-/**
- * @file dilatometer.c
- * @purpose Implementation of dilatometer related functions
- */
-
-#include "cv.h"
-#include "highgui_c.h"
-#include "dilatometer.h"
-#include <math.h>
-
-// test positions
-static double test_left, test_right;
-
-// Canny Edge algorithm variables
-int blur = 5;
-int lowThreshold = 30;
-int ratio = 3;
-int kernel_size = 3;
-
-/** Buffers for storing image data. **/
-static CvMat * g_srcRGB = NULL; // Source Image
-static CvMat * g_srcGray = NULL; // Gray scale of source image
-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
-
-
-/**
- * Create a test image using left as left edge and right as right edge positions
- */
-void Dilatometer_TestImage()
-{
-
- g_srcRGB = cvCreateMat(480, 640, CV_8UC3);
-
- for( int x = 0; x < 640; ++x)
- {
- for (int y = 0; y < 480; ++y)
- {
- CvScalar s;
- for( int i = 0; i < 3; ++i)
- {
- s.val[i] = 210 + (rand() % 1000) * 1e-0 - (rand() % 1000) * 1e-0;
- // Produce an exponential decay around left edge
- if( x < test_left)
- s.val[i] *= exp( (x - test_left) / 25);
- else if( x < 320)
- s.val[i] *= exp( (test_left - x) / 25);
- // Produce an exponential decay around right edge
- else if( x < test_right)
- s.val[i] *= exp( (x - test_right) / 25);
- else
- s.val[i] *= exp( (test_right - x) / 25);
- }
- cvSet2D(g_srcRGB,y,x,s);
- }
-
- }
- if (g_srcGray == NULL)
- {
- g_srcGray = cvCreateMat(g_srcRGB->rows,g_srcRGB->cols,CV_8UC1);
- }
- cvCvtColor(g_srcRGB,g_srcGray,CV_RGB2GRAY);
-}
-
-/**
- * Cleanup Dilatometer pointers
- */
-void Dilatometer_Cleanup()
-{
- 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)
- cvReleaseMat(&g_srcGray);
- if (g_edges != NULL)
- cvReleaseMat(&g_edges);
-}
-
-/**
- * Get an image from the Dilatometer
- */
-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
- if( g_capture == NULL)
- {
- g_capture = cvCreateCameraCapture(0);
- //If cvCreateCameraCapture returns NULL there is an error with the camera
- if( g_capture == NULL)
- {
- result = false;
- return;
- }
- }
-
- // Get the frame and convert it to CvMat
- frame = cvQueryFrame(g_capture);
- CvMat stub;
- g_srcRGB = cvGetMat(frame,&stub,0,0);
-
- if( g_srcRGB == NULL)
- result = false;
-
- // Convert the image to grayscale
- if (g_srcGray == NULL)
- {
- g_srcGray = cvCreateMat(g_srcRGB->rows,g_srcRGB->cols,CV_8UC1);
- }
-
- cvCvtColor(g_srcRGB,g_srcGray,CV_RGB2GRAY);
-
- return result;
-}
-
-void CannyThreshold()
-{
- if ( g_edges == NULL)
- {
- g_edges = cvCreateMat(g_srcGray->rows,g_srcGray->cols,CV_8UC1);
- }
-
- // Commented out lines are used during testing to show the image to screen, can also save the test images
- //cvShowImage("display", g_srcGray);
- //cvWaitKey(0);
-
- // Reduce noise with a kernel blurxblur. Input the grayscale source image, output to edges. (0's mean it's determined from kernel sizes)
- cvSmooth( g_srcGray, g_edges, CV_GAUSSIAN, blur, blur ,0 ,0 );
-
- //Save the image
- //cvSaveImage("test_blurred.jpg",g_edges,0);
-
- //cvShowImage("display", g_edges);
- //cvWaitKey(0);
-
- // Find the edges in the image
- cvCanny( g_edges, g_edges, lowThreshold, lowThreshold*ratio, kernel_size );
-
- //Save the image
- //cvSaveImage("test_edge.jpg",g_edges,0);
-
- //cvShowImage("display", g_edges);
- //cvWaitKey(0);
-
-}
-
- /**
- * Read the dilatometer image. The value changed will correspond to the new location of the edge.
- * @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 result = false;
- double average = 0;
- // Get the image from the camera
- result = Dilatometer_GetImage();
- // If an error occured when capturing image then return
- if (!result)
- return result;
-
- // Apply the Canny Edge theorem to the image
- CannyThreshold();
-
- int width = g_edges->cols;
- int height = g_edges->rows;
-
- // If the number of samples is greater than the image height, sample every row
- if( samples > height)
- {
- samples = height;
- }
-
- int sample_height;
- int num_edges = 0; // Number of edges. if each sample location has an edge, then num_edges = samples
-
- for (int i=0; i<samples; i++)
- {
- // Determine the position in the rows to find the edges.
- // This will give you a number of evenly spaced samples
- sample_height = ceil(height * (i + 1) / samples) -1;
-
- // Need to go through each pixel of a row and find all the locations of a line. If there is more than one pixel, average it. note this only works if the canny edge algorithm returns lines about the actual line (no outliers).
-
- int edge_location=0;
- int num=0;
- for ( int col = 0; col < width; col++)
- {
- // Count the number of points
- // Get the threshold of the pixel at the current location
- CvScalar value = cvGet2D(g_edges, sample_height, col);
- if( value.val[0]> THRES)
- {
- edge_location += col;
- num++;
- }
- }
- if( num > 0)
- {
- average += ( edge_location / num );
- num_edges++;
- }
- }
- if (num_edges > 0)
- average /= num_edges;
-
- if( average > 0)
- {
- result = true; //Successfully found an edge
- *value = average;
- }
- return result;
-}
-
- /**
- * Read the dilatometer image. The value changed will correspond to the new location of the edge.
- * @param val - Will store the read value if successful
- * @returns true on successful read
- */
-bool Dilatometer_Read( double * value)
-{
- bool result = Dilatometer_GetEdge(value, SAMPLES);
- return result;
-}
-
-/**
- * Initialise the dilatometer
- */
-void Dilatometer_Init()
-{
- // Make an initial reading (will allocate memory the first time only).
- double val;
- Dilatometer_GetEdge(&val, 1);
-}
-
-// Overlays a line over the given edge position
-void Draw_Edge(double edge)
-{
- CvScalar value;
- value.val[0]=244;
- for( int i = 0; i < g_srcGray->rows; i++)
- {
- cvSet2D(g_edges,i,edge,value);
- }
- cvShowImage("display", g_edges);
- cvWaitKey(0);
- //cvSaveImage("test_edge_avg.jpg",g_edges,0);
-}
-
-/* // Test algorithm
-static void Dilatometer_GetImageTest( )
-{
- //Generates Test image
- //Dilatometer_TestImage();
-
- //Load Test image
- g_srcGray = cvLoadImageM ("testimage4.jpg",CV_LOAD_IMAGE_GRAYSCALE );
-}*/
-
-/**
- * For testing purposes
- */
-int main(int argc, char ** argv)
-{
- //cvNamedWindow( "display", CV_WINDOW_AUTOSIZE );// Create a window for display.
- //gettimeofday(&start, NULL);
- test_left = 100;
- test_right = 500;
- Dilatometer_Init();
-
- cvNamedWindow( "display", CV_WINDOW_AUTOSIZE);
- //double width;
-
- double edge;
- Dilatometer_GetEdge(&edge,20000);
- //For testing purposes, overlay the given average line over the image
- //Draw_Edge(edge);
-
- cvDestroyWindow("display");
-
- Dilatometer_Cleanup();
-}
-