Retrieval of Petroglyph Images from a Database using Image Information
Huyser, Cynthia Gaye
A method of retrieving petroglyph images from a database using image information is proposed. Image preprocessing prior to retrieval is discussed, and a method for automated threshold extraction is developed. Image retrieval using a line-histogram method developed by Huet and Hancock (1998, 1998) and a centroid-radii model based on the work of Tan, Ooi, and Thiang (2000) are investigated. The centroid-radii model, when modified to accommodate missing image information and used with normalized Euclidean distance measure, was effective in retrieving similar images from a field of 437 images when the distance between images was less than 30. Preprocessing and retrieval procedures were implemented in C code. The automated threshold extraction is O(n + m2), where n is the number of pixels in the bounding box of a selected region-of-interest and m is the number of grayscale intensities in which the image is encoded; extraction of the centroid-radii distance measure is O(n), where n is the maximum dimension of a side of the bounding box, and calculation of the distance between two images in the database is O(n2) in the number of radii used to describe an image. A user survey of perceived similarity between query images and resulting retrieval sets demonstrated a direct correlation between the average distance of the retrieved image to the query image and the number of images in the retrieval set perceived as similar to the query image. A cluster analysis performed using the distance measure showed that the most meaningful clustering of images occurs at small distances.
image processing, photography, computer vision, petroglyphs, digital techniques
Huyser, C. G. (2002). Retrieval of petroglyph images from a database using image information (Unpublished thesis). Southwest Texas State University, San Marcos, Texas.