Digital Camera Focusing Coordination with Shake Compensation
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Solution Overview
Problem
Conventional digital cameras with hand-tremble compensation devices often experience focusing errors and time delays due to the lack of controlled compensation operations during image stabilization.
Innovation Solution
A digital camera system that includes a shutter-signal generating unit and a digital signal processor to perform centering and compensation operations using a compensation lens or image sensor, driven by a constant DC signal with servo-control, to stabilize images and prevent focusing errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hand-tremble compensation operation is performed during focusing, then camera shake is compensated, but focusing error and time delay occur
Solution Approach 1:
The patent segments the operation into two distinct phases: a first operation period for focusing where the compensation lens is held stationary at a centered position, and a second operation period for image capture where the compensation lens performs hand-tremble compensation. This temporal segmentation resolves the contradiction by preventing the compensation lens from moving during focusing, thereby eliminating focusing error and time delay while still providing image stabilization during capture.
2Reliability
If compensation lens is moved for hand-tremble compensation, then image is stabilized, but focusing operation is disrupted
Solution Approach 1:
The patent applies preliminary action by centering the compensation lens at the beginning of the first operation period before focusing begins. The lens is positioned at a predetermined centered position using a constant DC signal or servo-control, ensuring it is ready and stationary before the focusing operation starts. This preliminary centering prevents any subsequent movement during focusing, thus maintaining both image stabilization capability and focusing speed.
3Device complexity
If no specific control method is used for compensation lens, then device complexity is reduced, but focusing error occurs
Solution Approach 1:
The patent implements a dynamic control strategy where the compensation lens operates in two distinct modes: stationary mode during focusing (first operation period) and active compensation mode during image capture (second operation period). The control system dynamically switches between these modes based on the operational phase, using simple constant DC signals or servo-control only when needed. This dynamic approach maintains focusing accuracy while minimizing overall system complexity.
Data Source
AI summary
In various embodiments, a digital camera may coordinate focusing with compensation of camera shake. The digital camera may include a shutter-signal generating unit which outputs a first shutter signal corresponding to a start of a focusing operation and a second shutter signal corresponding to a start of a photographing operation. The digital camera may also include a digital signal processor which performs a centering operation of a compensation lens in response to the first shutter signal, and which performs a compensation operation of the compensation lens for compensating for a camera shake in response to the second shutter signal.