Single-Shot, Monochrome, Spatial Pixel-Encoded, Structured Light System for Determining Surface Orientations

This study introduces a technique for determining surface orientations by projecting a monochrome, spatial pixel-encoded pattern and calculating the surface normals from single-shot measurement. Our method differs from traditional methods, such as shape from shading and shape from texture, in that i...

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Main Authors: Ahsan Elahi, Qidan Zhu, Jun Lu, Umer Farooq, Ghulam Farid, Muhammad Bilal, Yong Li
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Photonics
Subjects:
Online Access:https://www.mdpi.com/2304-6732/11/11/1046
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author Ahsan Elahi
Qidan Zhu
Jun Lu
Umer Farooq
Ghulam Farid
Muhammad Bilal
Yong Li
author_facet Ahsan Elahi
Qidan Zhu
Jun Lu
Umer Farooq
Ghulam Farid
Muhammad Bilal
Yong Li
author_sort Ahsan Elahi
collection DOAJ
description This study introduces a technique for determining surface orientations by projecting a monochrome, spatial pixel-encoded pattern and calculating the surface normals from single-shot measurement. Our method differs from traditional methods, such as shape from shading and shape from texture, in that it does not require relating the local surface orientations of adjacent points. We propose a multi-resolution system incorporating symbols varying in sizes from 8 × 8, 10 × 10, 12 × 12, 14 × 14, and 16 × 16 pixels. Compared to previous methods, we have achieved a denser reconstruction and obtained a 5.2 mm resolution using an 8 × 8 pattern at a depth of 110 cm. Unlike previous methods, which used local point orientations of grid intersection and multiple colors, we have used the monochrome pattern and deterministic centroid positions to compute the unit vector or direction vector between the neighboring symbols. The light plane intersections are used to calculate the tangent vectors on the surface. Surface normals are determined by the cross-product of two tangent vectors on the surface. A real experiment was conducted to measure simple plane surfaces, circular surfaces, and complex sculptures. The results show that the process of calculating surface normals is fast and reliable, and we have computed 1654 surface normals in 29.4 milliseconds for complex surfaces such as sculptures.
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spelling doaj-art-fdf6672b4e48431794e23d33fe014fa92025-08-20T02:27:35ZengMDPI AGPhotonics2304-67322024-11-011111104610.3390/photonics11111046Single-Shot, Monochrome, Spatial Pixel-Encoded, Structured Light System for Determining Surface OrientationsAhsan Elahi0Qidan Zhu1Jun Lu2Umer Farooq3Ghulam Farid4Muhammad Bilal5Yong Li6College of Intelligent Systems, Science and Engineering, Harbin Engineering University, Harbin 150001, ChinaCollege of Intelligent Systems, Science and Engineering, Harbin Engineering University, Harbin 150001, ChinaCollege of Intelligent Systems, Science and Engineering, Harbin Engineering University, Harbin 150001, ChinaCollege of Mathematical Sciences, Harbin Engineering University, Harbin 150001, ChinaCollege of Intelligent Systems, Science and Engineering, Harbin Engineering University, Harbin 150001, ChinaCollege of Intelligent Systems, Science and Engineering, Harbin Engineering University, Harbin 150001, ChinaCollege of Intelligent Systems, Science and Engineering, Harbin Engineering University, Harbin 150001, ChinaThis study introduces a technique for determining surface orientations by projecting a monochrome, spatial pixel-encoded pattern and calculating the surface normals from single-shot measurement. Our method differs from traditional methods, such as shape from shading and shape from texture, in that it does not require relating the local surface orientations of adjacent points. We propose a multi-resolution system incorporating symbols varying in sizes from 8 × 8, 10 × 10, 12 × 12, 14 × 14, and 16 × 16 pixels. Compared to previous methods, we have achieved a denser reconstruction and obtained a 5.2 mm resolution using an 8 × 8 pattern at a depth of 110 cm. Unlike previous methods, which used local point orientations of grid intersection and multiple colors, we have used the monochrome pattern and deterministic centroid positions to compute the unit vector or direction vector between the neighboring symbols. The light plane intersections are used to calculate the tangent vectors on the surface. Surface normals are determined by the cross-product of two tangent vectors on the surface. A real experiment was conducted to measure simple plane surfaces, circular surfaces, and complex sculptures. The results show that the process of calculating surface normals is fast and reliable, and we have computed 1654 surface normals in 29.4 milliseconds for complex surfaces such as sculptures.https://www.mdpi.com/2304-6732/11/11/10463D measurementM-arrayspixel-encodedrobust pseudo-random sequenceplanar intersectionsingle-shot
spellingShingle Ahsan Elahi
Qidan Zhu
Jun Lu
Umer Farooq
Ghulam Farid
Muhammad Bilal
Yong Li
Single-Shot, Monochrome, Spatial Pixel-Encoded, Structured Light System for Determining Surface Orientations
Photonics
3D measurement
M-arrays
pixel-encoded
robust pseudo-random sequence
planar intersection
single-shot
title Single-Shot, Monochrome, Spatial Pixel-Encoded, Structured Light System for Determining Surface Orientations
title_full Single-Shot, Monochrome, Spatial Pixel-Encoded, Structured Light System for Determining Surface Orientations
title_fullStr Single-Shot, Monochrome, Spatial Pixel-Encoded, Structured Light System for Determining Surface Orientations
title_full_unstemmed Single-Shot, Monochrome, Spatial Pixel-Encoded, Structured Light System for Determining Surface Orientations
title_short Single-Shot, Monochrome, Spatial Pixel-Encoded, Structured Light System for Determining Surface Orientations
title_sort single shot monochrome spatial pixel encoded structured light system for determining surface orientations
topic 3D measurement
M-arrays
pixel-encoded
robust pseudo-random sequence
planar intersection
single-shot
url https://www.mdpi.com/2304-6732/11/11/1046
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