STRUCTURE AND FORMAT

About the Sections

The images that make up the VisTex database are stored in a flat directory structure (VisTex/Images/FLAT) according to image size. The 4 sections of the VisTex database are accessed through a directory hierarchy that contains symbolic links to the images in the flat directories. By using symbolic links, images may appear in several categories, but are stored once. The images in this sense are separated from the classification system.

Reference Textures

In the case of the Reference Texture section the images are grouped according to what they are. The (VisTex/Images/Reference) directory contains groups such as grass, water, brick, buildings, clouds, . . . etc. Within these directories are the symbolic links to the actual files.

Texture Scenes

The Texture Scenes section is arranged so that the links to all images relating to a scene are in the same directory. The name of the scene directories come from the dominant textures in the scene. Within each scene directory (i.e. VisTex/Images/Scenes/GrassPlantsSky) there is a file / symbolic link named context1.ppm. This file is either a 786x512 or 512x786 image depending on the orientation of the scene. The other files in the directory are texture patches (usually homogeneous) taken from within the scene. While these detail patches are visible within the context scene, they are taken from alternate images so that the perspective and lighting varies slightly between the context and detail image.

Video Textures

This section will be included in a future release of VisTex.

Video Orbits

This section will be included in a future release of VisTex.

General Information

File Formats and Image Size

All images in the Vision Texture database are stored as raw ppm (P6) files. Currently there are 2 standard sizes for images in VisTex: 512x512, and 128x128. All images in the Reference Texture section and the texture patches from Texture Scenes are available in these sizes. The context images for the Texture Scenes section are 786x512 and 192x128. Vertically oriented images are available at 512x786 and 128x192. In most cases, the textures in the database are available by special request up to 3072 x 2048. If you need software to read or convert ppm files, we recommend using a free software tool like ImageMagick's Convert or the GNU Image Manipulation Program. These programs are available for a variety of platforms.

Annotations

Annotations for the images are stored in the header of each ppm file. The current annotations for the database include:

content
lighting
perspective
Brodatz replacement number
image source
notes

The ppm header for this image of tree bark looks like this:

	P6
	# CONTENTS tree bark
	# LIGHTING daylight direct right
	# PERSPECTIVE frontal plane
	# BRODATZ D13
	# SRC PCD 3174 2022 0103 #46
	# NOTES -
	512 512
	255

Comment lines in ppm files begin with #. VisTex uses comment lines to store image annotations. The capitalized word after # is the annotation tag. Anything following the annotation tag is considered the value of the tag. A list of current annotation tags and their possible values is available.

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3/25/95 - Chris Graczyk - cgraczyk@media.mit.edu