server/dilatometer.c

   1 /**
   2  * @file dilatometer.c
   3  * @purpose Implementation of dilatometer related functions
   4  */
   5
   6 #include "cv.h"
   7 #include "highgui_c.h"
   8 #include "dilatometer.h"
   9 #include <math.h>
  10
  11 /** Buffer for storing image data. Stored as a  **/
  12 static CvMat * g_data = NULL;
  13
  14
  15 /** Camera capture pointer **/
  16 static CvCapture * g_capture = NULL;
  17
  18
  19 /**
  20  * Initialise the dilatometer
  21  */
  22 void Dilatometer_Init()
  23 {
  24
  25         // Make an initial reading (will allocate memory the first time only).
  26         Dilatometer_Read(1);
  27 }
  28
  29 /**
  30  * Cleanup Interferometer stuff
  31  */
  32 void Dilatometer_Cleanup()
  33 {
  34         if (g_data != NULL)
  35                 cvReleaseMat(&g_data);
  36
  37         if (g_capture != NULL)
  38                 cvReleaseCapture(&g_capture);
  39
  40 }
  41
  42 /**
  43  * Get an image from the Dilatometer
  44  */
  45 static void Dilatometer_GetImage()
  46 {
  47         //Need to supply test image
  48
  49         //Need to implement camera
  50 }
  51 /**
  52  * Read the dilatometer; gets the latest image, processes it, THEN DOES WHAT
  53  * @param samples - Number of rows to scan (increasing will slow down performance!)
  54  * @returns the average width of the can
  55  */
  56 double Dilatometer_Read(int samples)
  57 {
  58         //Get the latest image
  59         Dilatometer_GetImage();
  60
  61         int width = g_data->cols;
  62         int height = g_data->rows;
  63         // If the number of samples is greater than the image height, sample every row
  64         if( samples > height)
  65         {
  66                 Log(LOGNOTE, "Number of samples is greater than the dilatometer image height, sampling every row instead.\n");
  67                 samples = height;
  68         }
  69
  70         // Stores the width of the can at different sample locations. Not necessary unless we want to store this information
  71         //double widths[samples];
  72         // The average width of the can
  73         double average_width;
  74         int sample_height;
  75         for (int i=0; i<samples; i++)
  76         {
  77                 // Contains the locations of the 2 edges
  78                 double edges[2] = {0};
  79                 int pos = 0;    // Position in the edges array (start at left edge)
  80                 int num = 0;    // Keep track of the number of columns above threshold
  81
  82                 // Determine the position in the rows to find the edges.
  83                 sample_height = ceil(height * (i + 1) / samples) -1;
  84
  85                 for ( int col = 0; col < width; col++)
  86                 {
  87                         if ( CV_MAT_ELEM( *g_data, double, col, sample_height) > THRES)
  88                         {
  89                                 edges[pos] += col;
  90                                 num++;
  91                         }
  92                         // If num > 0 and we're not above threshold, we have left the threshold of the edge
  93                         else if( num > 0);
  94                         {
  95                                 // Find the mid point of the edge
  96                                 edges[pos] /= num;
  97                                 if( edges[1] == 0)
  98                                 {
  99                                         pos = 1;        // Move to the right edge
 100                                         num = 0;
 101                                 }
 102                                 else
 103                                         break;          // Exit the for loop
 104                         }
 105                 }
 106                 // Determine the width of the can at this row
 107                 //widths[i] = edges[1] - edges[0];
 108                 average_width += (edges[1] - edges[0]);
 109         }
 110                 average_width /= samples;
 111                 return average_width;
 112 }
 113