Photographing Apparatus LPF Control for Moire and False Color
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Solution Overview
Problem
Digital cameras face issues with moire and false color in specified photographing modes and live-view mode, where the optical low-pass filter (LPF) function either fails to remove these artifacts or exacerbates them, leading to unnatural images due to synchronization issues between frame exposure and sensor drive frequency, and limitations in high-speed shutter operation.
Innovation Solution
A photographing apparatus and method that includes an image sensor and a driver to obtain an optical low-pass filter effect by moving a movable member, such as a lens element, in a direction orthogonal to the optical axis, with a processor controlling the LPF effect based on the photographing mode, allowing the effect only in still-image mode and disabling it in specified modes like movie-shooting and HDR to prevent moire and false color issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the LPF function is activated by driving the image sensor in specified photographing modes or live-view mode, then moire and false color are not removed, but the artifacts are accentuated causing unnatural images
Solution Approach 1:
The patent dynamically adjusts the LPF function activation based on the photographing mode. The control unit determines whether to activate the LPF function by detecting the current photographing mode, enabling it only in still-image mode and disabling it in specified modes like movie-shooting and HDR modes, thereby adapting the system behavior to different operational contexts
Solution Approach 2:
The patent changes the operational parameter of the LPF function (activation state) based on the photographing mode. By switching the driving of the image sensor on or off depending on the mode, the system optimizes image quality for each specific photographing scenario
2Object-affected harmful factors
If the LPF function is activated in movie-shooting mode, then time-periodic false color occurs due to synchronization issues between frame rate and sensor driving frequency
Solution Approach 1:
The system dynamically controls the LPF function activation based on the photographing mode. In movie-shooting mode, the control unit detects the mode and disables the LPF function by preventing image sensor driving, thereby avoiding the generation of time-periodic false color artifacts that would result from frequency synchronization issues
3Object-affected harmful factors
If the LPF function is activated in HDR photographing mode, then the image sensor driving cannot keep up with high-speed shutter, but moire removal effect is reduced causing unnatural HDR processed image
Solution Approach 1:
The control unit dynamically adjusts the LPF function activation based on the photographing mode. In HDR mode, the system detects the mode and disables image sensor driving for LPF, recognizing that the high-speed shutter operation cannot synchronize with the sensor driving frequency, thereby preventing degradation of HDR image quality
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables high-quality still images with moire and false color removal in still-image mode and reduces their adverse impact in specified modes, ensuring reliable image quality by selectively activating the LPF effect only when necessary.
Implementation Method 1
an image sensor, which converts an object image that is formed by a photographing optical system into electrical pixel signals
Implementation Method 2
a driver configured to obtain an optical low-pass filter effect via an object light-bundle being incident on a plurality of pixels, having different detection colors, of the image sensor by moving a movable member (shake-correction member) in a direction that is different from an optical axis
Data Source
AI summary
In the photographing apparatus and the photographing control method, a processor can set one of a still-image photographing mode, and a specified photographing mode other than the still-image photographing mode. An LPF controller allows the optical low-pass filter effect to be obtained by moving the movable member via a driver when the processor has set a photographing mode to the still-image photographing mode, and prohibits an obtaining of the optical low-pass filter effect, obtained by moving the movable member via the driver, when the processor has set the photographing mode to the specified photographing mode.