Camera Motion Offset Path for Moiré Suppression in Display Imaging
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Solution Overview
Problem
Existing methods for suppressing moiré disturbances in images captured by cameras from display devices suffer from reduced effective spatial resolution and inability to reliably eliminate very low spatial frequencies caused by aliasing, especially when the pixel pitches of the camera's sensor and display device are similar or proportional.
Innovation Solution
A method involving relative movement of the camera or display device along a specific offset path during image capture, which reduces or eliminates moiré disturbances without significantly affecting the spatial resolution, by convolving the camera image with a motion-induced point spread function and applying Fourier transforms to suppress erroneous frequency components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If optical elements are moved relative to the sensor inside the camera to suppress moiré disturbances, then moiré noise is reduced, but the spatial resolution is degraded
Solution Approach 1:
The patent applies dynamics by moving the camera or display device along a predetermined offset path during image capture. This relative movement changes the sampling positions dynamically, which suppresses moiré noise while preserving spatial resolution. The offset path is specifically designed to traverse regions that avoid aliasing artifacts.
Solution Approach 2:
The patent uses preliminary action by pre-calculating and storing multiple candidate offset paths before image capture. These paths are determined based on the pixel pitches of both the camera sensor and display device. During capture, the system selects and executes the appropriate offset path from the pre-computed set, ensuring optimal moiré suppression without trial-and-error adjustments.
2Object-affected harmful factors
If optical defocusing is used to reduce moiré distortion, then moiré noise is suppressed, but the effective spatial resolution is lost
Solution Approach 1:
The patent replaces the optical defocusing mechanism with a mechanical movement approach. Instead of adjusting the optical focus to blur the image (which loses resolution), the system moves the camera or display device along a calculated offset path during capture. This mechanical substitution achieves moiré suppression through spatial sampling variation while maintaining sharp focus and full spatial resolution.
3Object-affected harmful factors
If the pixel pitch of the camera sensor is made equal to the display pixel pitch to avoid moiré, then moiré is avoided, but the measurement setup becomes difficult to achieve in practice
Solution Approach 1:
The patent changes the operational parameters by introducing controlled relative movement along offset paths rather than requiring precise static pixel pitch matching. The system calculates offset paths based on the actual pixel pitches of the camera and display, then moves the camera or display during capture. This parameter change transforms the problem from one requiring precise static alignment to one solved through dynamic sampling variation.
Solution Approach 2:
The patent uses preliminary action by pre-calculating offset paths based on the known pixel pitches of the camera sensor and display device before the measurement takes place. This pre-computation eliminates the need for complex real-time adjustments or precise manual alignment during operation, making the measurement setup much easier to execute while still avoiding moiré artifacts.
Data Source
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AI summary
The invention relates to a method for reducing aliasing errors in a moire-corrected final image formed by at least one camera image, wherein the at least one camera image is captured, by a camera (1) having imaging optics (1.1) and a sensor surface (1.2) with sensor pixels (1.3), as the depiction of a display image of a display device (2) with display pixels (2.1) arranged in a matrix-like manner and spaced apart in a display pixel pitch (D A )<sb /> on the sensor surface (1.2), wherein, during the capture, the camera (1) is shifted relative to the display device (2) along at least one offset path (VP) in relation to a starting position (S). The invention also relates to a method for evaluating the presentation quality of a pixel-based display device (2), and a device for carrying out methods of this type.