Image Processing Device Litter Shadow Detection

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Solution Overview

Problem

Existing image processing technologies for digital cameras face challenges in efficiently and accurately detecting and correcting litter shadows, often requiring substantial processing capabilities and leading to erroneous detections due to changes in brilliance caused by subject coloring, and struggle with accurately identifying foreign objects on optical components.

Innovation Solution

An image processing device comprising a brilliance gradient computation unit, color phase value computation units, and a region extraction unit that computes and compares brilliance and color phase values within and surrounding candidate regions to accurately identify and extract litter shadows and foreign objects, using inverse-gamma-corrected image information and HSV color system for efficient processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If litter shadow correction is performed based on standard image using multiple images, then correction accuracy is improved, but processing complexity and processing time increase substantially

Engineering Contradiction:
Improvelitter shadow detection accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts only the necessary brightness information from a single image to detect litter shadows, rather than processing multiple images. The brightness computation unit calculates brightness values directly from the captured image data, and the litter shadow detection unit identifies shadows by comparing local brightness variations, thereby extracting only the essential information needed for detection without the complexity of multi-image processing

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention segments the image processing into distinct functional units: a brightness computation unit that calculates brightness values, and a litter shadow detection unit that detects shadows based on brightness variations. This segmentation allows each unit to perform its specific function efficiently, reducing overall processing complexity while maintaining detection accuracy

Inventive Principle:
Principle #1Segmentation

2Productivity

If litter shadow is extracted based on brilliance information change, then extraction speed is improved, but erroneous detection increases due to subject coloring changes

Engineering Contradiction:
Improveextraction speedVSAvoiddetection accuracy
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention applies local quality analysis by computing brightness values for specific regions and comparing them to determine litter shadows. The litter shadow detection unit analyzes local brightness variations in different regions of the image, comparing brightness values between adjacent regions to identify shadows while being insensitive to global color changes. This local comparison approach maintains extraction speed while improving reliability by focusing on relative brightness differences rather than absolute brilliance values

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the parameter used for detection from brilliance information (which is sensitive to color changes) to brightness information (which represents luminance). By computing brightness values that are less sensitive to color variations and more focused on luminance differences, the system maintains extraction speed while reducing erroneous detections caused by subject coloring changes

Inventive Principle:
Principle #35Parameter changes

3Productivity

If conventional brightness-based detection is used, then processing load is reduced, but detection accuracy decreases due to inability to distinguish litter shadows from subject variations

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidlitter shadow detection precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The invention implements feedback by comparing brightness values between different regions and using this comparison information to refine litter shadow detection. The litter shadow detection unit receives brightness values from the brightness computation unit and uses the differences between adjacent region brightness values to identify litter shadows, providing feedback that improves detection precision while maintaining processing efficiency

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS8665347B2Image processing device, image processing program, and imaging device computing brightness value and color phase value
Publication Date: 2014.03.04 MAXELL LTD
  • US8665347B2 patent drawing
  • US8665347B2 patent drawing
  • US8665347B2 patent drawing

AI summary

An image processing device comprises: a brilliance gradient computation unit computing a brilliance gradient within an image based on an image information; a color phase value computation unit computing a first color phase value and a second color phase value, the first color phase value representing a color phase inside a candidate region determined based on the brilliance gradient computed by the brilliance gradient computation unit, the second color phase value representing a color phase in a region surrounding the candidate region; and a region extraction unit extracting a region from the candidate region such that a difference between the first color phase value and the second color phase value is less than or equal to a predetermined threshold value.