Monocular Camera Distance Measurement Using Bokeh Patterns

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Solution Overview

Problem

Current monocular camera systems face challenges in accurately determining distance to a subject due to environmental factors and the variability of images affected by optical aberrations, leading to reduced robustness and accuracy in distance measurement.

Innovation Solution

An image processing device that utilizes a statistical model generated by learning bokeh patterns affected by optical aberrations, performs color correction on captured images, and inputs the corrected images into the model to estimate distance, while also considering the uncertainty level and adjusting the white balance correction to improve accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If monocular camera is used to acquire distance to subject, then device complexity is reduced, but measurement precision and reliability deteriorate

Engineering Contradiction:

Improvecamera system complexityVSAvoiddistance measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent converts the harmful effect of optical aberrations (which cause bokeh) into a beneficial feature for distance measurement. By analyzing the bokeh characteristics in the captured image, the system extracts distance information that would otherwise be considered image degradation. This allows monocular cameras to achieve reliable distance measurement without requiring complex multi-camera systems.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system changes the parameter being measured from the traditional in-focus region to the out-of-focus bokeh region. By analyzing parameters such as bokeh size, shape, and intensity distribution, the system derives distance information that is not obtainable through standard sharpness-based autofocus methods in monocular systems.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If standard image processing is used without color correction, then processing speed is maintained, but measurement precision deteriorates due to environmental factors

Engineering Contradiction:

Improveprocessing speedVSAvoiddistance measurement accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preliminary color correction processing on the captured image before distance measurement. By correcting color casts caused by environmental lighting conditions (such as white balance adjustment), the system prepares the image data in advance to ensure accurate bokeh analysis. This preliminary action removes environmental variables that would otherwise degrade measurement precision.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If optical aberration effects are eliminated through lens design, then image quality is improved, but the ability to extract distance information from bokeh patterns is lost

Engineering Contradiction:

Improveimage qualityVSAvoiddistance information from bokeh

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

Rather than eliminating optical aberrations through complex lens design, the patent embraces them as the source of valuable distance information. The bokeh patterns created by spherical aberration and other optical imperfections become the primary feature for distance estimation, converting what is traditionally considered image degradation into a useful measurement signal.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enhances the accuracy and robustness of distance measurement by effectively utilizing bokeh patterns and color correction, providing reliable distance information with reduced uncertainty, even in varying environmental conditions.

Implementation Method 1

a statistical model generated by learning bokeh that occurs in a first image affected by aberration of an optical system

Methodology Applied

Scientific EffectOptical aberration:

Implementation Method 2

bokeh that occurs in a first image affected by aberration of an optical system and varies non-linearly in accordance with a distance to a subject

Methodology Applied

Scientific EffectBokeh:

Implementation Method 3

perform color correction on the second image to reduce a number of colors expressed in the second image

Methodology Applied

Scientific EffectColor correction:

Implementation Method 4

adjusting the white balance correction to improve accuracy

Methodology Applied

Scientific EffectWhite balance correction:

Data Source

PatentUS12165282B2Image processing device, ranging device, and method

Publication Date: 2024.12.10 KK TOSHIBA

AI summary

According to one embodiment, an image processing device includes storage and a processor. The storage is configured to store a statistical model generated by learning bokeh that occurs in a first image affected by aberration of an optical system and varies non-linearly in accordance with a distance to a subject in the first image. The processor is configured to acquire a second image affected by the aberration of the optical system, perform color correction on the second image to reduce a number of colors expressed in the second image, and input a third image, obtained by performing the color correction on the second image, into the statistical model and acquire first distance information indicating a distance to a subject in the third image.