Object-Based Sharpening Filter for Webcam OCR

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Solution Overview

Problem

Existing OCR systems require specialized hardware, such as close-focused cameras, which are cumbersome and costly, and existing webcams or laptop cameras produce defocused images at close ranges, making them unsuitable for business card OCR without pre-processing.

Innovation Solution

A method involving object-based sharpening filters and block-wise quantization is applied to defocused images from existing webcams or laptop cameras to enhance image quality for accurate OCR, allowing the use of built-in cameras for business card recognition without additional hardware.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If specialized close-focused camera hardware is used, then image focus quality is improved, but device complexity and cost increase

Engineering Contradiction:
Improveimage focus qualityVSAvoidhardware complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical/optical solution (specialized close-focused camera hardware) with a software-based image processing solution. By applying deconvolution algorithms and sharpening filters to defocused images captured by standard webcams, the system achieves comparable OCR accuracy without requiring specialized camera hardware, thereby reducing device complexity and cost.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If standard webcam is used, then device complexity is reduced, but image focus quality deteriorates at close range

Engineering Contradiction:
Improvehardware simplicityVSAvoidimage focus quality
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary image processing actions (deconvolution, sharpening filters, contrast enhancement) to the defocused image data before OCR processing. By pre-processing the blurry images captured by standard webcams with algorithms that reverse blur effects and enhance edges, the system compensates for the poor focus quality and enables accurate character recognition.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If defocused image processing is applied, then adaptability of existing cameras is improved, but processing time increases

Engineering Contradiction:
Improvecamera compatibilityVSAvoidprocessing time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent segments the image processing task into distinct stages: initial deconvolution to reverse blur, followed by sharpening filter application, then contrast enhancement, and finally OCR processing. This segmentation allows each processing stage to be optimized independently and enables parallel processing where applicable, reducing overall processing time while maintaining adaptability to images from various camera sources.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS8457423B2Object-based optical character recognition pre-processing algorithm
Publication Date: 2013.06.04 OMNIVISION TECHNOLOGIES INC
  • US8457423B2 patent drawing
  • US8457423B2 patent drawing
  • US8457423B2 patent drawing

AI summary

A method of pre-processing a defocused image of an object includes applying an object-based sharpening filter on the defocused image to produce a sharper image; and quantizing the sharper image using block-wise quantization. A system for generating decoded text data from alphanumeric information printed upon an object includes a camera that obtains image data of the alphanumeric information. The system also includes a pre-processor that (a) performs block-wise quantization of the image data to form conditioned image data, and (b) performs optical character recognition on the conditioned image data to generate the decoded text data.