Mobile Video Background Modification Using CRF Segmentation

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Solution Overview

Problem

Mobile devices face challenges in processing video data due to limited processing power and battery constraints, particularly in handling camera motion, subject motion, and illumination changes, which affects the ability to modify video backgrounds effectively for applications like video calls.

Innovation Solution

Implementing a method on mobile devices for real-time background/foreground separation using Conditional Random Fields (CRFs) and user input, allowing for hiding, replacing, or blurring background regions, and combining this with face detection to enhance video communication experiences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If real-time background/foreground separation is implemented using CRFs and image processing techniques, then video modification accuracy and user experience are improved, but processing power consumption and battery drain increase

Engineering Contradiction:
Improvevideo modification accuracyVSAvoidprocessing power consumption
Core Design Contradiction:
Manufacturing precisionVSPower

Solution Approach 1:

The video processing is divided into discrete segments: face detection, background/foreground separation using CRFs, and region-specific modification. This segmentation allows the system to process only relevant portions of the video frame by frame, reducing overall computational load while maintaining accuracy in critical regions like faces and backgrounds.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different processing quality levels are applied to different regions of the video. High-accuracy CRF-based segmentation is applied to background regions requiring modification, while simpler processing is applied to foreground regions (faces) that need preservation. This local differentiation optimizes the balance between processing accuracy and power consumption.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If real-time video processing is performed on mobile devices, then video modification capability is improved, but battery life is reduced

Engineering Contradiction:
Improvevideo modification capabilityVSAvoidbattery life
Core Design Contradiction:
Adaptability or versatilityVSDuration of action of stationary object

Solution Approach 1:

The system processes video frames periodically rather than continuously at full resolution. Background/foreground separation is performed on key frames or at reduced frame rates, with interpolation used between processed frames. This periodic processing maintains video modification capability while significantly reducing cumulative power consumption and extending battery life.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system applies partial processing to the most critical regions (backgrounds requiring replacement or blurring) while using simpler or no processing for less critical areas. This partial action approach provides sufficient video modification capability for typical use cases while minimizing unnecessary power consumption that would drain the battery.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If camera motion and subject motion are handled in real-time, then video quality is improved, but processing complexity increases

Engineering Contradiction:
Improvevideo qualityVSAvoidprocessing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Motion detection and compensation are performed preliminarily on detected face regions and background segments before applying the CRF-based background/foreground separation. This preliminary motion analysis allows the system to prepare transformation parameters in advance, reducing the complexity of real-time processing while maintaining video quality during camera and subject motion.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

An intermediary motion estimation module bridges the camera/subject motion detection and the background modification processes. This intermediary layer processes motion information separately from the CRF segmentation, allowing each component to optimize its own complexity while working together to maintain video quality during dynamic conditions.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Loss of energy

If background regions are replaced or blurred, then privacy protection and bandwidth efficiency are improved, but processing time increases

Engineering Contradiction:
Improvebandwidth usageVSAvoidprocessing time
Core Design Contradiction:
Loss of energyVSLoss of time

Solution Approach 1:

The system extracts and processes only the background regions that require modification (replacement or blurring) separately from the foreground content. By taking out and processing only the necessary background portions using CRF-based segmentation, the system reduces overall processing time compared to processing the entire video frame, while still achieving the desired privacy protection and bandwidth efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS9153031B2Modifying video regions using mobile device input
Publication Date: 2015.10.06 MICROSOFT TECHNOLOGY LICENSING LLC
  • US9153031B2 patent drawing
  • US9153031B2 patent drawing
  • US9153031B2 patent drawing

AI summary

Apparatus and methods are disclosed for modifying video based on user input and or face detection data received with a mobile device to generate foreground regions (e.g., to separate a user image from background in the video). According to one disclosed embodiment, a method comprises receiving user input and/or face regions generated with a mobile device, producing an initial representation for segmenting input video into a plurality of portions based on the user input, where the initial representation includes probabilities for one or more regions of the input video being designated as foreground regions or background regions. Based on the initial representation, input video is segmented by designating one or more of the regions of the input video as foreground regions or background regions.