Aperture Diaphragm Control for Apodization and Shutter Speed
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Solution Overview
Problem
Existing aperture diaphragm control systems face challenges in achieving high-speed operation due to inertial and frictional forces, making it difficult to obtain an apodization effect at increased shutter speeds, especially in high-light environments, and are susceptible to hand movement and exposure unevenness.
Innovation Solution
The system dynamically controls the aperture diaphragm by moving it from a starting position to first and second positions during the exposure period, with an acceleration phase before exposure to minimize preliminary diaphragm driving and reduce exposure unevenness, using a diaphragm drive motor to alternate between diaphragm positions for each frame or exposure section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stepping motor is used to drive the aperture diaphragm, then the apodization effect can be obtained, but the aperture diaphragm cannot operate at high speed due to inertial force and frictional force
Solution Approach 1:
The aperture diaphragm is driven to a preliminary position before the exposure period starts, so that when exposure begins, the diaphragm is already at or near the required position, eliminating the need for high-speed operation during exposure and overcoming inertial and frictional forces
Solution Approach 2:
The diaphragm driving process is divided into multiple stages: a preliminary driving stage before exposure to reach the first diaphragm position, and a main exposure stage where the diaphragm moves from the first position to the second position during exposure, allowing optimized speed control for each stage
2Reliability
If the aperture diaphragm is slowly opened to secure sufficient driving amount, then the apodization effect can be achieved, but shutter speed must be slowed down
Solution Approach 1:
The aperture diaphragm is positioned in advance before exposure begins, so the full exposure time can be used for image capture without being consumed by diaphragm movement, thereby maintaining high shutter speed while achieving the apodization effect
Solution Approach 2:
The diaphragm control system dynamically adjusts the timing and position of the aperture diaphragm, transitioning from static pre-positioning to dynamic movement during exposure, enabling both high shutter speed and apodization effect
3Reliability
If the aperture diaphragm moves during exposure, then the apodization effect can be obtained, but exposure unevenness occurs
Solution Approach 1:
The aperture diaphragm is designed with non-uniform transmittance characteristics where the center has high transmittance and the periphery has gradually decreasing transmittance, creating the apodization effect through local property variation rather than uniform movement
Solution Approach 2:
The aperture diaphragm reaches its first position before exposure starts and maintains this position or moves predictably during exposure, reducing unexpected variations and exposure unevenness caused by rapid movement
Data Source
AI summary
An image processing apparatus including circuitry configured to cause an aperture diaphragm to move from a starting position toward first and second diaphragm positions of the aperture diaphragm such that the aperture diaphragm reaches the first diaphragm position at the beginning of an exposure period. The circuitry is further configured to cause the aperture diaphragm to move from the first diaphragm position to the second diaphragm position during the exposure period.