Video Analysis Autogain Filter Using Texture Correlation
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Solution Overview
Problem
Current video surveillance systems face challenges in accurately distinguishing between foreground and background pixels due to automatic gain control effects, which can lead to incorrect object tracking and behavior analysis.
Innovation Solution
A method that extracts foreground patches from video frames using a background model, determines texture correlation scores, and removes pixels with high correlation scores to filter out false-positive foreground pixels caused by autogain, thereby refining the analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If automatic gain control is used to improve dynamic range in low-light conditions, then image quality for human observers is improved, but the video analysis system's ability to distinguish foreground from background pixels deteriorates
Solution Approach 1:
The patent segments the video frame into foreground and background regions using a background model, then applies texture analysis specifically to identify and remove false foreground pixels caused by autogain effects. This segmentation approach allows differential processing that preserves true foreground objects while eliminating autogain artifacts.
Solution Approach 2:
The patent applies local texture analysis to individual pixel regions rather than uniform processing across the entire image. By examining texture characteristics in local neighborhoods and comparing them against the background model, the system can selectively identify and remove only those pixels affected by autogain while preserving legitimate foreground content with different texture properties.
2Measurement precision
If autogain is turned off to eliminate foreground-background distinction errors, then pixel distinction accuracy is improved, but image quality in low-light conditions deteriorates
Solution Approach 1:
The patent converts the harmful autogain effect into a detectable pattern by analyzing texture characteristics. Instead of eliminating autogain entirely, the system uses its characteristic texture signature to identify and remove only the affected pixels, thereby maintaining the benefits of autogain for image quality while eliminating its harmful effects on analysis accuracy.
Solution Approach 2:
The patent changes the processing parameter from binary pixel intensity values to texture-based statistical measures. By transforming the data representation and analyzing higher-order texture properties rather than raw intensity values, the system can distinguish between legitimate foreground content and autogain artifacts even when both affect pixel intensity.
3Productivity
If conventional background modeling is used without texture analysis, then processing speed is maintained, but accuracy in filtering false-positive foreground pixels deteriorates
Solution Approach 1:
The patent applies texture analysis selectively only to pixels identified as potential foreground candidates by the background model, rather than processing the entire image. This partial application of the more computationally intensive texture analysis maintains processing efficiency while achieving accurate false-positive filtering where it is most needed.
Data Source
AI summary
Techniques are disclosed for analyzing a scene depicted in an input stream of video frames captured by a video camera. Bounding boxes are determined for a set foreground patches identified in a video frame. For each bounding box, the techniques include determining textures for first areas, each including a foreground pixel and surrounding pixels, and determining textures for second areas including pixels of the background model image corresponding to the pixels of the foreground areas. Further, for each foreground pixel in the bounding box area, a correlation score is determined based on the texture of the corresponding first area and second area. Pixels whose correlation scores exceed a threshold are removed from the foreground patch. The size of the bounding box may also be reduced to fit the modified foreground patch.