Video Camera Automatic Exposure Aperture Control
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Solution Overview
Problem
Current automatic exposure algorithms in video cameras fail to ensure optimal shutter and depth of field, leading to issues like image jittering under high magnification, vehicle tailing in road scenes, and image blurring in low-light environments due to inadequate aperture control.
Innovation Solution
An intelligent adjustment method that pre-sets corresponding relationships between magnifications and apertures to maintain optimal depth of field, adjusting aperture values within defined ranges and adjusting exposure time and gain accordingly to achieve optimal brightness and depth of field across different scenes and magnifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If aperture is increased to improve depth of field, then depth of field is improved, but image brightness decreases
Solution Approach 1:
The patent applies dynamics by making the aperture value adjustable based on magnification. Instead of using a fixed aperture, the system dynamically changes the aperture according to the current magnification level, allowing optimal depth of field at each magnification while compensating with exposure time and gain adjustments to maintain brightness.
Solution Approach 2:
The patent changes multiple parameters simultaneously - aperture value, exposure time, and gain - to resolve the contradiction. When aperture is adjusted for optimal depth of field, the system compensates by adjusting exposure time and gain to maintain image brightness, thus satisfying both requirements.
2Illumination intensity
If aperture is decreased to improve brightness, then image brightness is improved, but depth of field becomes insufficient
Solution Approach 1:
The system dynamically adjusts aperture based on magnification to ensure optimal depth of field. When magnification increases, aperture is automatically adjusted to maintain depth of field, and exposure time/gain are increased to compensate for reduced light, thus improving brightness without sacrificing depth of field.
Solution Approach 2:
The patent simultaneously adjusts three parameters: aperture value, exposure time, and gain. By coordinating these adjustments, the system can decrease aperture for brightness while compensating with increased exposure time and gain to maintain depth of field, resolving the contradiction.
3Illumination intensity
If exposure time is increased to improve brightness, then image brightness is improved, but image jittering occurs under high magnification
Solution Approach 1:
The patent dynamically adjusts exposure time based on magnification and aperture value. Instead of using a fixed exposure time, the system calculates optimal exposure time considering current magnification and aperture, preventing excessive exposure time at high magnification that would cause jittering while maintaining sufficient brightness.
4Manufacturing precision
If aperture is adjusted for optimal depth of field at high magnification, then depth of field is improved, but image brightness decreases
Solution Approach 1:
The system dynamically adjusts all three parameters (aperture, exposure time, gain) based on magnification. When magnification increases and aperture is adjusted for depth of field, exposure time and gain are simultaneously increased to compensate for reduced light, maintaining brightness while achieving optimal depth of field.
Solution Approach 2:
The patent coordinates changes in aperture value, exposure time, and gain together. By adjusting all three parameters simultaneously based on magnification, the system can optimize depth of field through aperture while compensating with exposure time and gain adjustments to maintain image brightness.
Data Source
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AI summary
The present invention relates to the field of video camera image processing. Disclosed are an intelligent adjustment method when a video camera performs automatic exposure and an apparatus therefor. In the present invention, a first corresponding relationship between a rate and an aperture is pre-set. The first corresponding relationship records corresponding upper and lower aperture limits required by each rate for achieving the best depth of field of an image. The method comprises the following steps: acquiring the current rate of a video camera; searching for upper and lower aperture limits corresponding to the current rate in a first corresponding relationship; if the current aperture value exceeds the range of the searched upper and lower aperture limits corresponding to the current rate, adjusting the current aperture value to be within the range of the upper and lower aperture limits; and according to the adjusted aperture value, adjusting exposure time and gain to satisfy the need of image brightness. In the present invention, according to different field scenario rates, the aperture is adjusted to be within the aperture range corresponding to the best depth of field so as to acquire the best depth of field, and a shutter and gain are adjusted accordingly, so that the best brightness can be ensured and the best depth of field is achieved at the same time so as to improve image quality.