IUCN / SSC Cat Specialist Group - Digital Cat Library |
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| Galentine, S.P.; Fitzhugh, E.L. | |
| Standardizing photographs of puma tracks for digital processing Abstracts Fifth Mountain Lion Workshop 27.02.-01.03., 1996 Bahia Hotel, San Diego, California | |
| 1996 Conference Proceeding | |
Scientific attention has recently been directed toward the use of animal tracks for identification of species, for population indices, and for identification of individuals. One aspect of some of these techniques involves computerized analysis of the tracks to determine measurements and areas within and among different parts of the track. To accomplish computer analysis, the track outlines and other features must first be identified (digitized) for the computer. Tracks traced on acetate or plastic film are relatively easily and accurately digitized, but tracing the tracks in the field requires valuable field time and contains an error component because of parailax and variable field conditions surrounding each track. Photographs greatly reduce field time, and can eliminate the parallax error if they are taken from a location perpendicular to the substrate the track is on (not necessarily vertical). Photographs, however, must be digitized in the office. If the photographs are of variable quality and size, the human error involved in identifying the true outlines and features may sometimes be greater than errors made by tracing in the field. This poster illustrates a collapsible, portable camera mount, or "black box" designed to provide photographs of tracks, taken perpendicular to the substrate, of consistent quality and size. Tests were done to determine proper exposure settings, filters, and number and location of flash units. Examples of tracks photographed using the equipment are included in the poster. Schematic drawings of the box with a materials list are available for those who wish to construct their own "black box". Individual experimentation is advised prior to collecting field data, because variations may occur in power of various flash units and photographic quality of material used to filter the flash intensity. |
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