Contact Image Sensor Pixel Interpolation with Sensitivity Correction
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Solution Overview
Problem
Conventional image scanners face challenges in accurately interpolating missing pixels due to variations in sensitivity and characteristics of imaging devices in contact image sensors, particularly when scanning highly periodic images, leading to degraded image quality.
Innovation Solution
An image scanner system with a compensator unit to correct for variations in imaging device characteristics, followed by an interpolator unit that performs interpolation on the corrected data, using a combination of mean preserving interpolation circuits to accurately fill in missing pixel data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If linear interpolation or higher degree function interpolation is performed at points where imaging devices are not evenly spaced, then interpolation data can be calculated, but correct interpolation is impossible due to variations in sensitivity or other characteristics of individual imaging devices, resulting in degraded quality of scanned images
Solution Approach 1:
The patent applies preliminary action by performing sensitivity correction on the imaging devices before conducting interpolation. The correction unit adjusts the sensitivity variations of individual imaging devices in advance, ensuring that the input data for interpolation is already corrected. This preliminary correction enables subsequent interpolation to achieve both accuracy and reliability, particularly for highly periodic images where uncorrected sensitivity variations would cause large errors.
2Productivity
If highly periodic images are scanned with conventional interpolation methods, then scanning can be performed, but large interpolation errors occur, greatly degrading the quality of the scanned images
Solution Approach 1:
The patent applies preliminary action by performing sensitivity correction on the imaging devices before conducting interpolation. The correction unit adjusts the sensitivity variations of individual imaging devices in advance, ensuring that the input data for interpolation is already corrected. This preliminary correction enables subsequent interpolation to achieve both accuracy and reliability, particularly for highly periodic images where uncorrected sensitivity variations would cause large errors.
Data Source
AI summary
Interpolation data for a missing pixel are obtained (4) after a correction (3) for variations in the characteristics of the imaging devices (8(1), 8(2)). The correction for variations in characteristics includes, for example, a black level correction (9) and a sensitivity correction (10). The interpolation includes, for example, interpolation calculations (14(1), 14(2)) such that a mean value of a plurality of pixels including the missing pixel and a mean value of a plurality of pixels not including the missing pixel become equal and an interpolation calculation (14(0)) that takes the mean of the pixels to the right and left of the missing pixel, the calculation with the least error being selected (13, 15). Thus missing pixels in highly periodic images can be properly interpolated, and interpolation can be performed with high precision even when there are variations in the sensitivity characteristics of the individual imaging devices constituting the contact image sensor.