Image Sensor Movement Control for Peripheral Light-Fall-Off
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Solution Overview
Problem
Conventional image capture apparatuses experience light-fall-off in peripheral areas due to increased movement of the image sensor, which is exacerbated when correcting image blurring, especially in moving images with bright subjects, and enlarging the shutter frame to mitigate this issue increases the apparatus's size, weight, and power consumption.
Innovation Solution
An image capture apparatus with a control method that limits the movement range of the image sensor during image blurring correction to prevent light-fall-off in peripheral areas, using a second image blurring correction mode that prioritizes image quality by restricting the sensor's movement to a range where brightness is maintained, and an interchangeable lens-type digital camera system with a microcomputer controlling the lens unit and shutter mechanism to manage this.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the shutter frame opening is enlarged to reduce light-fall-off in periphery areas, then the light transmission is improved, but the device size, weight, and power consumption increase
Solution Approach 1:
The patent applies partial action by moving the image sensor only within a limited range that prevents light-fall-off in peripheral areas, rather than allowing full unrestricted movement. The control unit calculates a maximum movement range based on aperture size and f-number, restricting the sensor displacement to values that maintain adequate light transmission to peripheral pixels, thus avoiding the need to enlarge the shutter frame opening.
2Illumination intensity
If the shutter frame opening is enlarged to reduce light-fall-off in periphery areas, then the light transmission is improved, but the power consumption increases
Solution Approach 1:
The patent restricts image sensor movement to a calculated maximum range that prevents peripheral light-fall-off, avoiding the need for excessive shutter frame opening enlargement. This partial action approach maintains adequate light transmission while minimizing the power consumption that would result from larger mechanical components and longer shutter curtain travel distances.
3Illumination intensity
If the shutter frame opening is enlarged to reduce light-fall-off in periphery areas, then the light transmission is improved, but the shutter mechanism scale increases
Solution Approach 1:
The patent calculates and enforces a maximum movement range for the image sensor based on aperture size and f-number, restricting sensor displacement to values that prevent peripheral light-fall-off. This approach maintains adequate light transmission without requiring enlargement of the shutter mechanism scale, keeping the system compact and simple.
4Reliability
If the image sensor movement range is increased to improve image blurring correction, then the blur correction effectiveness is improved, but light-fall-off in periphery areas worsens
Solution Approach 1:
The control unit calculates the maximum movement range by considering the aperture size and f-number, then uses this calculated limit as feedback to restrict image sensor displacement. This feedback mechanism ensures that the sensor movement for blur correction does not exceed the threshold that would cause peripheral light-fall-off, maintaining both correction effectiveness and peripheral brightness.
Solution Approach 2:
The patent dynamically adjusts the maximum movement range parameter based on aperture size and f-number conditions. When the aperture is large (small f-number), the maximum movement range is reduced to prevent light-fall-off; when the aperture is small (large f-number), the maximum movement range can be larger. This parameter adaptation resolves the contradiction between blur correction effectiveness and peripheral brightness.
Data Source
AI summary
An image capture apparatus (100) having a correction function that corrects image burring by controlling a position of an image sensor (430) is disclosed. The apparatus controls the correction function in accordance with one of a plurality of modes including a first and second modes. In the first mode, the image sensor (430) can move in a first direction perpendicular to an optical axis of an imaging optical system (201) within a first distance. In the second mode, when an aperture size of a diaphragm (205) in the imaging optical system (201) is greater than or equal to a predetermined value, the image sensor (430) can move in the first direction within a second distance shorter than the first distance.