Image Processing Circuit Board Invalid Area Data Replacement
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Solution Overview
Problem
Conventional image reading devices face issues with image quality deterioration due to misalignment of document settings, leading to undefined output values in invalid areas, resulting in image streaks and poor registration adjustments in the scanning directions.
Innovation Solution
An image processing circuit board that subtracts output from an image sensor when no input light is received, discriminates between effective and invalid areas, and converts invalid area data into a predetermined output value, using a data replacement unit to improve image quality by fixing invalid pixel periods to a background or white value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If black correction is performed by subtracting image sensor output when no input light is received, then image quality in effective areas is improved, but undefined output values in invalid areas cause image streaks and deterioration
Solution Approach 1:
The patent divides the image sensor output into two segments: valid pixel data and invalid pixel data. By separating these segments and applying different processing rules, the system maintains high image quality in valid areas while preventing streaks in invalid areas. The invalid pixel period is identified and handled differently from the valid pixel period, eliminating the harmful effect of undefined values.
Solution Approach 2:
The patent converts the potentially harmful undefined output values in invalid areas into a beneficial fixed value (alpha value). By replacing the harmful undefined data with a predetermined value, the system transforms what would be a source of image streaks into a neutral element that does not degrade image quality.
2Manufacturing precision
If registration adjustment is performed after device assembly, then alignment accuracy is improved, but component assembly position deviations cause misalignment in scanning directions
Solution Approach 1:
The patent changes the parameter handling approach for invalid pixel data by introducing an alpha value (predetermined value). This parameter substitution ensures that even when registration adjustments are made to compensate for assembly deviations, the invalid areas do not produce inconsistent or undefined results, maintaining reliability across different scanning positions.
3Productivity
If invalid pixel period data is output directly, then data processing speed is maintained, but image quality deteriorates due to undefined output values
Solution Approach 1:
The patent performs preliminary action by identifying and marking the invalid pixel period before final image output. By预先 determining which pixels are invalid and replacing them with alpha values in advance, the system maintains processing efficiency while ensuring image quality is not compromised by undefined values in the final output.
Data Source
AI summary
An image processing circuit board, a reading device, an image forming apparatus, an image processing method, and an image processing device. The image processing circuit board subtracts output of an image sensor when no input light is received, from output of a reading device that reads image data of a subject using the image sensor, discriminates between effective area and invalid area of the image data output by the reading device, and converts the image data of the invalid area into a predetermined output value after the output of the image sensor when no input light is received is subtracted from the output of the reading device.