Image Generation Device Distance Measurement with Pattern Light
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Solution Overview
Problem
Conventional image generation devices struggle with accurately determining distance to objects due to light dots being lost or erroneously detected, especially at far distances, leading to recognition issues of quadrangle patterns and incorrect pattern identification.
Innovation Solution
An image generation device that projects a pattern of light dots with specific arrangements, allowing for the separation of background and projection components, and uses pre-stored relationships between light dot positions and projection angles to calculate distances, even when light dots are lost or incorrectly detected, by maintaining a fixed number of illuminated dots within unit patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light projector projects pattern light using a diffraction grating and laser light, then the distance between light dots increases in proportion to the distance to the object, but the size of the projected light dot does not change, causing light dots to be lost or erroneously detected at far distances
Solution Approach 1:
The patent applies different illumination states (illuminated vs. non-illuminated) to different light dots in the projection pattern, creating distinguishable states that can be reliably detected. By assigning specific illumination patterns to different spatial positions, the system can identify light dots even when their size becomes small at far distances, thus maintaining detection reliability while preserving distance measurement accuracy.
2Measurement precision
If pattern matching computation is performed between captured image and reference images to calculate correlation values, then distance information can be acquired, but the computation amount becomes large
Solution Approach 1:
The patent segments the projection pattern into multiple unit patterns arranged in rows and columns, where each unit pattern contains a specific arrangement of illuminated and non-illuminated light dots. This segmentation allows the system to identify distance information by analyzing the arrangement pattern rather than performing full-image correlation matching, significantly reducing computation amount while maintaining distance measurement accuracy.
Solution Approach 2:
The patent changes the approach from correlation-based distance calculation to a method based on analyzing the arrangement parameters of illuminated light dots. By counting and positioning the illuminated dots within unit patterns and comparing their arrangement to reference patterns, the system can determine distance with much lower computational requirements than traditional correlation matching.
3Device complexity
If quadrangle patterns with four linked light dots are used for distance measurement, then computation can be simplified, but light spots cannot be reliably recognized when light dots are lost or erroneously detected
Solution Approach 1:
The patent preliminarily defines specific illumination patterns for different spatial positions in the projection pattern. Before distance measurement, the system establishes a reference arrangement of illuminated and non-illuminated light dots for each unit pattern. During measurement, the system compares the captured pattern against these pre-defined arrangements, enabling reliable recognition even when some light dots are lost or erroneously detected, thus maintaining both simplicity and reliability.
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
This approach enables accurate distance information acquisition even at far distances, reduces computational complexity, and enhances pattern recognition without requiring distinct pattern boundary identification codes, while simplifying the diffraction grating structure and increasing light strength.
Implementation Method 1
an imaging unit (11) that generates an imaging signal by capturing an image of an imaging space
Implementation Method 2
a projection unit (22) that forms a projection pattern as a projection image on an object that exists in the imaging space, by projecting pattern light toward the imaging space
Data Source
AI summary
An image generation device includes an imaging unit 11, a projection unit 22, and a distance information generation unit 18, and a projection pattern includes unit patterns arranged in a plurality of rows in a first direction and in a plurality of columns in a second direction. A plurality of light dots include first dots and second dots which are light dots of different states from each other; the unit patterns arranged in the first direction have the light dot arrangements identical with each other; the unit patterns arranged in the second direction have light dot arrangements different from each other; the number of first dots among a plurality of light dots arranged in the first direction in each of the unit patterns is the same fixed number in each row in the second direction; and in a location other than the unit pattern, the number of first dots included in a row of the same length as the unit pattern in the second direction differs from the fixed number, in a certain row in the second direction.