THE PRINT-SCAN Machine3-D Spatial Mapping Device

Nia CookStephen TanAnil Rohatgi

Senior DesignFinal Report Presentation

ECE4006Spring2005

Introduction

• Project Goal

Use of 3-D imaging techniques to measure the detailed physical structure of the interior of a confined space and map it into a virtual 3-D environment

• Prototype

The PRINT-SCAN Machine

Project Specifications

• 10cm*10cm*10cm cubic volume• Ability to capture physical detail (preferably at

the micron level) • Ability to measure the size and shape of objects• Ability to measure relative positions of multiple

objects within the volume• Cannot employ imaging techniques using x-rays

Project Constraints

• Objects are stationary within volume

• Objects have low reflectivity

• Objects are not in contact with neighbor

• A four month time limit

• Design cannot exceed $500 budget

Component List

• Sharp GP2D12 distance measuring sensor• IR Mirrors• HP Inkjet Printers• HP 5-49A Ink Cartridges• HP 5-29A Ink Cartridges• D1984 Data Capture with WINDAQ software• Constructed ten centimeter volume• Driver Circuit (L298N and SN74LS04N)

Theoretical Design

Project Technical Details

• Box construction– 10 cm cube with open top– Tracks on inside to stabilize mirrors– Flaps on box for data threshold segmentation

• Driver Circuit– SN74LS04N inverter toggles the L298N H-bridge so

that printer moves back and forth– Function generator provides 100 mHz square wave

as input– Power supply inputs 7 – 8 V for reasonable printer

head speed

Project Technical Details

• Laser Sensors– Read distance as a function of voltage– Records voltages in Excel– 10 cm to 80 cm range

• Mirrors– Reflective for 850 nm laser sensor– Angled at 45 degrees to reflect the laser

beam to the object– Incremented upwards to capture object height

Prototype Design

Data Reconstruction• Sensor

characterization• Power regression

line:

8.0082x^(-0.837)• Correlation

percent: 99.64%• Inverse regression

applied to data

Distance 1- Power Regression

y = 8.0082x-0.873

R2 = 0.9964

0

0.5

1

1.5

2

2.5

3

0 5 10 15 20

Distance (in)

Volta

ge (V

)

Series1

Power (Series1)

Data Reconstruction• Data Imported from Microsoft Excel to Matlab for

processing• Data needs to be segmented into vertical divisions

Data Reconstruction

• Matrix structure and corresponding coordinate values

Data Reconstruction• Three reconstruction techniques

Point cloudSpline fit

Mesh Grid

Data Reconstruction• Video demonstration

result:– Attempted to scan

two rubber wheels staggered inside the volume

– Managed to reconstruct shape and location, however, recovering the spacing between the objects did not function.

– Errors were in the data, not in the data processing

Lessons Learned• Scheduling

• IR Sensor Interaction

• Power Drive

• Calculations

Conclusion• Although the device did not perform as well in real life as expected,

there was adequate data to support proof of concept.• With better equipment, and more funding, the design could be

extended to achieve the optimal goals of the project.Initial Specifications: Achieved Specifications:

10cm3 confined volume (top open) The volume is approximately 10 cm3

Capture physical detail, at micron level The actual resolution of the sensors do not give the physical details of the object at the micron level

Measure size and shape of objects Our design outlines the shape of an object

Measure relative positions of multiple objects within the volume

During our product demonstration, we employed two objects, we were able to calculate their positions relative to each other, and however mapping the spacing between the objects was a problem. Occlusion was not a factor.

Cannot employ imaging techniques using x-rays

Our device design, does not employ any x-ray imaging techniques

Questions?

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