Distance Measuring Camera Using Magnification Ratio for Compact Design
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Solution Overview
Problem
Conventional distance measuring cameras face challenges in accurately calculating distances to near targets due to reduced parallel disparity and increased vignetting errors, particularly when optical systems are closely spaced, leading to reduced accuracy and larger camera sizes.
Innovation Solution
A distance measuring camera system utilizing two optical systems with different focal lengths and accounting for vignetting effects by calculating the image magnification ratio between subject images formed by these systems, even at high image heights, to accurately determine distances based on the intersection points of optical axes and principal rays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two optical systems are arranged so as to be largely spaced apart from each other in the direction perpendicular to the optical axis direction, then the parallel disparity between the distance measurement target points of the subject images increases and distance measurement accuracy is improved, but the size of the distance measuring camera increases
Solution Approach 1:
The patent changes the measurement parameter from parallel disparity to image magnification ratio. By using the ratio of magnifications of subject images formed by two optical systems with different focal lengths, the system achieves accurate distance measurement without requiring large spacing between optical systems, thus resolving the contradiction between measurement accuracy and camera size.
Solution Approach 2:
The patent replaces the mechanical approach of increasing optical system spacing with a computational approach using magnification ratio calculations. Instead of relying on physical displacement to generate measurable disparity, the system uses the optical magnification properties and mathematical computation to achieve distance measurement, eliminating the need for large physical separation.
2Volume of moving object
If two optical systems are arranged so as to be close to each other, then the camera size is reduced, but the parallel disparity between the distance measurement target points of the subject images decreases and distance measurement accuracy deteriorates
Solution Approach 1:
The patent fundamentally changes the measurement parameter from parallel disparity to image magnification ratio. This allows the system to maintain small optical system spacing while achieving accurate distance measurement through magnification ratio calculations, thereby resolving the contradiction between compact size and measurement accuracy.
3Adaptability or versatility
If the subject is located at a near distance from the distance measuring camera, then the distance measurement is needed for close-range applications, but the distance measurement target point may exist in one image data and not in the other due to visual field relationships, making parallel disparity calculation difficult
Solution Approach 1:
The patent changes from parallel disparity measurement to magnification ratio measurement. This parameter change enables near-distance measurement because magnification ratio can be accurately calculated even when the target appears in only one image or when visual fields do not overlap, resolving the contradiction between near-distance adaptability and measurement accuracy.
4Area of stationary object
If optical systems are used with high image heights, then the field of view is expanded, but vignetting errors increase and distance measurement accuracy deteriorates
Solution Approach 1:
The patent applies preliminary correction by calculating and storing the relationship between image height and magnification ratio before actual distance measurement. By pre-characterizing the vignetting effects and creating a correction map, the system compensates for vignetting errors during measurement, allowing accurate distance measurement even at high image heights with expanded field of view.
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
Enables accurate distance measurement to near targets and reduces camera size by eliminating the need for large optical system spacing, while minimizing vignetting errors through dynamic adjustment of intersection point calculations based on image heights.
Implementation Method 1
a first optical system for collecting light from the subject to form a first subject image; a second optical system for collecting the light from the subject to form a second subject image
Data Source
AI summary
A distance measurement camera contains a first optical system OS1 for forming a first subject image, a second optical system OS2 for forming a second subject image, an imaging part S for imaging the first subject image and the second subject image and a distance calculating part 4 for performing calculation depending on image heights of distance measurement target points of the first subject image and the second subject image corresponding to a distance measurement target point of a subject 100 to calculate the distance to the subject 100 based on an image magnification ratio between a magnification of the first subject image and a magnification of the first subject image and a magnification of the second subject image.