ROI Tracking Auto-Focus for Video Cameras

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Solution Overview

Problem

Existing video imaging systems face challenges in maintaining focus on moving objects during video recording due to high computational complexity and user interaction requirements, especially in scenarios with varying object location, shape, texture, and environmental changes.

Innovation Solution

A region-of-interest (ROI) tracking technique is implemented, using macroblock-based methods and color histograms to differentiate target pixels from background, allowing for automatic identification and tracking with low computational complexity, enabling robust focus control in video imaging systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional active auto-focus or passive auto-focus methods are used, then focus control is achieved, but computational complexity increases and user interaction is required

Engineering Contradiction:
Improvefocus control accuracyVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The image is divided into macroblocks, and color histograms are computed for each macroblock to differentiate target pixels from background pixels. This segmentation approach reduces computational complexity by processing smaller regions independently rather than analyzing the entire image at once.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Color histograms are computed and analyzed for specific macroblocks to identify regions with distinct color characteristics. By focusing on local color distributions rather than global image analysis, the system achieves efficient ROI identification with reduced computational load.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If traditional ROI tracking methods are used, then object tracking is achieved, but computational complexity increases

Engineering Contradiction:
Improveobject tracking accuracyVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The video frame is segmented into macroblocks, and color histograms are computed for each macroblock to identify and track ROI pixels. This segmentation enables efficient tracking by processing localized regions rather than the entire frame, reducing computational complexity while maintaining tracking accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Color histograms are used as parameters to characterize and track ROI pixels across frames. By transforming spatial information into color distribution parameters, the system achieves robust tracking with reduced computational complexity compared to traditional pixel-by-pixel analysis.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If user interaction is required for ROI identification, then identification accuracy is improved, but ease of operation decreases

Engineering Contradiction:
ImproveROI identification accuracyVSAvoiduser interaction requirement
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system automatically identifies ROIs by computing color histograms for macroblocks and detecting color differences between target and background regions. This self-service approach eliminates the need for user interaction while maintaining accurate ROI identification through automated color-based analysis.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system exploits color differences between target objects and background by computing color histograms and detecting statistical differences. This color-based approach enables automatic ROI identification without user input, improving ease of operation while maintaining identification accuracy through robust color analysis.

Inventive Principle:
Principle #32Color changes

Data Source

PatentUS8089515B2Method and device for controlling auto focusing of a video camera by tracking a region-of-interest
Publication Date: 2012.01.03 WSOU INVESTMENTS LLC
  • US8089515B2 patent drawing
  • US8089515B2 patent drawing
  • US8089515B2 patent drawing

AI summary

The invention concerns an electronic device equipped with a video imaging process capability, which device includes a camera unit arranged to produce image frames from an imaging view which includes a region-of-interest ROI, an adjustable optics arranged in connection with the camera unit in order to focus the ROI on the camera unit, an identifier unit in order to identify a ROI from the image frame, a tracking unit in order to track the ROI from the image frames during the video imaging process and an auto-focus unit arranged to analyze the ROI on the basis of the tracking results provided by the tracking unit in order to adjust the optics. The device is arranged to determine the spatial position of the ROI in the produced image frame without any estimation measures.