Image Reading Apparatus Spectral Color Tone Correction
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Solution Overview
Problem
Current image reading and forming apparatuses face challenges in accurately correcting color tones and detecting image quality defects due to limitations in measuring spectral distribution and brightness variations across images.
Innovation Solution
An image reading apparatus equipped with a line sensor and spectroscope that reads images and color reference patches, generating color tone correction data by measuring spectral distribution and correcting for brightness and shading issues using a computational unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spectral distribution measurement is performed to correct color tones, then color tone accuracy is improved, but measurement time and processing complexity increase
Solution Approach 1:
The system performs preliminary spectral distribution measurements of reference patches during the image formation process. By measuring reference patches that are formed alongside the main image on the same sheet, the system obtains spectral data in advance for color tone correction, eliminating the need for separate measurement steps and reducing overall measurement time.
Solution Approach 2:
The measurement process is segmented into measuring only specific reference patches rather than the entire image. The spectroscope measures spectral distribution of predetermined reference patches (color references) that are strategically placed on the sheet, allowing selective measurement of critical color information without measuring the complete image area, thus reducing measurement time while maintaining color accuracy.
2Measurement precision
If spectral distribution measurement is performed to correct color tones, then color tone accuracy is improved, but device complexity increases
Solution Approach 1:
The system uses predetermined reference patches as intermediaries between the image formation process and spectral measurement. These reference patches serve as standardized mediators that capture illumination and sheet characteristics, allowing the spectroscope to indirectly measure the conditions affecting the main image without directly measuring the complex image content itself, thereby simplifying processing.
Solution Approach 2:
The system changes the measurement parameters by focusing solely on spectral distribution of reference patches rather than analyzing complete image data. By measuring only the spectral characteristics of known reference patches and comparing them against stored reference data, the system reduces computational complexity while maintaining color tone correction accuracy through targeted spectral parameter analysis.
3Stability of the object's composition
If reference patches are measured for brightness correction, then brightness uniformity is improved, but measurement precision requirements increase
Solution Approach 1:
The system uses homogeneous reference patches with known, uniform spectral characteristics as measurement targets. These predetermined reference patches provide a consistent, uniform basis for brightness measurement that eliminates variations caused by measuring heterogeneous image content, thereby reducing the precision requirements while still achieving accurate brightness uniformity correction across the image.
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 apparatus effectively corrects color tones and detects image quality defects by accurately measuring spectral distribution and brightness variations, ensuring precise image formation and quality control.
Implementation Method 1
a spectroscope which has a visual field encompassing multiple patches for correcting color tones formed on the sheet and arranged in the sheet transport direction, and which measures the spectral distribution of each patch
Implementation Method 2
a line sensor that reads, from the sheet being transported, an image formed on the sheet, and in addition, reads the part of the reference reflecting member in proximity to the sheet in the sheet width direction
Implementation Method 3
an illuminating unit that illuminates the reference reflecting member and the sheet passing through
Data Source
AI summary
An image reading apparatus includes an image reading unit and a computational unit. The image reading unit includes a reference reflecting member that acts as a color reference, an illuminating unit that illuminates a part of the reference reflecting member and a sheet being transported in proximity thereto, a line sensor that reads an image formed on the sheet and the part of the reference reflecting member in proximity to the sheet in the sheet width direction, and a spectroscope that measures the spectral distribution of each of multiple patches for correcting color tones formed on the sheet and arranged in the sheet transport direction. The computational unit generates color tone correction data by performing computations based on the spectral distribution of each patch measured by the spectroscope, and the read values of the reference reflecting member obtained by the line sensor.