Image Correction Apparatus for Shading Elimination in OCR
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Solution Overview
Problem
Conventional Optical Character Recognition (OCR) techniques face difficulties in recognizing characters in images taken in ambient lighting or shaded environments due to poor binarization, leading to deteriorated performance and inability to accurately process images with shading.
Innovation Solution
An image correction apparatus and method that divides an image into block units, calculates representative brightness values, generates a background image, and uses a lighting component corrector to eliminate shading from the original image, enhancing image quality and enabling accurate binarization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional binarization is applied to images in ambient lighting or shaded environments, then the OCR process can be executed, but the binarization quality deteriorates leading to poor character recognition
Solution Approach 1:
The patent applies preliminary action by performing lighting component elimination before binarization. The apparatus first divides the image into blocks, calculates representative brightness values, generates a background image representing lighting components, and subtracts this background from the original image to eliminate lighting effects. This preprocessing step ensures that subsequent binarization operates on lighting-corrected images, thereby improving both binarization quality and character recognition accuracy in ambient lighting conditions
2Productivity
If simple conversion to binary values is performed, then the OCR engine can process images, but characters with shade cannot be recognized
Solution Approach 1:
The patent performs preliminary lighting correction before the OCR engine processes the image. By eliminating lighting components and generating a background-subtracted image, the apparatus ensures that characters with shade are properly enhanced and their boundaries are clearly defined. This preprocessing maintains full OCR processing capability while significantly improving character detection accuracy for shaded regions
3Speed
If no lighting correction is applied, then the processing speed is maintained, but the image quality for recognition deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the image into multiple blocks and processing each block independently to calculate representative brightness values. This block-based approach to lighting component elimination reduces computational complexity compared to processing the entire image at once, while still achieving effective lighting correction. The segmented processing maintains acceptable processing speed while significantly improving image quality for character recognition
Data Source
AI summary
An image correction apparatus and method for eliminating a lighting component are provided. A photographed original image is divided into a plurality of block units to calculate a representative brightness value of each of the divided block units. A background image having the size of the original image is generated using the calculated brightness value and interpolation. A lighting component is extracted from the background image and a lighting component included in the original image is eliminated using the extracted lighting component.