3.1. Define the following in your own words: intensity image, range image, pixel.

3.2 On page 36 the author suggests "quantizing" a 525 line television image into a 640 x 480 VGA display. But there are 525 lines in the TV image and 480 lines in the VGA display. How can this be done? Suggest two ways and discuss the advantages and disadvantages of each.

The "Iris" stations described on page 58 are Silicon Graphics (SGI) workstations. We have three SGI O2 machines which will be available to this class. They have video capture capability as described here.

3.3 Twenty-four bit vs. 8 bit color. A "color palette" is a list of triples; for instance, it might consist of a list of 8-bit values for red, green and blue. A 256 color image would use 8 bits per pixel to store index values into a color palette. Describe how it is possible to take a 24 bit color image and store it as an 8 bit palette-based image. The expression "histogram" should occur in your description. (This query is based on the lecture and not the text.)

3.4 Chapter 4 is divided into two major sections, concerning 'image format' and 'graphics format' for pictures. Another set of equivalent terms is pixel-image versus scene geometry. Describe the analogy between the image/graphics relationship, and the relationship between .wav tables and MIDI sound files. Name a few graphics primitives in your explanation.

Dr. Moshell asserts that one scene geometry can generate an infinite number of images. How?

3.5: What is "rendering?" What might we call the analogous audio process?

Note: This chapter frequently cites a reference named FDFH. Anyone in the graphics business instantly recognizes "Foley, van  Dam, Feiner & Hughes" which is the Bible of computer graphics. If you are planning to be in this business, you need to understand what's in FDFH. Basically that's what is taught in CAP5725, although they don't use FDFH as the text any longer.

The text describes SRGP, as "Simple Raster Graphics Package". SRGP was defined in FDFH, but is not in actual use anywhere except maybe a few universities. The most common graphics library now is called OpenGL. It is based on Silicon Graphics' GL (Graphics Library, obviously.) Two predecessors to SRGP were GKS and PHIGS.

3.6. (These terms come from the lecture.) Describe the idea of relative and absolute coordinates. Describe positional and velocity-based controls. Use these terms to explain the action of a mouse, a joystick and a graphics tablet, which are three of the most commonly used graphical input devices.

3.7: Dithering is a topic of considerable importance, not well explained here. It is based on a discrete version of the classic halftoning process in printing. Explain the similarity in general terms.

Image recognition - also called machine vision. A deep subject, about which I don't plan to ask you.

3.8: Image transmission. Briefly discuss the advantages and disadvantages of raw, compressed and symbolic "image" transmission as described by the text. Why does Dr. Moshell object to the third term?