Imaging Apparatus Frame Rate Change Exposure Control
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Solution Overview
Problem
Conventional imaging apparatus struggle to maintain smooth image reproduction when changing frame rates, as automatic exposure control often results in inadequate exposure control values, leading to image darkening and noise generation due to uniform correction of aperture, shutter speed, and amplification factor.
Innovation Solution
The imaging apparatus includes an exposure control unit that adjusts shooting parameters such as exposure time and lens aperture value based on object brightness, with specific control conditions for changing frame rates, particularly narrowing the change in lens aperture value to prevent image quality deterioration and noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If uniform correction of exposure control values (aperture value, shutter speed, amplification factor) is applied when frame rate changes, then image brightness can be maintained, but image quality deteriorates and noise increases
Solution Approach 1:
The patent segments the exposure control values into different categories (aperture value, shutter speed, amplification factor) and applies different correction strategies to each. Specifically, it narrows the change range of aperture value while allowing other parameters to be corrected uniformly, thereby preventing image quality deterioration and noise generation while maintaining brightness.
Solution Approach 2:
The patent applies local quality by treating different exposure control parameters differently based on their specific characteristics. The aperture value is given special treatment with narrowed change range to prevent mechanical noise, while other parameters like shutter speed and amplification factor are corrected more freely to maintain overall image brightness and quality.
2Adaptability or versatility
If aperture value changes frequently to maintain exposure, then exposure control is flexible, but driving noise increases
Solution Approach 1:
The patent implements dynamic control of aperture value changes by introducing a frame rate change detection mechanism. When frame rate changes are detected, the system dynamically narrows the aperture value change range. This dynamic adjustment reduces unnecessary aperture operations and associated driving noise while maintaining exposure control flexibility through other parameters.
Solution Approach 2:
The patent uses feedback from frame rate change detection to control aperture value adjustments. The system monitors frame rate changes and provides feedback to the exposure control unit, which then adjusts the aperture value change range accordingly. This feedback mechanism prevents excessive aperture operations and reduces driving noise.
3Productivity
If exposure time shortens with increased frame rate, then more frames per second are captured, but image brightness decreases
Solution Approach 1:
The patent applies parameter changes by adjusting multiple exposure control parameters (aperture value, shutter speed, amplification factor) in response to frame rate changes. When frame rate increases and exposure time shortens, the system corrects these parameters to compensate for brightness loss, thereby maintaining image brightness while achieving higher frame rates.
Data Source
AI summary
The invention is provided to perform exposure control that uses a diagram for monitor-through in a shooting waiting state in which the output frame rate of an image sensor is set into 30 fps and that for high-speed movie recording is performed during move images shooting with the high-speed movie mode in which the output frame rate is set into 300 fps. Upon shifting to exposure control at the high-speed movie mode, the aperture value to be first set is determined uniquely from the current LV value by using a program diagram for preparing to start high-speed movie recording in which the space scale of the program diagram for monitor-through is converted into a space scale similar to that of the diagram for high-speed movie recording. Then, the exposure adjustment that sets the determined aperture value, and the shutter speed and the gain corresponding to thereof as exposure control values.