Project Name: perimeter.dpj

Project Type:
    ADSP-BF533 [X]
    ADSP-BF537 [ ]
    ADSP-BF561 [ ]

Hardware Used:
    ADSP-BF533 EZ-Kit
    VisualDSP++ Emulator

System Services Components Used:
    None

OVERVIEW
========
The perimeter function produces the boundary of a binary image.  The boundary is detected
by examining the neighboring  pixels.  The pixels used for calculations are

                        p_top
          p_left     p_boundary     p_right
                        p_bottom

if p_boundary ==1 and any of neighbor pixel under consideration is zero
   then output==1    else output==0;

  The function is demonstrated below by Equivalent  C code.

           if (((p_top==0)|| (p_left==0) || (p_right==0) ||
               (p_bottom==0) ) & (p_boundary==1))
                output=1;
           else
                output=0;

This is implemented  using a mask
                       | 0   1   0 |
                       | 1  -4  1  |
                       | 0   1   0 |

and comparing the result for nonzero value. In output image, first row,last row, first column
and last columns are same as input.

This will work only if the number of columns in the input image is an even number and aligned
to 4 byte or 2 byte boundary.

Prototype:
         void _perimeter(unsigned char* in, int row, int col, unsigned char *out );

Arguments:
       in   - pointer to the input image.
       row  - number of rows of input image.
       col  - number of columns of input image.
       out  - pointer the output buffer.

Registers used  : A0, A1, R0-R3, R5-R7, M0, M1, P0-P5, LC0, LC1.




RUNNING THE APPLICATION (on the ADSP-BF533 EZ-KIT Lite)
=======================================================

1) Load project "perimeter.dpj".

2) Select "Project->Rebuild Project"

3) Select "Debug-> Run".

4) Observe output on VisualDSP++ console window.




Files in This Application
==========================

This example consists of the following files:

    "./perimeter.ldf" - linker description file
    "./perimeter.dpj" - project file
    "../../src/t_perimeter.c" -  source file
    "../../src/perimeter.asm" -  source file
    "../../src/perimeter.h" -  include file
    "../../../../BFinUtils/ADSP-BF561/SDK-cycle_count.asm" -  source file
    "../../../../Include/SDK-cycle_count.h" -  source file