Vehicle Distance Measurement Correction Using Defocus Reliability

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Solution Overview

Problem

Existing distance measurement systems in vehicles suffer from errors due to camera deformation and environmental influences, and using a separate distance measurement unit for correction requires high accuracy and may not always be suitable, leading to potential inaccuracies and reduced correction probability.

Innovation Solution

A distance measurement device that converts distance values into image plane defocus amounts, calculates a reliability score, and uses a second correction value generated within a valid time interval to enhance correction accuracy, incorporating a CPU and memory for processing and storing data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a second distance measurement unit is used to correct the distance value of the distance measurement camera, then distance measurement accuracy can be improved, but the second distance measurement unit requires higher distance accuracy and may not be suitable for all scenes

Engineering Contradiction:
Improvedistance measurement accuracyVSAvoidsuitability for various scenes
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent changes the parameter being measured from direct distance to image plane defocus amount. By converting distance measurement into a defocus amount measurement problem, the system can use the camera's existing optical system and imaging plane to obtain correction data, eliminating the need for a separate high-accuracy distance measurement unit and making the system adaptable to all scenes where the camera can capture images.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If a high reliability threshold is set for correction, then correction accuracy is improved, but the probability of correction being performed is significantly reduced

Engineering Contradiction:
Improvecorrection accuracyVSAvoidcorrection probability
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent changes the measurement parameter from distance to defocus amount, which can be reliably obtained from image data. This parameter transformation allows the system to perform corrections in a wider range of conditions because defocus amount can be accurately measured from the imaging plane without requiring additional sensors or restrictive conditions, thus increasing correction probability while maintaining accuracy.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If distance measurement is performed using a camera mounted on a vehicle, then the system can be integrated into the vehicle, but errors occur due to camera deformation and environmental influences

Engineering Contradiction:
Improvevehicle integrationVSAvoiddistance measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent uses the camera's own imaging data to generate feedback for correction. By measuring the defocus amount from the captured images and using this information to correct distance measurement errors, the system creates a self-correcting mechanism that compensates for camera deformation and environmental influences, maintaining accuracy while preserving vehicle integration.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The camera system serves itself by using its own imaging plane and captured images to generate correction data. The defocus amount measured from the camera's own images is used to correct the distance measurement errors, eliminating the need for external correction devices and enabling the system to compensate for its own deformations and environmental effects.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4632322A1Distance measurement device, movable apparatus, distance measurement method, computer program and storage medium
Publication Date: 2025.10.15 CANON KK
  • EP4632322A1 patent drawingFigure 1A~1C
  • EP4632322A1 patent drawingFigure 2A~2D
  • EP4632322A1 patent drawingFigure 3A~3C

AI summary

A distance measurement device includes: a first acquisition unit (310) configured to acquire first distance information; a second acquisition unit (320) configured to acquire second distance information; a first correction value generation unit (330) configured to calculate a first correction value for correcting the first distance information based on the second distance information; a reliability score determination unit (340) configured to calculate a reliability score indicating a reliability of the first correction value and determine the reliability of the first correction value based on the reliability score; a second correction value generation unit (350) configured to generate a second correction value from the first correction value whose reliability score is equal to or greater than a predetermined threshold and which is acquired within a predetermined valid time interval; and a correction unit (360) configured to correct the first distance information using the second correction value.