Graphic file formats tutorial and
assignment

COT 2030 Input Output Technology

This is the third COT2030 assignment.

Assignment requirements:

• Due date: 12:00 noon Monday Week 13 semester 1, 1997
• Marks: 5% of the marks for COT2030
• To get a pass will take about 1 - 2 hours
• Work alone.
• Work through the instructions on this world wide web page, http://www.ct.monash.edu.au/~cavram/Cot2030/picfiles/picfiles.htm
• Hand in your written answers to the questions.

Use this world wide web page to

• learn about various graphics file formats,
• to get a shareware file format converting program,
• as a working guide for the third assignment.

You must complete the tasks labelled with a yellow ball, thus

Complete this task.

Graphics file formats - practical exercise

Information on graphic file formats:

• The Graphic Utilities' Site & Version FAQ;
• Graphics viewers, editors, utilities and info;
• An example graphic file format specification: CCITT (ITU/T) Group 3 fax format, also called TIFF file format. TIFF is a file format that allows a variety of picture encodings to be used, G3 is just one of them;
• Directory of picture file format specifications;

Graphic file formats used in business:

• Business documents tend to be A4 paper, black and white, high contrast (no greys). A4 paper is (about) 8x11 inches. At 300 dots per inch an A4 page has 7,920,000 pixcells, each one bit (black or white), so would take 990,000 bytes (almost one mega byte). One recent law case in Melbourne involved around 1,000,000 A4 pages of paper. One million mega bytes is a lot of data. A better coding system is needed.
• The professional format for high contrast black and white pictures, such as those from document imaging business correspondence, is TIFF group 4. This is also the format used by the Monash library for past exam papers. One of the industry standard software packages for TIFF Group 4 document imaging and document management is the Eastman (Kodak) software, first written by Wang. This software is available at the Desktop Imaging Home Page/Eastman Software. The TIFF file format reduces an A4 legal document to about 25,000 bytes, a compression of 1 to 40;
• Things never stand still, just as the TIFF format was establishing itself as an industry standard, a new format was invented by Cartesian Products, Inc. in 1993. The coding system is called CPC. CPC compresses an A4 legal document to about 3,000 bytes, a compression of 1 to 8 compared to TIFF and overall a compression 1 to 330.

Here is a table showing approximate file sizes for various picture file formats or coding systems. The table lists the file size for a typical A4 page of typed text as is used in business.

File format	File size	Compression type
JPEG	1,000,000	Lossy
BMP	990,000	None
GIF	250,000	Lossless
TIFF	25,000	Lossless
CPC	3,000	Lossy

Your assignment task is to create such a table for a colourful picture OR compare coding systems in different uses.

ONLY ANSWER ONE QUESTION.

Either Question: (5 marks)

• Get a copy of Lview3.1;
• install Lview3.1 on the Lab PC;
• take a picture file from the web, or create one using Microsoft Paint (or any other paint program);

Hint: Click the right mouse button on a picture in netscape, choose Save Image As ...

• use a picture of between 100x100 and 400x400 pixcells;
• prepare a table of formats and file sizes for your picture;

Hint: Open the picture in Lview, save it using Save As ...

• your table should contain at least the following three file types .bmp, .jpg and .gif;

Hint: If you are looking for an extension, (1) try other programs and other file formats (2) try a variety of Jpeg file format parameters in Lview (3) explain what the parameters in Jpeg mean (4) explain why jpeg is a better than GIF when compressing for pictures but is worse for A4 black and white high contrast pictures.

OR Question (only answer one question): (5 marks)

Why is .jpg a better compression system than .gif in the case of colourful pictures like the following, but worse than .gif for black and white pictures like that below?

Hand in your assignment in week 13.