Abnormal Pixel Detection in Image Reading Devices
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Solution Overview
Problem
Image reading devices struggle to distinguish between abnormal pixels caused by foreign matter and those caused by periodic changes due to lens spacing in white reference data, leading to incorrect judgments.
Innovation Solution
An image reading device with a processor that acquires white reference data from a scanning device with lenses and light-receiving elements, sets each pixel as a target, and determines it as abnormal if the absolute difference with a contrast pixel, separated by an integer multiple of the lens-to-lens distance, exceeds a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional abnormal pixel detection is performed without considering lens spacing periodicity, then detection simplicity is maintained, but detection accuracy deteriorates due to false positives from periodic changes
Solution Approach 1:
The patent applies preliminary action by pre-calculating the lens spacing distance and storing it in memory before the abnormal pixel detection process. The processor retrieves this predetermined value during detection to identify reference pixels at appropriate intervals, avoiding periodic changes. This preparation in advance enables accurate detection without adding complex real-time calculations.
Solution Approach 2:
The patent introduces a reference pixel as an intermediary element in the detection process. By comparing the target pixel with a reference pixel located at a distance corresponding to the lens spacing, the method mediates the detection to eliminate the influence of periodic changes. This intermediary approach allows accurate abnormal pixel identification while maintaining process simplicity.
2Productivity
If white reference data is acquired using a scanning device with multiple lenses, then data acquisition capability is improved, but periodic changes in pixel values occur due to lens spacing
Solution Approach 1:
The patent extracts and isolates the periodic change component from the white reference data by identifying and removing its influence through reference pixel comparison. By separating the periodic variation from the actual pixel values, the method eliminates the harmful effect of lens spacing periodicity while preserving the useful data acquisition capability of the multi-lens scanning device.
Solution Approach 2:
The patent changes the parameter selection by using a predetermined distance corresponding to the lens spacing to locate reference pixels. This parameter transformation converts the problem from dealing with periodic variations at regular intervals to comparing pixels at strategically chosen distances that eliminate periodic effects, thereby stabilizing the pixel values used for abnormal detection.
3Ease of operation
If pixels are compared with adjacent neighbors for abnormal detection, then detection simplicity is maintained, but false abnormal pixel identification occurs due to periodic changes
Solution Approach 1:
The patent applies preliminary action by pre-calculating the lens spacing distance and storing it in memory before the abnormal pixel detection process. The processor retrieves this predetermined value during detection to identify reference pixels at appropriate intervals, avoiding periodic changes. This preparation in advance enables accurate detection without adding complex real-time calculations.
Solution Approach 2:
The patent introduces a reference pixel as an intermediary element in the detection process. By comparing the target pixel with a reference pixel located at a distance corresponding to the lens spacing, the method mediates the detection to eliminate the influence of periodic changes. This intermediary approach allows accurate abnormal pixel identification while maintaining process simplicity.
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
Effectively detects abnormal pixels while minimizing the impact of periodic changes in pixel values caused by lens spacing, improving the accuracy of pixel identification.
Implementation Method 1
a plurality of light-receiving elements arranged in the predetermined direction. The plurality of light-receiving elements is configured to output white reference data including a plurality of pixel values for a plurality of pixels based on a light reflected from the white reference member
Data Source
AI summary
An image reading device includes a white reference member, reading device, and processor. The reading device includes lenses and light-receiving elements. The light-receiving elements output a plurality of pixel values based on a light reflected from the white reference member. Each lens corresponds to at least two light-receiving elements. Each light-receiving element is configured to receive a light reflected from the white reference member and passing through the corresponding lens and to output one pixel value. The processor acquires the pixel values by using the reading device, sets a target pixel, and determines that the target pixel is an abnormal pixel when an absolute value of difference between a pixel value of the target pixel and a pixel value of a first pixel is greater than a prescribed threshold. The first pixel is separated from the target pixel by an integer multiple of the predetermined lens-to-lens distance.