Scanner Image Compensation Using Black White Correction Patterns
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Solution Overview
Problem
Conventional scanners face issues with image quality due to light brightness errors caused by intense scanning light and environmental scattering, which affect the accuracy of gray level adjustments, leading to image distortion.
Innovation Solution
The method involves scanning documents with longitudinal black and white, complete white, or complete black patterns to obtain actual and correctional gray level values, which are then compared to theoretical values to calculate compensational gray level values, thereby adjusting image brightness and compensating for light-related errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If intense light is used for scanning operation, then scanning speed and efficiency are improved, but light brightness errors and scattering increase causing gray level inaccuracy
Solution Approach 1:
The patent applies preliminary action by performing gray level correction before the actual scanning operation. The system scans correction patterns (complete black and complete white patterns) beforehand to obtain correctional gray level values, then uses these values to adjust the gray level of the actual scanned image. This preliminary correction compensates for light brightness errors and scattering effects that would otherwise degrade measurement precision during high-speed scanning.
Solution Approach 2:
The patent implements feedback by comparing the correctional gray level values obtained from scanning correction patterns against expected reference values. The system calculates the difference (error) between measured and expected values, then uses this feedback to adjust and compensate the gray level of the scanned image. This closed-loop feedback mechanism eliminates light brightness errors while maintaining high scanning speed.
2Device complexity
If conventional gray level correction is used, then image processing is simplified, but light scattering and brightness errors cause image distortion
Solution Approach 1:
The patent introduces an intermediary correction process using specific correction patterns (complete black and complete white patterns) that serve as mediators between the light source and the actual image. By scanning these intermediary patterns first and using their gray level values to calculate correction factors, the system compensates for environmental light scattering and brightness errors before processing the actual image, thereby improving image quality without significantly increasing overall system complexity.
Data Source
AI summary
An image compensating method. First, multiple scanning lines are used to scan a document and a longitudinal black and white pattern, in order to produce the actual gray level value for multiple pixels with respect to each of the scanning lines and the document, as well as a correctional gray level value for complete black and a correctional gray level value for complete white with respect to the longitudinal black and white pattern. Then, the compensational gray level value with respect to the actual gray level value for each of the pixels is obtained according to the correctional gray level value for complete black, the correctional gray level value for complete white, the theoretical gray level value for complete black, the theoretical gray level value for complete white, and the actual gray level value for each of the pixels. Then, the procedure is complete.