Distorted Camera Image Correction for Optical Flow

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Solution Overview

Problem

The existing methods for calculating optical flow from images in a sequence, especially in autonomous vehicles, face challenges when images are distorted, leading to unreliable flow calculations.

Innovation Solution

An image processing method that involves obtaining two images, detecting distortions, determining a warping function to compensate for distortions, applying this function to the images, and calculating the optical flow as a displacement vector field, which can include using multiple warping functions and combining results for improved accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If optical flow is calculated from distorted images, then processing can be performed on raw camera data, but the accuracy of optical flow estimation deteriorates

Engineering Contradiction:
Improveoptical flow calculation capabilityVSAvoidoptical flow estimation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by warping the distorted image before calculating optical flow. The warping function is applied in advance to correct lens distortion and camera motion effects, transforming the distorted image into a corrected version that can be processed by standard optical flow algorithms. This preliminary correction ensures that the optical flow calculation operates on geometrically accurate data, resolving the contradiction between processing raw data and maintaining accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses an intermediary approach by introducing a warping function as a mediator between the distorted camera image and the optical flow calculation. This warping function acts as a transformation layer that converts the distorted image into a corrected representation, allowing the optical flow algorithm to operate on geometrically accurate data without directly processing the raw distorted images, thus maintaining both processing capability and accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If warping function is applied to correct distortion, then optical flow accuracy is improved, but image processing complexity increases

Engineering Contradiction:
Improveoptical flow estimation accuracyVSAvoidimage processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by using a warping function that transforms image coordinates based on distortion models. The warping function modifies the spatial parameters of the image by applying correction factors derived from camera calibration and motion estimation. This parameter transformation corrects geometric distortions while maintaining a manageable processing complexity through efficient mathematical operations.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If multiple warping functions are used to compensate for different distortions, then correction accuracy is improved, but computational requirements increase

Engineering Contradiction:
Improvedistortion compensation accuracyVSAvoidcomputational energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies segmentation by dividing the distortion compensation into separate functional components: lens distortion correction and camera motion correction. Each component has its own dedicated warping function that handles a specific type of distortion. This segmentation allows the system to apply multiple correction functions in a structured manner, improving overall accuracy while managing computational requirements through modular processing.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS9330472B2System and method for distorted camera image correction
Publication Date: 2016.05.03 HONDA MOTOR CO LTD
  • US9330472B2 patent drawing
  • US9330472B2 patent drawing
  • US9330472B2 patent drawing

AI summary

The invention provides an image processing method for processing a sequence of images, comprising the steps of: obtaining, from a visual sensor, at least two images of the sequence of images, detecting whether the images include a distortion, determining an image warping function at least partially compensating the distortion, applying the determined warping function to the image(s) including the distortion, and calculating by a processing unit, and outputting, an optical flow as a displacement vector field form the images.