and perform target recognition on the current frame image to determine the target state information, wherein... The current exposure parameters include the current aperture setting, the current exposure time, and the current gain; the target status information includes the target area, the target image velocity, and the target distance range. Step S2: Determine the lighting status based on the brightness relationship between the target area and the background area and the overall brightness level of the screen; The lighting conditions include backlighting, strong light, weak light, and normal conditions. Step S3: Determine aperture adjustment constraints based on the target state information and the illumination state. When the current exposure parameters cannot meet at least one of the constraints, determine the adjustment direction based on the unmet constraints, and determine the target aperture level based on the lens optical calibration data. Among them, aperture adjustment constraints include the direction of light intake adjustment, motion imaging constraints, and depth of field constraints; Step S4: Determine the adjustment amount of exposure time and gain based on the change in the amount of light entering the target aperture relative to the current aperture. Step S5: Drive the lens aperture to the target aperture setting and confirm its position via position feedback; Step S6: When a target is present, perform an imaging quality assessment on the target area to determine the identifiability and the type of quality deviation. Step S7: When the recognizability does not meet expectations, the aperture is reverted according to the quality deviation type and degree, and the target recognition of the current frame image is re-performed.

[0025] In this embodiment, the method uses adaptive aperture control based on the difference between the target and the background in the imaging scene. This avoids the problem of traditional aperture adjustment relying solely on the overall exposure state, resulting in suitable exposure of the target area but poor actual imaging effect. This improves the adaptability of aperture adjustment to complex lighting environments and different target states. By establishing a synergistic relationship between aperture changes and other exposure parameters of the imaging system, the method reduces the impact of changes in light intake on image exposure stability during aperture adjustment, minimizing repeated adjustments, sudden exposure changes, and image brightness fluctuations, thus improving the continuity and stability of the imaging process. Furthermore, the method further verifies the actual imaging effect on the target area. This allows the aperture adjustment results to be based on the actual recognizability of the target, avoiding judgment based solely on theoretical exposure conditions. This enables the system to promptly detect issues such as insufficient target detail and local imaging anomalies, and to make targeted corrections, thereby improving the detail retention and recognition reliability of the target area. Furthermore, by providing feedback correction to the aperture adjustment results, aperture control can be transformed from a single, open-loop adjustment into a closed-loop optimization process oriented towards the target imaging results. This allows for continuous correction of the adjustment results as different target states and environmental conditions change, reducing the dependence of fixed adjustment strategies on equipment parameters and usage scenarios, and improving the stability of intelligent aperture adjustment.

[0026] Please see Figure 2 As shown, it is a logical flowchart of the illumination state determination process in an embodiment of the present invention.

[0027] Specifically, performing target recognition on the current frame image to determine target state information includes: Target detection is performed on the current frame image to obtain the target region; The target image plane velocity is determined based on the regional displacement of the same target in adjacent frame images; The target distance range is determined based on the imaging size of the target region in the current frame image and the lens focal length.

[0028] Specifically, the lighting state is determined based on the brightness relationship between the target area and the background area, as well as the overall brightness level of the screen, including: When the average brightness of the target area is less than the average brightness of the background area, and the difference between the average brightness of the target area and the background area is greater than the dispersion of the brightness distribution of the background area, it is determined to be a backlight state. When the target area has a continuous saturated pixel area, and the continuous saturated pixel area continues to expand or persist in adjacent frames, it is determined to be a strong light state. When the overall brightness of the image does not change accordingly with the increase in exposure time or gain, it is judged as a low light state. When none of the conditions of backlight, strong light, and weak light are met, the condition is determined to be normal.

[0029] Specifically, the calculation process for the average brightness of the target area involves extracting the brightness value corresponding to each pixel within the target area, and averaging the obtained brightness values ​​of each pixel within the target area to obtain the average brightness of the target area.

[0030] Specifically, the process of calculating the average brightness of the background area involves extracting the brightness value corresponding to each pixel within the background area, and then averaging the brightness values ​​of the pixels within the background area to obtain the average brightness of the background area.

[0031] Specifically, the average brightness difference between the target area and the background area is the difference between the average brightness of the target area and the average brightness of the background area.

[0032] Specifically, the dispersion of the brightness distribution in the background region is the range of fluctuation of the brightness of each pixel in the background region relative to its average brightness, and the standard deviation of the brightness distribution in the background region.

[0033] It is understandable that when the average brightness difference between the target area and the background area is greater than this fluctuation range, it means that the brightness difference between the two exceeds the fluctuation of the background itself, which is a real brightness separation rather than noise fluctuation, and is judged as a backlight state. A continuous saturated pixel region is a set of pixels whose pixel values ​​reach the sensor saturation level and are spatially continuous. The sensor saturation level is an inherent electrical property of the image sensor. When a continuous saturated pixel region exists continuously or its area expands in adjacent frames, it indicates that the bright area exists stably or intensifies, rather than a single-frame transient interference, and is determined to be a strong light state. When the exposure time has reached the frame period limit or the gain has reached the limit, if the exposure time or gain is increased further, the brightness of the entire screen will no longer change accordingly with the increase in exposure, and the screen will be judged as a low light state.

[0034] In this embodiment, the method acquires the target area, target image velocity, and target distance range, enabling the formation of more complete target state information from aspects such as the target's spatial position and motion state, providing a targeted control basis for subsequent aperture adjustment. Simultaneously, by combining the brightness relationship between the target area and the background area, the background brightness distribution, and the cross-frame changes in continuous saturation areas, it distinguishes between backlight, strong light, weak light, and normal lighting states, reducing misjudgments caused by relying solely on overall image brightness and improving the accuracy of lighting state recognition in complex lighting environments. Furthermore, using the target state and lighting state for subsequent aperture control allows aperture adjustment to adapt to different target distances, motion states, and lighting conditions, reducing unnecessary repeated aperture adjustments and exposure fluctuations, further improving the stability of intelligent aperture adjustment.

[0035] Please see Figure 3 As shown, it is a logic flowchart of the aperture adjustment constraint and target gear determination process in an embodiment of the present invention.

[0036] Specifically, when the illumination state is a backlight state or a strong light state, the direction of adjusting the amount of light entering is to reduce the amount of light entering; When the illumination state is a weak light state, the direction of light intake adjustment is to increase the light intake; When the illumination state is normal, the direction of light intake adjustment is to maintain the current light intake. When the exposure time reaches the frame period limit and the gain reaches the limit, the direction of increasing the amount of light is undertaken by the aperture, and the aperture is opened to supplement the amount of light.

[0037] Specifically, the motion imaging constraint is that the product of the target image plane velocity and the current exposure time does not exceed the freeze limit. When the product exceeds the freezeable amount, the current exposure time is compressed to a duration where the product does not exceed the freezeable amount, and the aperture is adjusted according to the light difference. The remaining brightness difference is compensated by gain.

[0038] Specifically, the depth-of-field constraint is that the target distance range is within the depth-of-field coverage range of the current aperture setting, and the correspondence between the depth-of-field coverage range and the aperture setting is provided by the lens optical calibration data; When the target distance range exceeds the depth of field coverage range, the aperture is reduced until the depth of field coverage range covers the target distance range or the aperture reaches the boundary setting of the optical calibration curve.

[0039] Specifically, when at least one of the light intake adjustment direction, the motion imaging constraint, and the depth of field constraint is not satisfied, the adjustment direction of the lens aperture is determined in the order of the light intake adjustment direction, the motion imaging constraint, and the depth of field constraint.

[0040] Specifically, determining the target aperture stop based on lens optical calibration data includes: Determine the lens optical calibration curve based on the lens optical calibration data; The candidate aperture settings are verified according to the lens optical calibration curve. When a candidate aperture setting falls into the degradation zone of the lens optical calibration curve, the boundary setting of the degradation zone is selected as the target aperture setting. Based on the change in the amount of light entering the target aperture relative to the current aperture, the adjustment amount of exposure time and gain is determined.

[0041] Specifically, the process of determining the target aperture level based on lens optical calibration data is as follows: each candidate level is verified according to the lens optical calibration curve. When a candidate level falls into the degradation zone of the optical calibration curve, the boundary level of the degradation zone is selected as the target aperture level. Based on the principle of exposure conservation, the adjustment amount of exposure time and gain is determined according to the change in the amount of light entering the target aperture level relative to the current aperture level.

[0042] Specifically, the degradation zone of the lens optical calibration curve is determined by the lens optical calibration data. Specifically, the degradation zone of the lens optical calibration curve corresponds to the aperture range after the aperture is adjusted in the shrinking direction, where the depth of field coverage continues to change but the direction of change violates the aperture stop range required for imaging the target area.

[0043] It is understood that in this embodiment, the determination of the target aperture setting is constrained by the lens optical calibration curve. If the candidate setting falls into the small aperture diffraction region or the large aperture aberration region, the boundary setting of the degradation region is taken. The brightness difference is compensated by the exposure time and gain, so that the aperture is always in the imaging setting range between aberration and diffraction.

[0044] In this embodiment, the method directly determines the direction of light intake adjustment based on the illumination state. When both exposure time and gain reach their upper limits, the aperture takes over increasing the amount of light intake. Since the correspondence between the direction of light intake and the illumination state is clear, and the aperture only adjusts the light intake when exposure resources are exhausted, it achieves unambiguous determination of the aperture adjustment direction under backlight, strong light, and weak light conditions, and ensures the brightness of the target area in weak light conditions. The product of the target image plane velocity and the current exposure time is used as a motion imaging constraint. When the light intake is excessive, the exposure time is compressed, and the aperture and gain compensate for the difference in light intake. Because of the motion... The computational chain of constraints is closed to achieve motionless imaging of moving targets. The inclusion relationship between the target distance range and the depth of field coverage range is used as the depth of field constraint, and the correspondence between the depth of field coverage range and the aperture stop is provided by the lens optical calibration data. Since the inherent optical relationship between the aperture and the depth of field coverage range is calibrated and fixed, clear imaging of targets at different distances is achieved. The method described in this invention determines the aperture adjustment direction sequentially when multiple constraints are not satisfied. Since the processing order of each constraint is clear, conflicts in the aperture adjustment direction when multiple constraints compete are avoided, further improving the stability of intelligent aperture adjustment.

[0045] Please see Figure 4 As shown, it is a logical flowchart of the feedback callback process in an embodiment of the present invention.

[0046] Specifically, determining the identifiability and quality deviation type of the target region includes: Target detection is performed on the target area, and the average brightness of the target area is calculated; When the target detection detects the target, it is determined that the target region is identifiable; When the target detection fails to detect the target, the target area is determined to be unidentifiable, and the quality deviation type is determined: When the average brightness of the target area is less than the average brightness of the background area or when the target area contains a continuous saturated pixel area, the quality deviation type is exposure deviation. When the velocity of the target image plane exceeds the freeze limit, the quality deviation type is motion blur deviation; When the target distance range exceeds the depth-of-field coverage range, the quality deviation type is depth-of-field coverage.

[0047] Specifically, adjusting the aperture based on the type and degree of quality deviation includes: When the quality deviation type is exposure deviation, if there is a continuous saturated pixel area in the target area, the aperture is reduced until the continuous saturated pixel area disappears; If the average brightness of the target area is less than the average brightness of the background area, the aperture is reduced based on the target area, and the brightness difference of the target area is compensated by the exposure time and gain. When the quality deviation type is motion blur deviation, compress the exposure time and adjust the aperture and gain accordingly. When the quality deviation type is depth of field coverage deviation, stop down the aperture until the depth of field coverage range covers the target distance range or the aperture reaches the boundary setting of the optical calibration curve; When the relationship between the average brightness of the target area and the average brightness of the background area changes in the opposite direction after the callback, the aperture is narrowed to the middle setting and frozen until the lighting state or target state information changes.

[0048] Specifically, the freeze limit is the maximum image plane displacement allowed for the target area during a single exposure.

[0049] Understandably, narrowing the aperture until the continuous saturated pixel area disappears is a target-oriented adjustment that continues until the condition is met. The adjustment amount is determined by the degree of deviation and there is no need to set a fixed step size. After the pullback, the relationship between the average brightness of the target area and the average brightness of the background area changes in reverse, indicating that the aperture has passed the optimal setting. At this time, the aperture is narrowed to the middle setting and frozen to prevent the aperture from switching back and forth between adjacent settings.

[0050] In this embodiment, the method verifies candidate aperture settings using optical calibration curves and calculates the adjustment amount of exposure time and gain using exposure conservation linkage. Since the aperture adjustment is constrained by the inherent optical characteristics of the lens throughout the process and brightness changes are compensated in linkage, the aperture is prevented from falling into the diffraction or aberration degradation region. At the same time, it prevents the aperture adjustment from causing brightness jumps. The identifiability is determined by the target detection event, and the observable conditions are reused to diagnose the source of deviation. Since the evaluation benchmark is the target identification result and the source of deviation can be located, the task-level verification of the aperture adjustment effect is realized. The aperture is adjusted according to the target guidance of the quality deviation type until the conditions are met and convergence and freezing occur during oscillation. Since the adjustment amount is naturally determined by the degree of deviation and no fixed step size is required, the aperture adjustment is rapidly converged and stabilized, further improving the stability of intelligent aperture adjustment.

[0051] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for intelligent aperture adjustment of an optical lens, characterized in that, include: The current frame image and current exposure parameters of the imaging device are acquired, and target recognition is performed on the current frame image to determine the target status information. The current exposure parameters include the current aperture setting, the current exposure time, and the current gain; the target status information includes the target area, the target image velocity, and the target distance range. The lighting status is determined based on the brightness relationship between the target area and the background area, as well as the overall brightness level of the screen. The lighting conditions include backlighting, strong light, weak light, and normal conditions. Based on the target state information and the illumination state, aperture adjustment constraints are determined. If the current exposure parameters cannot meet at least one of the constraints, the adjustment direction is determined based on the unmet constraints, and the target aperture level is determined based on the lens optical calibration data. Among them, aperture adjustment constraints include the direction of light intake adjustment, motion imaging constraints, and depth of field constraints; The adjustment amount of exposure time and gain is determined based on the change in the amount of light entering the target aperture relative to the current aperture. Drive the lens aperture to the target aperture setting and confirm its position via position feedback; When a target is present, the imaging quality of the target area is assessed to determine its recognizability and the type of quality deviation. When the recognizability does not meet expectations, the aperture setting is adjusted back according to the type and degree of quality deviation, and the target recognition of the current frame image is re-performed.

2. The intelligent aperture adjustment method for optical lenses according to claim 1, characterized in that, Perform target recognition on the current frame image to determine target state information, including: Target detection is performed on the current frame image to obtain the target region; The target image plane velocity is determined based on the regional displacement of the same target in adjacent frame images; The target distance range is determined based on the imaging size of the target region in the current frame image and the lens focal length.

3. The intelligent aperture adjustment method for optical lenses according to claim 2, characterized in that, Based on the brightness relationship between the target area and the background area, and the overall brightness level of the screen, the lighting condition is determined, including: When the average brightness of the target area is less than the average brightness of the background area, and the difference between the average brightness of the target area and the background area is greater than the dispersion of the brightness distribution of the background area, it is determined to be a backlight state. When the target area has a continuous saturated pixel area, and the continuous saturated pixel area continues to expand or persist in adjacent frames, it is determined to be a strong light state. When the overall brightness of the image does not change accordingly with the increase in exposure time or gain, it is judged as a low light state. When none of the conditions of backlight, strong light, and weak light are met, the condition is determined to be normal.

4. The intelligent aperture adjustment method for optical lenses according to claim 3, characterized in that, When the illumination state is backlighting or strong light, the direction of light intake adjustment is to reduce the amount of light entering the body; When the illumination state is a weak light state, the direction of light intake adjustment is to increase the light intake; When the illumination state is normal, the direction of light intake adjustment is to maintain the current light intake. When the exposure time reaches the frame period limit and the gain reaches the limit, the direction of increasing the amount of light is undertaken by the aperture, and the aperture is opened to supplement the amount of light.

5. The intelligent aperture adjustment method for optical lenses according to claim 4, characterized in that, The motion imaging constraint is that the product of the target image plane velocity and the current exposure time does not exceed the freeze limit. When the product exceeds the freezeable amount, the current exposure time is compressed to a duration where the product does not exceed the freezeable amount, and the aperture is adjusted according to the light difference. The remaining brightness difference is compensated by gain.

6. The intelligent aperture adjustment method for optical lenses according to claim 5, characterized in that, The depth-of-field constraint is that the target distance range is within the depth-of-field coverage range of the current aperture setting, and the correspondence between the depth-of-field coverage range and the aperture setting is provided by the lens optical calibration data; When the target distance range exceeds the depth of field coverage range, the aperture is reduced until the depth of field coverage range covers the target distance range or the aperture reaches the boundary setting of the optical calibration curve.

7. The intelligent aperture adjustment method for optical lenses according to claim 6, characterized in that, When at least one of the light intake adjustment direction, the motion imaging constraint, and the depth of field constraint is not satisfied, the adjustment direction of the lens aperture is determined in the order of the light intake adjustment direction, the motion imaging constraint, and the depth of field constraint.

8. The intelligent aperture adjustment method for an optical lens according to claim 7, characterized in that, Determining the target aperture stop based on lens optical calibration data includes: Determine the lens optical calibration curve based on the lens optical calibration data; The candidate aperture settings are verified according to the lens optical calibration curve. When a candidate aperture setting falls into the degradation zone of the lens optical calibration curve, the boundary setting of the degradation zone is selected as the target aperture setting. Based on the change in the amount of light entering the target aperture relative to the current aperture, the adjustment amount of exposure time and gain is determined.

9. The intelligent aperture adjustment method for an optical lens according to claim 8, characterized in that, Determining the identifiability and quality deviation type of the target region includes: Target detection is performed on the target area, and the average brightness of the target area is calculated; When the target detection detects the target, it is determined that the target region is identifiable; When the target detection fails to detect the target, the target area is determined to be unidentifiable, and the quality deviation type is determined: When the average brightness of the target area is less than the average brightness of the background area or when the target area contains a continuous saturated pixel area, the quality deviation type is exposure deviation. When the velocity of the target image plane exceeds the freeze limit, the quality deviation type is motion blur deviation; When the target distance range exceeds the depth of field coverage range, the quality deviation type is depth of field coverage deviation.

10. The intelligent aperture adjustment method for an optical lens according to claim 9, characterized in that, Adjusting the aperture based on the type and degree of quality deviation includes: When the quality deviation type is exposure deviation, if there is a continuous saturated pixel area in the target area, the aperture is reduced until the continuous saturated pixel area disappears; If the average brightness of the target area is less than the average brightness of the background area, the aperture is reduced based on the target area, and the brightness difference of the target area is compensated by the exposure time and gain. When the quality deviation type is motion blur deviation, compress the exposure time and adjust the aperture and gain accordingly. When the quality deviation type is depth of field coverage deviation, stop down the aperture until the depth of field coverage range covers the target distance range or the aperture reaches the boundary setting of the optical calibration curve; When the relationship between the average brightness of the target area and the average brightness of the background area changes in the opposite direction after the callback, the aperture setting is converged to the middle setting and frozen until the lighting state or target state information changes.

Images