Binarization Processor Dynamic Threshold Adjustment for Skin Color Tracking
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Solution Overview
Problem
Target tracking systems face challenges in dynamically controlling threshold values under varying illuminance and light source conditions, leading to failures in target extraction, especially with human skin colors, due to the lack of feedback mechanisms and difficulties in handling flicker and color changes in high-frame-rate imaging.
Innovation Solution
An image processing system with a binarization processor that includes a color-specific multiplier, adjuster, and driving information generator, which adjusts color levels and calculates ratios to enhance target extraction accuracy, suppresses flicker and color changes by integrating and feeding back periodic brightness changes, and performs auto white balance and exposure adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed threshold value is used for binarization, then the device complexity is low, but the target extraction accuracy deteriorates under varying illuminance and light source conditions
Solution Approach 1:
The patent implements dynamic threshold adjustment by introducing a feedback mechanism that calculates the standard deviation of pixel values and adapts the threshold value in real-time based on image content characteristics. This resolves the contradiction by making the threshold dynamic rather than fixed, improving extraction accuracy under varying conditions while maintaining reasonable system complexity through efficient statistical calculations
Solution Approach 2:
The patent employs a feedback mechanism where the binarization result is evaluated and the threshold is adjusted based on the standard deviation of pixel values and the distribution of foreground/background pixels. This feedback loop continuously optimizes the threshold to maintain high extraction accuracy while adapting to changing illuminance and light source conditions
2Productivity
If the frame rate is increased for high-speed tracking, then the tracking speed is improved, but flicker and color changes become more pronounced
Solution Approach 1:
The patent addresses flicker by implementing periodic compensation based on the known frequency characteristics of light sources. By detecting and compensating for periodic brightness variations at the increased frame rate, the system maintains stable color and brightness representation even when capturing at high speeds
Solution Approach 2:
The patent dynamically adjusts processing parameters including threshold values, color balance corrections, and exposure compensation based on real-time analysis of image statistics. These parameter changes adapt to the specific conditions at each frame, maintaining stability despite high-frame-rate operation
3Measurement precision
If color-specific processing is added to handle skin tones, then the target extraction accuracy for human subjects is improved, but the processing time increases
Solution Approach 1:
The patent segments the color processing into specific channels (e.g., skin tone detection in L*a*b* color space) and applies targeted processing only where needed. This selective approach improves skin color extraction accuracy while minimizing overall processing time by avoiding full-color-space processing of all pixels
Data Source
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AI summary
An image processor according to the present disclosure includes: a multiplier that receives image data from a pixel section including pixels of a plurality of colors and multiplies the image data by an adjustment parameter that adjusts a color level in each of the pixels; an adjuster that calculates a ratio of respective colors in each of the pixels in the image data and adjusts a value of the adjustment parameter on the basis of the ratio of the respective colors; and a binarization processor that extracts a target image of a specific color on the basis of the image data multiplied by the adjustment parameter.