Dynamic Video Frame Cropping for Bandwidth-Constrained Stabilization

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Solution Overview

Problem

Wearable camera systems face challenges in stabilizing images due to extreme camera movements associated with user body activities, requiring more robust digital image stabilization methods that can efficiently handle high-resolution video frames while minimizing bandwidth and processing costs.

Innovation Solution

The method involves using a high-resolution camera sensor that dynamically crops video frames before digital image stabilization, employing two-phase cropping: an initial crop at the camera module and a secondary crop at the host apparatus, to reduce the resolution and bandwidth, while maintaining sufficient image quality for stabilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high-resolution video frames are processed for digital image stabilization, then image quality is improved, but bandwidth and processing costs increase

Engineering Contradiction:
Improveimage qualityVSAvoidbandwidth
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent divides the video frame processing into two distinct cropping stages: a first crop that reduces the frame to a smaller resolution, and a second crop that further processes the already-reduced frame. This segmentation allows the system to maintain image quality for stabilization while significantly reducing the total data volume that requires bandwidth transmission and processing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs the first crop as a preliminary action before digital image stabilization processing. By pre-reducing the resolution of video frames through this initial cropping step, the system prepares the data in a more efficient format that requires less bandwidth and processing power for the subsequent stabilization operations, while still preserving sufficient image quality.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If high-resolution video frames are processed for digital image stabilization, then image quality is improved, but processing costs increase

Engineering Contradiction:
Improveimage qualityVSAvoidprocessing costs
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the processing workflow into two distinct cropping operations rather than performing one complex high-resolution processing operation. This segmentation reduces processing costs by breaking down the computational burden into manageable stages that can be executed more efficiently.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first crop serves as a preliminary processing step that reduces the resolution before the main digital image stabilization processing occurs. This preliminary action significantly reduces the computational complexity and processing costs of the subsequent stabilization operations, as the algorithm operates on smaller, more manageable data sets while still achieving the desired stabilization effect.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If high-resolution video frames are processed for digital image stabilization, then image quality is improved, but energy consumption increases

Engineering Contradiction:
Improveimage qualityVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The first crop is performed as a preliminary action that reduces the resolution of video frames before they undergo digital image stabilization processing. This preliminary resolution reduction significantly decreases the computational workload and associated energy consumption for the subsequent stabilization operations, while still maintaining sufficient image quality for effective stabilization.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the processing into two cropping stages, which divides the energy-intensive processing task into smaller, more energy-efficient steps. This segmentation allows the system to achieve the same stabilization quality with lower overall energy consumption compared to processing full-resolution frames through a single complex stabilization algorithm.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2815569B1Video image stabilization
Publication Date: 2021.11.10 NOKIA TECHNOLOGIES OY
  • EP2815569B1 patent drawingFigure 1~3
  • EP2815569B1 patent drawingFigure 4~5
  • EP2815569B1 patent drawingFigure 6

AI summary

A method comprising: receiving cropping information for a current video frame; capturing at a camera sensor the current video frame; performing a first crop of the current video frame using a first cropping window to form a cropped video frame, wherein the first cropping window has been dynamically adjusted in response to the received cropping information; and sending the cropped video frame for digital image stabilization.