source photographs. The technology, stemming from the development of Polynomial Texture Maps (PTMs) originally invented by Tom Malzbender at Hewlett Packard Labs in 2001, utilizes a single camera and circles the target surface or object with rotating, raking lighting sources, taking a new digital image with each position change. Each photograph registers the same surface details with minute changes in reflection and in ways that promote registration and measurement of the specific relief, design, and deterioration characteristics of the objects being photographed. The second approach is currently being used by Red Fish, Inc., a complex-systems imaging and processing software group in Santa Fe, New Mexico. Steve Gurgin at Red Fish projects a structured pattern of light—lines, grids, or geometric patterns—on the subject and records and analyzes the deformations of the pattern on the surface of an object. A camera, offset slightly from the pattern projector, looks at the
The point of this promising technology is to be able to automate accurate measurements and monitor small changes in the condition of our collections.
shape of the line and uses a complex algorithm, similar to triangulation, to calculate the distance of every point on the line. The art and homes of Georgia O’Keeffe at Ghost Ranch and Abiquiú offer a perfect field environment to test these technologies and their ability to docu-
At the front of O’Keeffe’s Abiquiú home, a laptop computer generates a sine-wave light pattern that is projected onto the house using an ordinary digital projector. Each pixel in the photograph can then be fixed as the third point of a triangle with the known distance between the camera and the projector and two known angles.
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