/*------------------------------------------------------------------------------------*/
/*                                  NIGHTVISION.C                                     */
/*------------------------------------------------------------------------------------*/
/* David A. Hess CS455 Assignment 1                                                   */
/*------------------------------------------------------------------------------------*/
/* This program demonstrates a night camera visual system created by performing a     */
/* probablelistic equalization (procedure 'equalize') on the histogram of a dark      */
/* visual scene. The system is initialized in the normal, unequalized video mode      */
/* and remains in that mode until the user makes a selection between test mode and    */
/* night vision mode. Test mode freezes the image and performs and displays the       */
/* unequalized histogram of the image. Then, when requested, performs an equalization */
/* on the frozen image and displays the histogram of the equalized image. Night       */
/* vision mode performs a single equalization on the image and keeps the LUT at       */
/* this level until requested to quit. Continuous equalize mode continuously loops    */
/* through the image equalization routine until control-C is entered.                 */                                                                                                               /*------------------------------------------------------------------------------------*/

#include <stdio.h>
#define YES 1
#define NO 0

   int harray[256];
   int LUTarray[256];

   main()
     {
       int scale = 255;
       char cmd;
       int j;
 
       do
         {
           VIS$OPEN();
           VIS$INIT_FB();
           setcamera(0);
           VIS$INIT_LUTS();
           VIS$VIEW();
           printf("%s%s","Enter command : n (continuous night vision)\n",
                  "c (continuous equalize vision) t (test) e (exit program)");
           cmd = getchar();
           while(getchar() != '\n');
           if (cmd != 'e')
             {
               switch (cmd)
                 {
                   case 'n' : /* begin continuous night vision */
                     {
                       VIS$FREEZE();
                       VIS$CS455_HISTOGRAM(50,50,500,400,NO,harray,255);
                       equalize(harray,LUTarray,scale);
                       VIS$LOAD_LUT(0,1,LUTarray);
                       VIS$SELECT_LUT(0,1);
                       VIS$VIEW();
                       printf("%s","\nNight Vision Mode. Enter 'q' to quit.\n");
                       while(getchar() != 'q');
                       while(getchar() != '\n');
                       break;
                      }
                   case 't' :  /*begin test */
                     {
                       VIS$FREEZE();
                       VIS$HISTOGRAM(50,50,500,400,NO); 
                       printf("%s%s","Displaying unequalized histogram.\n",
                              "Enter <CR> to view equalized histogram.");
                       while (getchar() != '\n');
                       VIS$VIEW(); 
                       VIS$FREEZE(); 
                       VIS$CS455_HISTOGRAM(50,50,500,400,NO,harray,255);
                       equalize(harray,LUTarray,scale);
                       VIS$LOAD_LUT(0,1,LUTarray);
                       VIS$SELECT_LUT(0,1);
                       VIS$SET_MODE(1);
                       VIS$HISTOGRAM(50,50,500,400,NO); 
                       printf("%s%s","Displaying equalized histogram.\n",
                              "Enter <CR> to continue.");
                       while (getchar() != '\n');
                       VIS$SET_MODE(0);
                       break;
                      }       /* end test */
                    case 'c' : /* begin continuous equalize vision */
                     {
                       printf("%s","\nContinuous Equalize Mode. Enter cntl-c to quit.\n");
                       VIS$VIEW();
                       while(1) {
                         VIS$CS_HISTOGRAM(50,50,500,400,NO,harray,255);
                         equalize(harray,LUTarray,scale);
                         VIS$LOAD_LUT(1,0,LUTarray);
                         VIS$LOAD_LUT(2,0,LUTarray);
                         VIS$LOAD_LUT(3,0,LUTarray); }
                       break;
                      }       /* end continuous equalize */
                  }           /* end switch */
              }               /* end if */
           } 
         while (cmd != 'e');
     }   /* end main() */

   equalize(harray,LUTarray,scale)
     int *harray,*LUTarray,scale;
     {
       int N,i,level = 0;
       float s = 0.0;
       N = harray[0];
       for (i = 1;i <= scale;i++) N += harray[i];    /* total pixels */
       for (i = 0;i <= scale;i++) {
         s += (float)harray[i]/(float)N;    /* calc Sk */
         while (((float)level/(float)scale) < s) level++;   /* find scaling level */
         LUTarray[i] = level; }
      }     /* end equalize */

VIS$CS_HISTOGRAM(x1,y1,x2,y2,equalize,harray, color)
  int x1,y1,x2,y2, equalize, *harray, color;
  {
    int i,x;
    int values[641];
    
    /* INITIALIZE ARRAYS */
    for (i=0;i<=255;i++)
    {
      harray[i] = 0;
    }

    /* FILL HARRAY WITH READ_HORIZONTAL_LINE this is the histogram */
    for (i=y1;i<=y2;i++)
    {
      rhline(x1,i,x2-x1,values);
      for (x=0;x<x2-x1;x++)
        harray[ (values[x] & 0x00ff) ]++;  /* for 8 bits only 0..255 */
     }

  }