CMOS Image Sensor Defective Pixel Correction via Weighted Averaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
CMOS-type imaging elements in digital cameras are prone to blooming, where white defects expand to adjacent pixels, leading to unnatural correction results and prolonged photography times when attempting to specify and correct defective pixels.
Innovation Solution
An image processing device that specifies the position of defective pixels, identifies regions affected by image noise, and corrects pixel values using a weighted average of peripheral pixel values, allowing for accurate and effective correction of image data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If correction is performed based on pixel values before and after the defective pixel, then the correction process is simple, but the correction result becomes unnatural due to blooming expansion to adjacent pixels
Solution Approach 1:
The patent segments the correction process into two distinct stages: first identifying the defective pixel position, then determining the blooming-affected region based on distance from the defective pixel. This segmentation allows different correction strategies to be applied to different regions, improving correction naturalness while maintaining process simplicity.
Solution Approach 2:
The patent applies local quality by determining correction methods based on the spatial relationship between pixels and the defective pixel. Pixels within the blooming-affected region (within distance d) receive different correction treatment compared to pixels outside this region, ensuring that correction results are natural and account for the localized nature of blooming effects.
2Measurement precision
If a second photography action is performed to specify defective pixels accurately, then the accuracy in specifying defective pixels is improved, but the overall photography time becomes too long
Solution Approach 1:
The patent performs preliminary action by identifying and storing the positions of defective pixels in advance, before the actual photography action. This allows the system to quickly determine which pixels are affected by blooming during image processing without requiring additional photography actions, thus maintaining high accuracy while avoiding time loss.
Solution Approach 2:
The patent introduces an intermediary mechanism (distance calculation based on coordinates) to determine blooming-affected regions. By using the distance d between the defective pixel and other pixels as an intermediary criterion, the system can accurately identify affected pixels without requiring a second photography action, thereby maintaining accuracy while reducing time consumption.
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
The solution enables accurate and efficient correction of pixel values affected by blooming, ensuring natural image quality without significantly increasing photography time.
Implementation Method 1
the light incident from a lens is converted to electrical signals by way of an imaging elements CMOS (Complementary Metal Oxide Semiconductor) or CCD (Charge Coupled Device) type
Data Source
AI summary
A digital camera (1) includes: an imaging unit (16) having an imaging element that includes a plurality of pixels, and generates a pixel value for each of the plurality of pixels as image data; a position specification unit (53) that specifies a position of a defective pixel among the plurality of pixels, in the image data generated by the imaging unit (16); a region specification unit (54) that specifies a region in the image data in which image noise occurs due to the defective pixel, based on the position specified by the position specification unit (53); and a correction unit (55) that corrects a pixel value of each of a plurality of pixels included in the region in the image data specified by the region specification unit (54), based on a weighted average of pixels values of a plurality of pixels located at a periphery of the region.