On the Design, Construction and Operation of a Diffraction Rangefinder MS Thesis Presentation Gino Lopes A Thesis submitted to the Graduate Faculty of Fairfield University in partial fulfillment of the requirements for the degree of a Master of Science in the Electrical and Computer Engineering.
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On the Design, Construction and Operation of a Diffraction Rangefinder MS Thesis Presentation Gino Lopes A Thesis submitted to the Graduate Faculty of.
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On the Design, Construction and Operation of a Diffraction
Rangefinder
MS Thesis Presentation
Gino LopesA Thesis submitted to the Graduate Faculty of Fairfield University
in partial fulfillment of the requirements for the degree of a Master of Science in the Electrical and Computer Engineering.
Outline
• Problem• Approach• Motivation• Rangefinding• Design and Testing• Performance and Comparison• Conclusion• Future Work
Problem
• Design a diffraction rangefinder, subject to the following constraints:– Fit on a desktop, – Digitize and display objects,– Be affordable,– Be easy to use,– Not suffer from occlusion issues, characteristic of
triangulation rangefinders,– Characterize the performance of the rangefinder
Approach
• Design a Prototype for testing.– Hardware• Diffraction grating.• Network Camera instead of USB camera.• Laser line generator.• Motion control hardware.
– Software• JAVA was used for everything.
– Layout of 3D Scanner• Dependent on hardware parameters.
Motivation
• Diffraction rangefinders represent a new class of rangefinder for digitizing object.
• Verify predicted performance.
Rangefinding
• Types of Rangefinders:– Shape to shading:• Process of computing the shape of a three-dimensional
surface by looking at the brightness of one image of the surface.• Shape to shading is difficult to implement.
Rangefinding Continued
– Triangulation:• Finds the range-to-target by using two different views
(angles) of the target, or by making use of off-access illumination. • Transmitter and receiver are separated.• Subject to shadows.
Rangefinding Continued
– Light Detection and Ranging (LIDAR) system:• Uses laser pulse time of flight.• Receiver and transmitter can be co-axial and shadows
and occlusion limitation are minimized.• For surface scanning the laser source or target would
need to be moved in both the x-axis and y-axis.– To collect enough data points to reproduce the surface detail.
Rangefinding Continued
– Diffraction Rangefinders:• Measures the distance to a target by reading the
curvature of the wave front.• Work with (active illumination) using a laser.• Less susceptibility to occlusion.• Receiver and transmitter can be co-axial.• Limitation in range of measurement due to size of the
grating.
Design
• Scanner Design:– Illumination Source:• Off the shelf red laser line generator