Camera Self-Calibration via Hybrid Deep Learning and Geometric Optimization

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Solution Overview

Problem

Existing self-calibration methods for cameras, especially in safety-critical applications like automated driving, are not precise enough and require extensive computational resources, making them impractical for regular recalibration due to temperature changes and mechanical influences.

Innovation Solution

A hybrid method combining deep learning for feature extraction and correspondence searching with classic geometric optimization, allowing for the estimation of camera parameters from any image sequence, enabling online calibration and detection of parameter drifts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If classic calibration procedures are used, then measurement precision is improved, but device complexity and ease of operation deteriorate due to complex procedures requiring special equipment and expert operation

Engineering Contradiction:
Improvecamera parameter precisionVSAvoidcalibration procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs self-calibration automatically using images captured during normal operation. The calibration procedure executes itself without requiring external calibration equipment or expert intervention, transforming the calibration process from a manual expert task into an automated self-service operation that occurs in the background during regular camera use.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention extracts the calibration functionality from the complex traditional calibration procedure and special calibration equipment. By using only images captured during normal operation and performing correspondence searching and optimization algorithmically, the system removes the need for dedicated calibration devices and complex manual procedures, achieving calibration through extracted image data alone.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If deep learning methods are used for self-calibration, then ease of operation is improved, but measurement precision deteriorates due to dependence on training data and insufficient precision for safety-critical applications

Engineering Contradiction:
Improveautomatic calibration capabilityVSAvoidcamera parameter precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system merges the automatic operation capability of deep learning methods with the high precision of classic geometric optimization. The workflow combines automated feature extraction and correspondence searching (providing ease of operation) with precise optimization algorithms that refine camera parameters (ensuring measurement precision), achieving both automatic operation and high precision suitable for safety-critical applications.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention uses ascertained correspondences as an intermediary between the automated deep learning stage and the precision optimization stage. The correspondences extracted automatically serve as input for the optimization algorithm, bridging the gap between automated operation and precise parameter determination, enabling the system to achieve both ease of operation and measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If existing self-calibration algorithms are used, then device complexity is reduced, but measurement precision deteriorates due to insufficient precision and environmental requirements

Engineering Contradiction:
Improvecalibration procedure simplicityVSAvoidcamera parameter precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The system dynamically adapts the calibration process by iteratively refining correspondences and re-optimizing parameters. Rather than using a static single-pass algorithm, the system performs multiple optimization iterations with updated correspondences, allowing the calibration process to dynamically improve precision while maintaining relative simplicity through automated execution.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention enables continuous calibration by performing optimization algorithms repeatedly with updated correspondences throughout the camera's operation. This continuous refinement of parameters maintains high precision without requiring complex interruptive calibration procedures, achieving both simplicity and precision through ongoing automated calibration actions.

Inventive Principle:
Principle #20Continuity of useful action

4Ease of operation

If video-based self-calibration methods are used, then ease of operation is improved, but loss of time increases due to computational intensity requiring over 12 hours for training

Engineering Contradiction:
Improveautomatic calibration capabilityVSAvoidcomputational time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The system performs preliminary feature extraction and correspondence searching using automated algorithms before the optimization stage. By preparing correspondences in advance during normal operation and storing them for later use, the system reduces the computational burden during actual calibration, enabling fast execution of the optimization algorithms without requiring extensive training time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention replaces computationally intensive deep learning training with more efficient optimization algorithms that operate on pre-extracted correspondences. By substituting the mechanical training process with algebraic optimization methods that work on prepared data, the system achieves automatic calibration with dramatically reduced computational time, making real-time calibration practical.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS20240070917A1Method for self-calibration of at least one camera
Publication Date: 2024.02.29 ROBERT BOSCH GMBH
  • US20240070917A1 patent drawing
  • US20240070917A1 patent drawing
  • US20240070917A1 patent drawing

AI summary

A computer-implemented method for self-calibration of at least one camera. The method comprises: ascertaining at least two corresponding images from a sequence of recorded images, the recorded images resulting from recordings of the camera, the corresponding images having correspondences which are specific to at least one camera parameter, the camera parameter being specific to the geometric imaging behavior of the camera; ascertaining the respective correspondence by an application of an artificial neural network, the application being based on the corresponding images; determining at least the camera parameter based on the ascertained correspondences for the self-calibration of the camera.