Optical three-dimensional measurements by radially symmetric structured light projection

Single circular targets are widely used as calibration objects during line-structured light three-dimensional (3D) measurements because they are versatile and easy to manufacture. This paper proposes a new calibration method for line-structured light 3D measurements based on a single circular target. First, the target is placed in several positions and illuminated by a light beam emitted from a laser projector. A camera captures the resulting images and extracts an elliptic fitting profile of the target and the laser stripe. Second, an elliptical cone equation defined by the elliptic fitting profile and optical center of the camera is established based on the projective geometry. By combining the obtained elliptical cone and the known diameter of the circular target, two possible positions and orientations of the circular target are determined and two groups of 3D intersection points between the light plane and the circular target are identified. Finally, the correct group of 3D intersection points is filtered and the light plane is progressively fitted. The accuracy and effectiveness of the proposed method are verified both theoretically and experimentally. The obtained results indicate that a calibration accuracy of 0.05 mm can be achieved for an 80 mm × 80 mm planar target.

Download Full-text

Three-dimensional measurements in gas flows

International Congress on Applications of Lasers & Electro-Optics ◽

10.2351/1.5057805 ◽

1986 ◽

Author(s):

Brandon Yip ◽

Marshall B. Long

Keyword(s):

Three Dimensional ◽

Gas Flows ◽

Dimensional Measurements

Download Full-text

Structured-light 3D scanning of exhibited historical clothing—a first-ever methodical trial and its results

Heritage Science ◽

10.1186/s40494-021-00544-x ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Jerzy Montusiewicz ◽

Marek Miłosz ◽

Jacek Kęsik ◽

Kamil Żyła

Keyword(s):

Cultural Heritage ◽

Information Technologies ◽

Structured Light ◽

Three Dimensional ◽

3D Models ◽

3D Scanning ◽

Dimensional Representation ◽

3D Scanner ◽

Three Dimensional Representation ◽

3D Scanners

AbstractHistorical costumes are part of cultural heritage. Unlike architectural monuments, they are very fragile, which exacerbates the problems of their protection and popularisation. A big help in this can be the digitisation of their appearance, preferably using modern techniques of three-dimensional representation (3D). The article presents the results of the search for examples and methodologies of implementing 3D scanning of exhibited historical clothes as well as the attendant problems. From a review of scientific literature it turns out that so far practically no one in the world has made any methodical attempts at scanning historical clothes using structured-light 3D scanners (SLS) and developing an appropriate methodology. The vast majority of methods for creating 3D models of clothes used photogrammetry and 3D modelling software. Therefore, an innovative approach was proposed to the problem of creating 3D models of exhibited historical clothes through their digitalisation by means of a 3D scanner using structural light technology. A proposal for the methodology of this process and concrete examples of its implementation and results are presented. The problems related to the scanning of 3D historical clothes are also described, as well as a proposal how to solve them or minimise their impact. The implementation of the methodology is presented on the example of scanning elements of the Emir of Bukhara's costume (Uzbekistan) from the end of the nineteenth century, consisting of the gown, turban and shoes. Moreover, the way of using 3D models and information technologies to popularise cultural heritage in the space of digital resources is also discussed.

Download Full-text

Combining 3D Structured Light Imaging and Spine X-ray Data Improves Visualization of the Spinous Lines in the Scoliotic Spine

Applied Sciences ◽

10.3390/app11010301 ◽

2020 ◽

Vol 11 (1) ◽

pp. 301

Author(s):

Sławomir Paśko ◽

Wojciech Glinkowski

Keyword(s):

Radiation Exposure ◽

Surface Topography ◽

Structured Light ◽

Spinous Process ◽

Three Dimensional ◽

Diagnostic System ◽

Measurement Tool ◽

Adequate Treatment ◽

X Ray ◽

Spinous Processes

Scoliosis is a three-dimensional trunk and spinal deformity. Patient evaluation is essential for the decision-making process and determines the selection of specific and adequate treatment. The diagnosis requires a radiological evaluation that exposes patients to radiation. This exposure reaches hazardous levels when numerous, repetitive radiographic studies are required for diagnostics, monitoring, and treatment. Technological improvements in radiographic devices have significantly reduced radiation exposure, but the risk for patients remains. Optical three-dimensional surface topography (3D ST) measurement systems that use surface topography (ST) to screen, diagnose, and monitor scoliosis are safer alternatives to radiography. The study aimed to show that the combination of plain X-ray and 3D ST scans allows for an approximate presentation of the vertebral column spinous processes line in space to determine the shape of the spine’s deformity in scoliosis patients. Twelve patients diagnosed with scoliosis, aged 13.1 ± 4.5 years (range: 9 to 20 years) (mean: Cobb angle 17.8°, SD: ±9.5°) were enrolled in the study. Patients were diagnosed using full-spine X-ray and whole torso 3D ST. The novel three-dimensional assessment of the spinous process lines by merging 3D ST and X-ray data in patients with scoliosis was implemented. The method’s expected uncertainty is less than 5 mm, which is better than the norm for a standard measurement tool. The presented accuracy level is considered adequate; the proposed solution is accurate enough to monitor the changes in the shape of scoliosis’s spinous processes line. The proposed method allows for a relatively precise calculation of the spinous process lines based on a three-dimensional point cloud obtained with a four-directional, three-dimensional structured light diagnostic system and a single X-ray image. The method may help reduce patients’ total radiation exposure and avoid one X-ray in the sagittal projection if biplanar radiograms are required for reconstructing the three-dimensional line of the spinous processes line.

Download Full-text

Three-dimensional surface reconstruction within noncontact diffuse optical tomography using structured light

Journal of Biomedical Optics ◽

10.1117/1.jbo.17.12.126009 ◽

2012 ◽

Vol 17 (12) ◽

pp. 126009 ◽

Cited By ~ 2

Author(s):

Kirstin Baum ◽

Raimo Hartmann ◽

Tobias Bischoff ◽

Jan O. Oelerich ◽

Stephan Finkensieper ◽

...

Keyword(s):

Surface Reconstruction ◽

Structured Light ◽

Optical Tomography ◽

Three Dimensional ◽

Diffuse Optical Tomography ◽

Dimensional Surface

Download Full-text

Atomic force microscope cantilever based microcoordinate measuring probe for true three-dimensional measurements of microstructures

Applied Physics Letters ◽

10.1063/1.2786881 ◽

2007 ◽

Vol 91 (12) ◽

pp. 121912 ◽

Cited By ~ 15

Author(s):

Gaoliang Dai ◽

Helmut Wolff ◽

Hans-Ulrich Danzebrink

Keyword(s):

Atomic Force Microscope ◽

Three Dimensional ◽

Atomic Force Microscope Cantilever ◽

Atomic Force ◽

Measuring Probe ◽

Dimensional Measurements ◽

Force Microscope Cantilever

Download Full-text

IMG-07. GADOLINIUM IS NOT NECESSARY FOR SURVEILLANCE MR IMAGING IN CHILDREN WITH CHIASMATIC-HYPOTHALAMIC LOW GRADE GLIOMA

Neuro-Oncology ◽

10.1093/neuonc/noaa222.343 ◽

2020 ◽

Vol 22 (Supplement_3) ◽

pp. iii356-iii356

Author(s):

Fatema Malbari ◽

Murali Chintagumpala ◽

Jack Su ◽

Mehmet Okcu ◽

Frank Lin ◽

...

Keyword(s):

Metastatic Disease ◽

Three Dimensional ◽

Low Grade Glioma ◽

Cancer Center ◽

Low Grade ◽

Contrast Imaging ◽

Post Contrast ◽

Best Response ◽

Dimensional Measurements ◽

Initiation Of Therapy

Abstract BACKGROUND Patients with chiasmatic-hypothalamic low grade glioma (CHLGG) have frequent MRIs with gadolinium based contrast agents (GBCA) for disease monitoring. Cumulative gadolinium deposition in children is a potential concern. The purpose of this research is to establish whether MRI with GBCA is necessary for determining tumor progression in children with CHLGG. METHODS Children with progressive CHLGG were identified from Texas Children’s Cancer Center between 2005–2019. Pre- and post-contrast MRI sequences were separately reviewed by one neuroradiologist who was blinded to the clinical course. Three dimensional measurements and tumor characteristics were collected. Radiographic progression was defined as a 25% increase in size (product of two largest dimensions) compared to baseline or best response after initiation of therapy. RESULTS A total of 28 patients with progressive CHLGG including 683 MRIs with GBCA (mean 24 MRIs/patient; range: 10–43 MRIs) were reviewed. No patients had a diagnosis of NF1. Progression was observed 92 times, 91 (98.9%) on noncontrast and 90 (97.8%) on contrast imaging. Sixty-seven radiographic and/or clinical progressions necessitating management changes were identified in all (100%) noncontrast sequences and 66 (98.5%) contrast sequences. Tumor growth >2 mm in any dimension was identified in 184/187(98.4%) on noncontrast and 181/187(96.8%) with contrast imaging. Non primary metastatic disease was seen in seven patients (25%), which were better visualized on contrast imaging in 4 (57%). CONCLUSION MRI without GBCA effectively identifies patients with progressive disease. One should consider eliminating contrast in imaging of children with CHLGG with GBCA reserved for monitoring those with metastatic disease.

Download Full-text