// test positions
static double test_left, test_right;
+// Remembers the last position to measure rate of expansion
+static double lastPosition;
+
+
// Canny Edge algorithm variables
int blur = 5;
int lowThreshold = 30;
static CvMat * g_edges = NULL; // Detected Edges
/** Pointers for capturing image **/
-static CvCapture * g_capture = NULL;
-static IplImage * frame = NULL; // This is required as you can not use capture with CvMat in C
+//static CvCapture * g_capture = NULL;
+//static IplImage * frame = NULL; // This is required as you can not use capture with CvMat in C
/**
*/
bool Dilatometer_Cleanup(int id)
{
- if (g_capture != NULL)
- cvReleaseCapture(&g_capture);
- if (frame != NULL)
- cvReleaseImageHeader(&frame);
+ //if (g_capture != NULL)
+ // cvReleaseCapture(&g_capture);
+ //if (frame != NULL)
+ // cvReleaseImageHeader(&frame);
+
//if (g_srcRGB != NULL)
// cvReleaseMat(&g_srcRGB); // Causing run time error in cvReleaseMat
if (g_srcGray != NULL)
}
/**
- * Get an image from the Dilatometer
+ * Get an image from the Dilatometer. Replaced by Camera_GetImage in image.c
*/
-static bool Dilatometer_GetImage()
+/*static bool Dilatometer_GetImage()
{
bool result = true;
// If more than one camera is connected, then input needs to be determined, however the camera ID may change after being unplugged
cvCvtColor(g_srcRGB,g_srcGray,CV_RGB2GRAY);
return result;
-}
+}*/
void CannyThreshold()
{
+ // Convert the RGB source file to grayscale
+ cvCvtColor(g_srcRGB,g_srcGray,CV_RGB2GRAY);
+
if ( g_edges == NULL)
{
g_edges = cvCreateMat(g_srcGray->rows,g_srcGray->cols,CV_8UC1);
}
/**
- * Read the dilatometer image. The value changed will correspond to the new location of the edge.
+ * Read the dilatometer image. The value changed will correspond to the rate of expansion. If no edge is found then
* @param val - Will store the read value if successful
* @param samples - Number of rows to scan (increasing will slow down performance!)
* @returns true on successful read
*/
-bool Dilatometer_GetEdge( double * value, int samples)
+bool Dilatometer_GetExpansion( double * value, int samples)
{
bool result = false;
double average = 0;
// Get the image from the camera
- result = Dilatometer_GetImage();
+ result = Camera_GetImage( 0, 1600, 1200 ,&g_srcRGB); // Get a 1600x1200 image and place it into src
+
// If an error occured when capturing image then return
if (!result)
return result;
-
+
// Apply the Canny Edge theorem to the image
CannyThreshold();
}
int sample_height;
- int num_edges = 0; // Number of edges. if each sample location has an edge, then num_edges = samples
+ int num_edges = 0; // Number of edges found. if each sample location has an edge, then num_edges = samples
for (int i=0; i<samples; i++)
{
}
if (num_edges > 0)
average /= num_edges;
+ else
+ return result; // As no edges were found
if( average > 0)
{
- result = true; //Successfully found an edge
- *value = average;
+ result = true; // Successfully found an edge
+ // If the experiment has already been initialised
+ if( lastPosition > 0)
+ {
+ // Find the rate of expansion and convert to mm. Will give a negative result for compression.
+ *value = (average - lastPosition) * SCALE;
+ lastPosition = average; // Current position now becomes the last position
+ }
}
return result;
}
*/
bool Dilatometer_Read(int id, double * value)
{
- bool result = Dilatometer_GetEdge(value, SAMPLES);
+ bool result = Dilatometer_GetExpansion(value, SAMPLES);
return result;
}
{
// Make an initial reading (will allocate memory the first time only).
double val;
- Dilatometer_GetEdge(&val, 1);
- return true;
+ lastPosition = 0; // Reset the last position
+ bool result = Dilatometer_GetExpansion(&val, 1);
+ return result;
}
// Overlays a line over the given edge position