Featured Product
This Week in Quality Digest Live
CMSC Features
Atul Minocha
It’s all about ROI
Ryan E. Day
September Speaker Series in review
Ryan E. Day
Realigning a cornerstone of industry
David H. Parker
Practical implications for electronic distance measurement
Belinda Jones
Users of CMMs, industrial scanners, and portable metrology systems are urged to participate

More Features

CMSC News
Voting for 2022–2023 term will open at CMSC 2022 starting July 25
New facility in Toronto area will showcase multiple Hexagon product lines
API division named ‘Top External Provider 2018’
Exact Metrology selected for project
Faster and more powerful than ever before
Accurate measurement out of the box
Engineering and design teachers will benefit from enhanced 3D scanning performance
Partnering with FARO Technologies

More News

Accurex

Accurex’s default image

CMSC

More Than One Way to Scan a Cat

Published: Tuesday, November 12, 2013 - 15:05

Untitled Document

Although 80 percent of Accurex’s business lies in the industrial application of precision metrology and scanning, the company always enjoys the occasional cultural heritage project. When the Accurex team was called upon to scan the Sphinx of Hatshepsut, it was ready for the challenge.

Hatshepsut was the principal queen of her half-brother, Pharaoh Thutmose II. After he died she became regent for Thutmose III, her stepson and nephew. She adopted the title of Pharaoh, making her the young prince's senior co-ruler. Sculptures of Hatshepsut soon depicted the queen in male regalia.

After Hatshepsut died, Thutmose III ordered the dismantling of all male representations of her. Thousands of statue fragments, discovered in two pits near Hatshepsut’s funerary temple, have been painstakingly reassembled by scholars at the Metropolitan Museum of Art.


Figure 1: Sphinx of Hatshepsut


Figure 2: Djeser-djeseru

The Colossal Sphinx of Hatshepsut, which was scanned by Accurex Measurement, is most likely one of a pair of protective works that were placed symmetrically on the lower terrace of Hatshepsut’s mortuary temple, Djeser-djeseru (“Holy of Holies”), in the western Theban site of Deir el-Bahri.

The sphinx’s body is a recumbent lion and its head is that of Hatshepsut adorned with the male royal headdress and false ceremonial beard. It has a bull’s tail that is indicative of ancient Egyptian royalty’s powerful procreative ability.

Scanning the sphinx


Figure 3: Scanning the sphinx

The Sphinx was scanned using a Breuckmann SmartScan white light scanner that produces high-resolution 3D scans with millions of data points. Although the close-range scanner is a robust solution for industrial and engineering applications sucxh as quality inspection and reverse engineering, it generates 3D scan data that is also very useful in archeology, paleontology, and cultural heritage applications for dimensional analysis and study. 


Figure 4: Photogrammetric reference targets

For a project such as this, which contains many hundreds of scans, automatic alignment of the scans is a useful capability. The graphical representation of the scans on the screen shows in which areas data are missing, and these gaps can be closed by taking additional scans. The technique of automatic alignment cuts down on the number of scans that would be needed if a method such as using the geometry of adjacent scans were used for alignment purposes. Using the geometry of adjacent scans to align them would require approximately 50 percent more scans.


Figure 5: Scanner projects fringe patterns

The basic scan of the sphinx was conducted using the Breuckmann scanner set to a large (700 mm) field of view. A unique capability of the scanner is that it can be easily and quickly reconfigured to a smaller field of view by switching the carbon-fiber base bar between the camera and projector. This was especially useful for this application because certain areas on the sphinx, such as those between the forelegs, contain intricate hieroglyphics. For these areas a scanner configuration with a field of view of 200 mm was used. Because each scan captures the same number of points but over a smaller area, much higher resolutions can be achieved.


Figure 6: Automatic recognition of photogrammetry
targets

Results

More than 200 scans were required for complete coverage of the sphinx. The completed model contained many details that are difficult to see with the naked eye. The final result was delivered in STL format, which can be used for analysis, archiving, or creating replicas.

Recently, Hatshepsut herself has been in the news. Her remains were long considered lost, but in June 2007 a mummy from Tomb KV60, known as the “Strong One” was publicly identified as her remains by means of a DNA comparison with the mummy of Ahmose Nefertari, Hatshepsut’s grandmother.


Figure 7: Final model showing individual overlapping scans

Discuss

About The Author

Accurex’s default image

Accurex

Accurex has years of experience in precision dimensional metrology and scanning. Accurex has expanded its product offering to include a range of advanced portable 3-D coordinate measurement systems. We have been expanding our staff with highly experienced individuals to bring knowledge and ideas that help us understand the issues and challenges facing your business.

Comments

A 3D World

I'm still wondering how Man has built such marvellous costructions thousands years before 3D measuring machines were invented. May be that, after all, Man's eyes are not so blind.