the procedures which transfer the bitmap information between pict file and mac common lisp environment

[yooncs@Athena.MIT.EDU]

Hello, I am a graduate student in the dept. of architecture at MIT.  I shouled be very grateful if you could help me.  I am doing a research on analysing architectural plans.   And using mac common lisp I have been making a program which which automates my analysis procedures and I almost finish my work in mac common lisp environment.   My lisp program is made to work on the array data structure in such a way that 0 represents white pixel and 1 represents black pixel. 
 a example for a square 
((0 0 0 0 0 0 0 0 0)
 (0 1 1 1 1 1 1 1 0)
 (0 1 0 0 0 0 0 1 0)
 (0 1 0 0 0 0 0 1 0)
 (0 1 0 0 0 0 0 1 0)
 (0 1 0 0 0 0 0 1 0)
 (0 1 0 0 0 0 0 1 0)
 (0 1 1 1 1 1 1 1 0)
 (0 0 0 0 0 0 0 0 0))

 As I want to make my program directly analyze a plan image which is scanned and stored in pict file format, I am in need of the procedures of retrieving the bitmap information from a mac pict file and rewriting the bitmap information on a mac pict file in mac common lisp environment.  These procedures are very crucial for my graduation and I am desparately in need of this procedures of bitmap information transfer.  Please help me.  I would appreciate you for a way to make those procedures, actual codes, or any comments if you know about this problem.  Thank you for your attention.