Moire Pattern Removal via Optical Path Adjustment
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Solution Overview
Problem
Digital imaging devices often produce moire patterns due to their grid structure, leading to undesirable irregular images, and existing methods either require additional hardware or reduce image sharpness by performing unnecessary filtering.
Innovation Solution
A method and apparatus that detect the presence of a moire pattern by analyzing the image frequency and spatial frequency of a preview image, and adjust the optical path of light incident to the image sensor to perform low-pass filtering only when necessary, using an optical filter or total reflection prism to change the light path by at least one pixel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an optical low-pass filter (OLPF) is used to remove moire pattern, then moire pattern is removed, but the size of optical system increases and image sharpness deteriorates
Solution Approach 1:
The invention extracts and removes only the harmful moire pattern frequency components from the image signal through digital signal processing, while leaving the rest of the optical system unchanged. This avoids adding bulky optical filters while eliminating the specific harmful interference pattern.
Solution Approach 2:
The invention replaces the mechanical/optical low-pass filter with a digital signal processing approach. Instead of using physical optical components to filter light, the system uses digital filtering algorithms to remove moire patterns from the captured image signal, thereby eliminating the need for additional optical elements.
2Object-affected harmful factors
If an optical low-pass filter (OLPF) is used to remove moire pattern, then moire pattern is removed, but image sharpness deteriorates
Solution Approach 1:
The invention applies filtering action selectively and partially - only to the specific frequency ranges where moire patterns occur, rather than applying a broad low-pass filter that would blur all high-frequency image details. This targeted approach removes moire patterns while preserving image sharpness.
Solution Approach 2:
The invention replaces the mechanical/optical low-pass filter with a digital signal processing approach. Instead of using physical optical components to filter light, the system uses digital filtering algorithms to remove moire patterns from the captured image signal, thereby eliminating the need for additional optical elements.
3Object-affected harmful factors
If image data is processed in a digitized manner to remove moire pattern, then moire pattern is removed, but overall performance of digital imaging device is reduced
Solution Approach 1:
The invention applies filtering action selectively and partially - only to the specific frequency ranges where moire patterns occur, rather than applying a broad low-pass filter that would blur all high-frequency image details. This targeted approach removes moire patterns while preserving image sharpness.
4Object-affected harmful factors
If filtering is always performed to remove moire pattern, then moire pattern is removed, but resolution is deteriorated
Solution Approach 1:
The invention applies filtering action selectively and partially - only to the specific frequency ranges where moire patterns occur, rather than applying a broad low-pass filter that would blur all high-frequency image details. This targeted approach removes moire patterns while preserving image sharpness.
Solution Approach 2:
The invention applies different processing characteristics to different frequency regions of the image signal. High-frequency components corresponding to moire patterns are filtered, while other high-frequency components containing fine image details are preserved, creating locally optimized quality across different frequency bands.
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
Effectively removes moire patterns without deteriorating image resolution, ensuring clear images and eliminating the need for additional image correction procedures.
Implementation Method 1
The optical path adjusting unit may include an optical filter or total reflection prism and the optical path may be changed by the rotation of the optical filter or the total reflection prism.
Implementation Method 2
a method using an optical low-pass filter (OLPF), that is, a birefringent device, is used to remove a moire pattern. In this method, incident light is divided into more than two light beams with different refraction angles by using the OLPF
Data Source
AI summary
An apparatus for and a method of removing a moire pattern of a digital imaging device are provided. It is determined whether or not a moire pattern is created based on an image frequency of a preview image and a spatial frequency of an image sensor, and when it is determined that a moire pattern is generated, an optical path of light incident to an image sensor is slightly changed to remove the moire pattern. Accordingly, image quality deterioration can be improved, and a problem of unnecessary filtering that causes deterioration of resolution even when there is no moire pattern can be enhanced.