Documenting Mackenzie Inuit Architecture Using 3D Laser Scanning

Dawson, Levy, Arnold, Oetelaar, Lacroix1

Documenting Mackenzie Inuit Architecture Using 3D Laser Scanning

Peter C. Dawson, Department of Archaeology, University of Calgary, 2500 University Dr. NW. Calgary, AB. T2N 1N4

Richard M. Levy, Faculty of Environmental Design, University of Calgary, 2500 University Dr. NW. Calgary, AB T2N 1N4

Charles Arnold, Prince of Wales Northern Heritage Center, Yellowknife, NWT

Gerald Oetelaar, Department of Archaeology, University of Calgary, 2500 University Dr. NW. Calgary, AB. T2N 1N4

Dominic Lacroix. Department of Archaeology, University of Calgary, 2500 University Dr. NW. Calgary, AB. T2N 1N4








• Introduction

– Architectural variability often reflects social processes.

– The transition from single to double to triple platform houses in Mackenzie Delta may indicate changes in household organization.

– However, the study of the meaning behind these architectural transitions hindered by:

• Variation in how accuracy Inuvialuit architecture has been documented by archaeologists over the past 100 years.

• The destruction of house ruins by the erosion of archaeological sites on the Beaufort sea coast, and East channel of the Mackenzie River.



• Goal

– Laser scanning provides a means of rapidly capturing architectural information at a levels of detail that may allow us to explore the relationship between house form and culture in Inuvialuit society.

– Demonstration: Laser scanning can be used for the reconstruction virtual 3D models of Inuit Sod Houses



• Location

– Pond Site (NiTs-2).

– Several clusters of house depressions

• Cultural Affiliation

– Inuvialuit - regional groups of ancestral Inuvialuit

• Chronology

– Occupied since 1300 AD



• Previous work – Prince of Wales Northern

Heritage Centre conducted excavations at two of the house depressions at the Pond Site in 1989

– In 2002 the Prince of Wales Northern Heritage Centre returned briefly to the Pond site in order to test whether ground penetrating radar was effective in detecting subsurface archaeological features in permafrost environments.


Documenting Mackenzie Inuit Architecture Using 3D Laser Scanning• Previous Work

• Summer of 2007, a laser scanner was used to record the excavation of two Inuit Sod houses located in the Mackenzie Delta, NWT

NiTs-2 is located on the west shore of Richards Island at 69o 20.6’N and 134o 03.3’W

Towards the mouth of the East Channel of the Mackenzie River



• Why use a laser scanner to capture data

– Challenges

• Expense

• Logistics

• Cost of processing

– Opportunities

• Complete record

• Baseline for 3D construction in a CAD environment



CYRAX2500HDS6000

• Laser Scanner Selection

– Pulse – Time of Flight

• Resolution 6 -10 mm

– Point accuracy vs model space

• Range

– 50 to 400 m.

• Field of View

– 360 horizontal

– 270 vertical

• Pts. per second

– 5000 to 500,000

• Cost

– $100,000 US +



• Issues:

– Laser Scanner Selection

• Modulating Light

– Resolution – 3mm at 20 m

– Range – .6 to 20 m

– Field of View

» 360 horizontal

» 320 vertical

– Pts. per second - 120,000pts

– Color – 24 bit

– Cost – $100,000 US



• Laser Scanner Selection

– Phase

• Resolution - .03 mm (Z)

• Range - .6 to 2.5 m

• Field of View: Lens dependent

– Telephoto Lens: 111 x 84 x 40mm to 460 x 350 x 130 mm

– Mid Lens:196 x 153 x 70 mm to 830 x 622 x 220 mm

– Wide Lens:355 x 266 x 92 mm to 1200 x 903 x 400 mm

• Pts. per second – 300,000

• Color - 24 bit 640x480

• Cost - $40,000+



• Choice of Scanner– Two Scanners vs. One

• General Survey vs. High Level of Detail • Decision: Minolta Vivid 910

– Point accuracy vs. Model accuracy• .03 mm vs. Time of flight +/- .6mm

• Acquisition time- 300,000 pts/sec• Weight 25 lbs• Price – used unit within budget



• Issues:– Logistics

• Transport– Helicopter and quad

• Weather– Temperature and humidity

» 10 to 40 C» 65% or less

– Lighting conditions• Electric Power

– Generator and UPS– Time Constraints

• One day per site



• Data Collection: Laser Scanning

– Occlusion

House 4




– Overlap

• Targets

• Orphaned Polyfaces

House 3




– Field of View

House 3

Telephoto 111 x 84 x 40mm 460 x 350 x 130 mm

Mid Lens 196 x 153 x 70 mm 830 x 622 x 220 mm

Wide Angle 355 x 266 x 92 mm 1200 x 903 x 400 mm




– Field of View

– Setup Time

House 3

Telephoto 111 x 84 x 40mm 460 x 350 x 130 mm

Mid Lens 196 x 153 x 70 mm 830 x 622 x 220 mm

Wide Angle 355 x 266 x 92 mm 1200 x 903 x 400 mm



• Data Collection: Color– From digital imagery vs. scanner

• Issues– Light levels– Reflectance

» Soil moisture– Resolution– Color Depth



• Data Processing

– Polyworks 10.1

• Point Cloud

– 90,000,000 points in two days

– Mesh files

• From points to polyfaces



Laser Scanning I

Output formats: CDM

Laser Scanning I

Output formats: CDM

3d Studio

Input Format: OBJ

Output Format: MAX

3d Studio

Input Format: OBJ

Output Format: MAX

Media Products:

AVI, MOV, QTVR,Tif,JPG

Media Products:


Media/ VR Media/ VR VR:

VirtoolsVR:

Virtools

Polytrans

Input Format: OBJ

Output Forma: 3DS

Polytrans

Input Format: OBJ

Output Forma: 3DS



Laser Scanning I

Output formats: CDM

Laser Scanning I

Output formats: CDM

3d Studio

Input Format: OBJ

Output Format: MAX

3d Studio

Input Format: OBJ

Output Format: MAX

Media Products:


Media Products:


Media/ VR Media/ VR VR:

VirtoolsVR:

Virtools

Polytrans

Input Format: OBJ

Output Forma: 3DS

Polytrans

Input Format: OBJ

Output Forma: 3DS


Documenting Mackenzie Inuit Architecture Using 3D Laser Scanning• Recommendations

– Two scanners

• General survey work – Time of flight for general survey work

• Detail scanning – Triangulation scanner (Minolta Vivid 910)

– Registration

• Targets - Improve the legibility of the 3D targets with less reflective targets


Documenting Mackenzie Inuit Architecture Using 3D Laser Scanning• Recommendations

– Control light levels

• Portable Structure

• Increase lighting levels with daylight flouresent

– Control the distance from scanner to object

• Rail system for mounting the scanner

• Maintain constant distance to object

–


Documenting Mackenzie Inuit Architecture Using 3D Laser Scanning• Conclusions

– Laser scanning offers a means of rapidly documenting Inuvialuit architecture at high levels of resolution, and in a standardized fashion.

– Our research indicates that the use of laser scanning technology is possible in remote environments like the Canadian Arctic.

– Documenting Inuvialuit sod houses at high resolutions will enable archaeologists to examine the possible social and ideological significance of variability in circumpolar architecture


House 4House 4












Documenting Mackenzie Inuit Architecture Using 3D Laser Scanning

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