Dual-Camera Gaze Estimation for Rear Camera View Alignment

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Solution Overview

Problem

Existing systems lack an effective method to control rear cameras based on accurate estimation of user gaze direction and field of view using image processing from a front camera.

Innovation Solution

A method and apparatus that utilize image processing from a front camera to estimate user gaze direction and adjust the rear camera's field of view, enabling precise control and alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If image processing from front camera is used to estimate user gaze direction, then rear camera control accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvegaze direction estimation accuracyVSAvoidimage processing system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The front camera serves multiple functions: capturing user face images for gaze estimation and capturing scene images. The same hardware component is reused for different purposes, avoiding the need for additional specialized sensors while achieving accurate gaze direction estimation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system creates a computational model of the user's gaze direction by processing facial feature positions from the front camera image. Instead of directly measuring gaze with complex eye-tracking hardware, the system copies the essential information (gaze direction) through image processing of readily available facial landmarks.

Inventive Principle:
Principle #26Copying

2Ease of operation

If multiple cameras are used for gaze estimation and field of view alignment, then control precision is improved, but device complexity increases

Engineering Contradiction:
Improvecamera control precisionVSAvoidmulti-camera system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The system merges the functional roles of multiple cameras into a coordinated system where the front camera captures facial information for gaze estimation and the rear camera captures the target scene. By combining these functions and processing their data together, the system achieves precise camera control without requiring each camera to be independently complex.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The front camera acts as an intermediary that provides gaze direction information to control the rear camera. Instead of directly complexifying the rear camera control system, the patent introduces the front camera as a mediating component that translates user intent into camera control parameters.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Speed

If real-time image processing is performed, then responsiveness is improved, but energy consumption increases

Engineering Contradiction:
Improvegaze estimation responsivenessVSAvoidimage processing energy consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The system extracts only the essential information needed for gaze estimation from the front camera image, specifically the positions of facial landmarks (eyes, eyebrows, nose). Instead of processing the entire image data, the patent selectively extracts relevant features, reducing computational load and energy consumption while maintaining real-time responsiveness.

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If accurate gaze direction estimation is implemented, then user experience is improved, but processing time increases

Engineering Contradiction:
Improvegaze direction accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary detection of facial landmarks and prepares the gaze estimation model in advance. By pre-processing and pre-positioning the computational framework, the patent reduces the time required for actual gaze calculation when the user looks at the screen, achieving both accuracy and speed.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4250738B1Method for controlling a camera based on processing an image captured by other camera
Publication Date: 2025.12.31 SNAP AID PATENTS LTD
  • EP4250738B1 patent drawingFigure 1
  • EP4250738B1 patent drawingFigure 2
  • EP4250738B1 patent drawingFigure 3

AI summary

A device comprises a first digital camera having a first center line of sight and a second digital camera having a second center line of sight that is parallel and opposing the first camera. A method for controlling the first camera based on estimating the angular deviation between a person gaze direction and the line of sight of the first digital camera. A Human face is detected in an image captured as an image file by the second digital camera, using a face detection algorithm. An angular deviation α is estimated, defined between the second center line of sight and an imaginary line from the second camera to the detected human face based on the captured image, and an angular deviation β is estimated, defined between the imaginary line from the second camera to the detected face and the human face gaze direction based on the captured image.