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 // test positions
  12 static double test_left, test_right;
  13
  14 /** Buffer for storing image data. Stored as a  **/
  15 static CvMat * g_data = NULL;
  16
  17
  18 /** Camera capture pointer **/
  19 static CvCapture * g_capture = NULL;
  20
  21 /**
  22  * Create a test image using left as left edge and right as right edge positions
  23  */
  24 void Dilatometer_TestImage()
  25 {
  26
  27         CvMat *g_dataRGB;
  28         g_dataRGB = cvCreateMat(480, 640, CV_8UC3);
  29
  30         for( int x = 0; x < 640; ++x)
  31         {
  32                 for (int y = 0; y < 480; ++y)
  33                 {
  34                         CvScalar s;
  35                         for( int i = 0; i < 3; ++i)
  36                         {
  37                                 s.val[i]  =  210 + (rand() % 1000) * 1e-0 - (rand() % 1000) * 1e-0;
  38                                 // Produce an exponential decay around left edge
  39                                 if( x < test_left)
  40                                         s.val[i] *= exp( (x - test_left) / 25);
  41                                 else if( x < 320)
  42                                         s.val[i] *= exp( (test_left - x) / 25);
  43                                 // Produce an exponential decay around right edge
  44                                 else if( x < test_right)
  45                                         s.val[i] *= exp( (x - test_right) / 25);
  46                                 else
  47                                         s.val[i] *= exp( (test_right - x) / 25);
  48                         }
  49                         cvSet2D(g_dataRGB,y,x,s);
  50                 //      if( s.val[0] > 200)
  51                 //              printf("row: %d, col: %d, %f\n", y, x, s.val[0]);
  52                 }
  53
  54         }
  55         if (g_data == NULL)
  56         {
  57                 g_data = cvCreateMat(g_dataRGB->rows,g_dataRGB->cols,CV_8UC1); //IPL_DEPTH_8U?
  58         }
  59         cvCvtColor(g_dataRGB,g_data,CV_RGB2GRAY);
  60 }
  61
  62 /**
  63  * Initialise the dilatometer
  64  */
  65 void Dilatometer_Init()
  66 {
  67
  68         // Make an initial reading (will allocate memory the first time only).
  69         Dilatometer_Read(1);
  70 }
  71
  72 /**
  73  * Cleanup Interferometer stuff
  74  */
  75 void Dilatometer_Cleanup()
  76 {
  77         if (g_data != NULL)
  78                 cvReleaseMat(&g_data);
  79
  80         if (g_capture != NULL)
  81                 cvReleaseCapture(&g_capture);
  82
  83 }
  84
  85 /**
  86  * Get an image from the Dilatometer
  87  */
  88 static void Dilatometer_GetImage()
  89 {
  90         //Need to implement camera
  91 }
  92
  93 // Test algorithm
  94 static void Dilatometer_GetImageTest( )
  95 {
  96         //Test image
  97         Dilatometer_TestImage();
  98 }
  99
 100
 101 /**
 102  * Read the dilatometer; gets the latest image, processes it, THEN DOES WHAT
 103  * @param samples - Number of rows to scan (increasing will slow down performance!)
 104  * @returns the average width of the can
 105  */
 106 double Dilatometer_Read(int samples)
 107 {
 108         //Get the latest image
 109         //Dilatometer_GetImage();
 110
 111         Dilatometer_GetImageTest();
 112
 113         int width = g_data->cols;
 114         int height = g_data->rows;
 115         // If the number of samples is greater than the image height, sample every row
 116         if( samples > height)
 117         {
 118                 //Log(LOGNOTE, "Number of samples is greater than the dilatometer image height, sampling every row instead.\n");
 119                 samples = height;
 120         }
 121
 122         // Stores the width of the can at different sample locations. Not necessary unless we want to store this information
 123         //double widths[samples];
 124         // The average width of the can
 125         double average_width;
 126         int sample_height;
 127         for (int i=0; i<samples; i++)
 128         {
 129                 // Contains the locations of the 2 edges
 130                 double edges[2] = {0.0,0.0};
 131                 int pos = 0;    // Position in the edges array (start at left edge)
 132                 int num = 0;    // Keep track of the number of columns above threshold
 133
 134                 // Determine the position in the rows to find the edges.
 135                 sample_height = ceil(height * (i + 1) / samples) -1;
 136                 //printf("sample height is %d\n", sample_height);
 137
 138                 //CvScalar test = cvGet2D(g_data, 150,300);
 139                 //printf("test is %f,%f,%f,%f\n", test.val[0], test.val[1], test.val[2], test.val[3]);
 140
 141
 142                 for ( int col = 0; col < width; col++)
 143                 {
 144                         CvScalar value = cvGet2D(g_data, sample_height, col);
 145                         if( value.val[0]> THRES)
 146                         {
 147                                 edges[pos] += (double) col;
 148                                 num++;
 149                         }
 150                         // If num > 0 and we're not above threshold, we have left the threshold of the edge
 151                         else if( num > 0)
 152                         {
 153                                 // Find the mid point of the edge
 154                                 edges[pos] /= num;
 155                                 if( edges[1] == 0)
 156                                 {
 157                                         pos = 1;        // Move to the right edge
 158                                         num = 0;
 159                                 }
 160                                 else
 161                                         break;          // Exit the for loop
 162                         }
 163                 }
 164                 // Determine the width of the can at this row
 165                 //widths[i] = edges[1] - edges[0];
 166                 average_width += (edges[1] - edges[0]);
 167         }
 168         average_width /= (double) samples;
 169         return average_width;
 170 }
 171
 172 /**
 173  * For testing purposes
 174  */
 175 int main(int argc, char ** argv)
 176 {
 177         //cvNamedWindow( "display", CV_WINDOW_AUTOSIZE );// Create a window for display.
 178         //gettimeofday(&start, NULL);
 179         test_left = 100;
 180         test_right = 500;
 181         Dilatometer_Init();
 182
 183         cvNamedWindow( "display", CV_WINDOW_AUTOSIZE);
 184         cvShowImage("display", g_data);
 185         cvWaitKey(0);
 186         double width;
 187         for( int i = 0; i < 20; ++i)
 188         {
 189                 test_left  -= i * (rand() % 1000) * 1e-3;
 190                 test_right += i * (rand() % 1000) * 1e-3;
 191
 192                 //Make sure left and right positions are sane
 193                 if( test_left < 0)
 194                         test_left = 0;
 195                 if( test_right > 639)
 196                         test_right = 639;
 197                 if( test_left > test_right)
 198                 {
 199                         int tmp = test_right;
 200                         test_right = test_left;
 201                         test_left = tmp;
 202                 }
 203
 204                 width = Dilatometer_Read(5);
 205                 cvNamedWindow( "display", CV_WINDOW_AUTOSIZE);
 206                 cvShowImage("display", g_data);
 207                 cvWaitKey(0);
 208                 double expected = test_right - test_left;
 209                 double perc = 100 * (expected - width) / expected;
 210                 printf("%d: Left: %.4f.    Width: %.4f.\n  Right: %.4f. Expected: %.4f. Percentage: %.4f\n", i, test_left, width, test_right, expected, perc);
 211         }
 212 }
 213