EXPERIMENTAL STUDY OF LOW COST 3D SCANNER ,

COMPARITIVE ANALYSIS WITH COMMERCIAL SCANNNER

THESIS SYNOPSIS
SUBMITTED IN PARTIAL FULLFILLMENT OF THE REQUIREMENT FOR
THE DEGREE OF

Master of Technology
(Mechanical Engineering)
SUBMITTED BY

ROHIT GUPTA
Roll No. : 1453695

SRI SAI COLLEGE OF ENGINEERING AND TECHNOLOGY, BADHANI

PUNJAB TECHNICAL UNIVERSITY

SUBMITTED TO:
Asst.Prof. Himanshu Chaudhary

CONTENTS

TITLE
CHAPTER 1
INTRODUCTION3 4

CHAPTER 2
LITERATURE REVIEW.....5 - 6

CHAPTER 3
PROBLEM FORMULATION ..7

REFERENCES...8

Chapter1
2

INTRODUCTION
Reverse engineering is the opposite of forward engineering. It takes an existing
product ,and creates a CAD model, for modification or reproduction to the design aspect of
the product. It can also be defined as the process or duplicating an existing component by
capturing the components physical dimensions. Reverse engineering is usually undertaken in
order to redesign the system for better maintainability or to produce a copy of a system
without access to the design from which it was originally produced. With this knowledge,
computer vision applications have been tailor to compete in the area of reverse engineering.
Computer vision is a computer process concerned with artificial intelligence and image
processing of real world images. Typically, computer vision requires a combination of lowlevel image processing to enhance the image quality (e.g. remove noise, increase contrast)
and higher level pattern recognition and image understanding to recognize features present in
the image. Three-dimensional (3D) computer vision uses two-dimensional (2D), images to
generate a 3D model of a scene or object.
There has been a mandatory need for 3D reconstruction of scenes and objects by the
manufacturing industry, medical industry, military branches and research facilities.
Manufacturing industry utilizes reverse engineering for its fast rapid prototyping abilities and
accuracy associated with the production of new parts. This fast prototyping is done.
For each existing product the generation of 2d drawing is not possible as the shape is
continuously changing. For those components 3d cad model is generated by using 3d
scanning process. 3D scanning is a fast and accurate method of putting physical
measurements of an object onto the computer in an organized manner, resulting inwhat is
commonly called 3D scan data. Typically, the 3D scan data is represented with a scale digital
model or a 3D graphical rendering. Once the scan data is on the computer, all of the
dimensions of the physical object can be taken, such as length, width, height, volume, feature
size, feature location, surface area, etc.3D scan data is often used as a bridge between
physical objects and modern manufacturing. This is achieved by converting the data into
computer-aided design (CAD) models, using it to compare against the "as-designed" ideal of
the part.

3D Laser Scanning or 3D Laser Scanners can generally be categorized into three main
categories - laser triangulation, time of flight and phase shift. These laser scanning techniques
are typically used independently but can also be used in combination to create a more
versatile scanning system. There are also numerous other laser scanning technologies that are
hybrids and/or combinations of other 3D scanning technologies such as accordion fringe
interferometry or conoscopic holography.

Laser triangulation is accomplished by projecting a laser line or point onto an object

and then capturing its reflection with a sensor located at a known distance from the laser's
source. The resulting reflection angle can be interpreted to yield 3D measurements of the part.

Time of flight laser scanners emit a pulse of laser light that is reflected off of the
object to be scanned. The resulting reflection is detected with a sensor and the time that
elapses between emission and detection yields the distance to the object since the speed of the
laser light is precisely known.

Phase shift laser scanners work by comparing the phase shift in the reflected laser
light to a standard phase, which is also captured for comparison. This is similar to time of
flight detection except that the phase of the reflected laser light further refines the distance
detection, similar to the vernier scale on a caliper.
White Light Scanning (structured light scanning) is used to describe a wide range of
3D scanning devices. The basic technique is to project a known pattern of light (usually
white) and use sensors (typically CCD cameras) to capture images of the object with the
patterns projected on it. In order to capture 3D information, multiple patterns and/or multiple
sensors can be used. If multiple patterns are projected, the software uses referencing and the
change in shape of the known pattern to interpret 3D measurements. If multiple sensors are
used the software uses the known pattern and referencing between image angles to determine
the 3D measurements.
The main disadvantage of using commercial scanners is the cost involved with it. The
commercial scanners are about 1000 of dollars . it creates the limitation of its use in low cost
projects . This created the opportunity of developing the low cost 3d scanners which can
produce good results with out much comprising in quality in comparison to commercial 3d
scanners.
4

Chapter2
LITERATURE REVIEW

3D

laser

scanning

measurement

system

integrating

the

techniques of reverse engineering is adopted in this study to provide a

more accurate measurement of the weld profile. The proposed 3D laser
scanning system with integrated CAD software can provide a more
accurate and efficient method to estimate the geometric quality of a fillet
weld.[1]
An integrated technique of 3D scanning with reverse engineering
and rapid
prototyping technologies. This will be applied to the entire quality control
phase of quick response products during the manufacturing process. By
using 3D scanning and reverse engineering technology in conjunction with
rapid prototyping technology, the
geometric data of components can be easily and rapidly measured and
analysed. The proposed technique is especially suitable for fragile or soft
material made products, like thin shell or rubberparts. With its accuracy
and ease of operation, this integrated
method

is

able

to

help

manufacturers

improve

their

global

competitiveness.[2]
A hand-held 3D scanning technique is proposed to reconstruct 3D
models of real objects .A sequence of range images captured from a handheld stereo camera is automatically registered to a reference coordinate
system. The automated scanning process consists of two states, coarse
and fine registration. At the beginning, scanning process starts at the fine
registration state. A fast and accurate registration refinement technique is
used to align range images in a pair-wise manner. If the refinement
technique fails, the process changes to the coarse registration state. A
5

feature

based

coarse

registration

technique

is

proposed

to

find

correspondences between the last successful frame and the current

frame. If the coarse registration successes, the process returns to the fine
registration state again. A fast point-to-plane refinement technique is
employed

to

alignment,

do

shape-based

texture-based

registration.

refinement

After

technique

the

shape-based

matches

texture

features to enhance visual appearance of the reconstructed models.

Through a graphic and video display, a human operator adjusts the pose
of the camera to change the view of the next acquisition. Experimental
results show that 3D models of real objects are reconstructed from
sequences of range images.[3]
Low-cost and

high-accuracy 3D face measurement is becoming

increasingly important in many computer vision applications including face

recognition, facial animation, games, orthodontics and aesthetic surgery.
In most cases fringe projection based systems are used to overcome the
relatively uniform appearance of skin. These systems employ a structured
light camera/projector device and require explicit user cooperation and
controlled lighting conditions. 3D acquisition solution with a 3D space-time
non-rigid super-resolution capability, using three calibrated cameras
coupled with a non calibrated projector device, which is particularly suited
to 3D face scanning, i.e. rapid, easily movable and robust to ambient
lighting variation. The proposed solution is a hybrid stereovision and
phase-shifting approach, using two shifted patterns and a texture image,
which not only takes advantage of stereovision and structured light, but
also overcomes their weaknesses. The super-resolution scheme involves a
shape texture 3D non-rigid registration for 3D artifacts correction in the
presence of small non-rigid deformations as facial expressions.[4]
The optical control of3D scanners is mature enough, many factors may influence the
quality of the scanned data. These factors may be strictly related to internal elements to the
acquisition device, such as scanner resolution and accuracy, and external to it, such as proper
selection of scanning parameters, ambient lighting and characteristics of the object surface
being scanned (e.g. surface colour, glossiness, roughness, shape), as well as the sensor-to6

surface relative position. For the 3D laser-based scanners, the most common on the market, it
would be of great industrial interest to study some scanning factors mainly affecting the
quality of the 3D surface acquisitions and provide users with guidelines in order to correctly
set them so to increase the massive usage of these systems in the product inspection activities.
In this context, by using a commercial triangulation3D laser scanner, the effects of some
scanning factors that may affect the measurement process were analysed in the present paper.
The scanner-to-object relative orientation and the ambient lighting, as well as an internal
scanner parameter, were tested.[5]

Chapter 3
PROBLEM

FORMULATION

With the rapid pace of development of new product, the shape of

the components are getting complex. Instead of forward engineering, the
role of reverse engineering in product development is significantly
increased. The reverse engineering involves the usage of 3d scanners for
the scanning of complex 3d shapes to produce the 3d cad model and also
the inspection of the manufactured components. The cost involved with
commercial 3d scanners are of the order of 1000 of dollars. There is
subsequent need to make this 3d scanning affordable. Researchers have
develop several low cost 3d scanners using line lasers and webcam, also
video projectors and ccd cameras.
The scope is to develop the experimental set up for the low cost
scanners and its scanning results are compared with the result obtained
from the commercial scanner.
7

OBJECTIVE

To develop the experimental set up of low cost 3d scanner.

To improve the quality of 3d scanning obtained from low cost 3d

scanner.
To make the 3d scanning affordable.

REFERENCES
[1] C.L. Chang ,Y.H. Chen, Measurement of Fillet weld by 3d laser
scanning system

,International Journal of Advance Manufacturing

Technology , Vol. 25, pp. 466 -470,(2005).

[2] A.W.L. Yao, Applications of 3D scanning and reverse engineering techniques
for quality control of quick response products, International Journal of Advance
Manufacturing Technology , Vol. 26, pp. 1284-1288,(2005).

[3] S.Y. Park, J. Baek , J. Moon, Hand-held 3D scanning based on coarse and
fine registration of multiple range images,

Machine Vision and

Applications , Vol. 22, pp. 563-579,(2011).

[4] Karima Ouji , Mohsen Ardabilian , Liming Chen , Faouzi Ghorbel, 3D Deformable
Super-Resolution for Multi-Camera 3D Face Scanning, Journal for Math Imaging
Visualisation , Vol. 47, pp. 124-137,(2013).
[5] Salvatore Gerbino, Et al. , On the influence of scanning factors on the laser scannerbased 3D inspection process , International Journal of Advance Manufacturing
Technology , Vol. 22, pp. 128-131,(2015).