Image Graininess Evaluation Using Entropy of Blurred Pixel Differences

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Solution Overview

Problem

Existing image evaluation techniques require a comparative image and are not effective in evaluating image graininess regardless of image size, necessitating a method to objectively assess image graininess using only the evaluation-target image.

Innovation Solution

An image evaluation device comprising a blurer, differentiator, scanner, and calculator that creates a blurred image, calculates pixel value differences, and computes entropy from these differences to determine the graininess of an image, allowing for scanning along various paths including left-to-right, top-to-bottom, and space-filling curves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a comparative image is used to evaluate image graininess, then the evaluation can be performed, but the evaluation process becomes complex and requires additional image data

Engineering Contradiction:
Improveimage graininess evaluationVSAvoidevaluation process
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the necessary information from the image (pixel value differences after blurring) to evaluate graininess, eliminating the need for complex comparative image processing while maintaining evaluation accuracy

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The evaluation method uses only the evaluation-target image itself (by creating a blurred version of it) to determine graininess, making the system self-sufficient without requiring external comparative images or additional data

Inventive Principle:
Principle #25Self-service

2Measurement precision

If traditional evaluation methods are used, then image graininess can be assessed, but the evaluation is affected by image size variations

Engineering Contradiction:
Improveimage graininess assessmentVSAvoidimage size independence
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the parameter of image representation by using pixel value differences in a blurred image, which creates a size-independent metric for graininess evaluation that works consistently across different image dimensions

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If multiple images are evaluated for selection, then the best image can be chosen, but the evaluation time and computational resources increase

Engineering Contradiction:
Improveimage selection accuracyVSAvoidevaluation speed
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies partial action by using only the essential blurring and pixel difference calculation steps needed for graininess evaluation, avoiding excessive processing while maintaining sufficient accuracy for effective image selection

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS9330447B2Image evaluation device, image selection device, image evaluation method, recording medium, and program
Publication Date: 2016.05.03 RAKUTEN GROUP INC
  • US9330447B2 patent drawing
  • US9330447B2 patent drawing
  • US9330447B2 patent drawing

AI summary

An image evaluation device (101) properly evaluating the graininess (or roughness) of an image is provided. The blurer (102) creates a second image b by blurring a first image a. The differentiator (103) creates a third image c presenting the difference between the first image a and second image b. The pixel value of each pixel of the third image c presents the difference in pixel value between the pixels at the same position in the first image a and second image b. The scanner (104) scans the pixels contained in the third image c, obtains the differences in pixel value between adjoining pixels, and obtains the respective probabilities of occurrence of the differences. The calculator (105) calculates the entropy from the obtained, respective probabilities of occurrence of the differences. The outputter (106) outputs the entropy as the evaluation value of the graininess (or roughness) of the first image.