OpenCV Display image and transforms

#include "chapter2.h"

void display_image(char** argv, int task)
{
	// Load the image passed by the user
	IplImage *pImage = cvLoadImage(argv[1]);
	// Create a window using the HighGUI library. 
	// Give the window a title and assign a name to the window for future reference.
	// Setting to autosize to take the size of image. If set to zero image will be scaled to fit window
	cvNamedWindow("Original Image", CV_WINDOW_AUTOSIZE ); 
	// Now we can use the image pointer and the display window to show the image
	cvShowImage("Original Image" , pImage);
	IplImage* pOut = NULL;


	switch (task)
	{
	case APPLY_GAUSS:
		pOut = smooth_display(pImage);
		break;
	case APPLY_PYR_DOWN:
		pOut = apply_pyr_dow(pImage);
		break;
	case APPLY_CANNY:
		pOut = apply_canny(pImage, 10, 100, 3);
		if(pOut == NULL)
		{
			cout<<"Please feed greyscale image! the number of channels:"<<pImage->nChannels<<endl;
		}
		break;

	default:
		cout <<"Please enter a valid task choice"<<endl;
		break;
	}
	if (pOut)
	{
		cvNamedWindow("Transformed output", CV_WINDOW_AUTOSIZE ); 
		// Now we can use the image pointer and the display window to show the image
		cvShowImage("Transformed output" , pOut);
	}
	cvWaitKey();
	// Free allocated space for image
	cvReleaseImage(&pImage);
	if (pOut)
	{
		cvReleaseImage(&pOut);
		cvDestroyWindow("Transformed output");
	}
	// Destroy the window you created
	cvDestroyWindow("Original Image");


}

IplImage* smooth_display(IplImage* pImage)
{
	IplImage* pImageSmooth = NULL;

	// Create and image of the same size of 3 channels with 8bits/channel
	pImageSmooth = cvCreateImage(cvGetSize(pImage),
				     IPL_DEPTH_8U,3);
	// Call smoothing function to apply a 3x3 gaussian filter centered at each pixel
	cvSmooth(pImage,pImageSmooth,CV_GAUSSIAN,3,3);

	return pImageSmooth;
	
}


IplImage* apply_pyr_dow(IplImage* pImage)
{
	IplImage* pOut = cvCreateImage(cvSize(pImage->width/2,pImage->height/2),pImage->depth,pImage->nChannels);
	cvPyrDown(pImage,pOut,CV_GAUSSIAN_5x5);
	return pOut;
}

IplImage* apply_canny(IplImage* pImage, double lowThresh, double highThresh, double aperture)
{
	/*if (pImage->nChannels != 1)return NULL; /*For some reason even greyscale images ended up with 3 channels
	need to investigate futher when I have time*/
	IplImage* pOut = cvCreateImage(cvGetSize(pImage),
					IPL_DEPTH_8U,1);
	cvCanny(pImage, pOut, lowThresh, highThresh, aperture);
	return pOut;
}

/*
void cvSmooth(const CvArr* src, CvArr* dst, int smoothtype=CV_GAUSSIAN, int size1=3, int size2=0, double sigma1=0, double sigma2=0 )
	
src – The source image
dst – The destination image
smoothtype –
Type of the smoothing:

CV_BLUR_NO_SCALE 
CV_BLUR
CV_GAUSSIAN 
CV_MEDIAN
CV_BILATERAL 
size1 – The first parameter of the smoothing operation, the aperture width. Must be a positive odd number (1, 3, 5, ...)
size2 – The second parameter of the smoothing operation, the aperture height. Ignored by CV_MEDIAN and CV_BILATERAL methods. 
In the case of simple scaled/non-scaled and Gaussian blur if size2 is zero, it is set to size1 .
Otherwise it must be a positive odd number.
*/