Worksheet #9A
Image Processing 1: Binary Images and Detecting Connected Components

                                             Name ______________

Preliminary work: Run the two programs from "Starting Image Processing
with Lisp" (see the link above) - arrayStarter.lsp and readFile.lsp.
Understand how each works before moving on.  Also read about image file
formats PGM and PPM and the introduction to the concept of 4 and 8 
connectivity of components in images.

1. A. Copy the image file: /home/atlas1/ai/image1.pgm.  
   B. Load the image using xv and magnify sufficiently so you can
      see the 8 by 8 image.
      (xv &   then right click for the menu)
   C. Copy the starter Lisp file: /home/atlas1/ai/connect4Starter.lsp.

2. A. Threshold the image so that all values below 100 are set to 0 and
   all values equal to or above 100 are set to 255.  Write the image
   to a file named "binary1.pgm".  The file should look like this.
   This file should have the following header lines:
   P2
   # Comment line identifying this as a PGM binary image, binary.pgm
   8 8
   255
   - the image pixel values should be here, 8 rows and 8 cols.
   
   B. View binary1.pgm with xv to check if the objects are
   in black against a white background.

3. A. Complete the program connect4.lsp that labels and counts all
    "4-connected objects" in the picture.  Print both the binary
    image and the labeled component image on the screen.
    View a sample output.
   B. Write connect8.lsp to label and count the "8-connected" objects
    in the image. View sample 8-connected labeled image.