making separate IplImage to hold mirrored image. this avoids flickering

[ozzloy@gmail.com/oble] / hello-world.cpp

//use the camera to aid the decision to sleep.
//Copyright 2009 Daniel Watson
/*
    This file is part of oble.

    oble is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    oble is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with oble.  If not, see <http://www.gnu.org/licenses/>.

 */
#include <cv.h>
#include <highgui.h>
#include <stdio.h>

// argument for cvFlip(src, dest, FLIP_TYPE)
#define VERTICAL_FLIP 1

CvHaarClassifierCascade* load_object_detector(const char* cascade_path)
{
	return (CvHaarClassifierCascade*)cvLoad(cascade_path);
}

void detect_and_draw_objects(IplImage* image,
		CvHaarClassifierCascade* cascade,
		int do_pyramids)
{
	IplImage* small_image = image;
	CvMemStorage* storage = cvCreateMemStorage(0);
	CvSeq* faces;
	int i, scale = 1;

	/* if the flag is specified, down-scale the input image to get a
		 performance boost w/o loosing quality (perhaps) */
	if(do_pyramids)
	{
		small_image = cvCreateImage(cvSize(image->width/2,image->height/2),
				IPL_DEPTH_8U, 3);
		cvPyrDown(image, small_image, CV_GAUSSIAN_5x5);
		scale = 2;
	}

	/* use the fastest variant */
	faces = cvHaarDetectObjects(small_image, cascade, storage, 1.2, 2,
			CV_HAAR_DO_CANNY_PRUNING);

	/* draw all the rectangles */
	for(i = 0; i < faces->total; i++)
	{
		/* extract the rectangles only */
		CvRect face = *(CvRect*)cvGetSeqElem(faces, i);
		CvPoint upperLeft = cvPoint(face.x*scale,face.y*scale);
		CvPoint bottomRight = cvPoint((face.x+face.width)*scale,
				(face.y+face.height)*scale);
		cvRectangle(image, upperLeft, bottomRight, CV_RGB(255,0,0), 3);
	}

	if(small_image != image)
		cvReleaseImage(&small_image);
	cvReleaseMemStorage(&storage);
}

// A Simple Camera Capture Framework.
int main(int argc, char** argv)
{
	CvHaarClassifierCascade* cascade = load_object_detector(argv[1]);

	CvCapture* capture = cvCaptureFromCAM(CV_CAP_ANY);
	if(!capture) {
		fprintf(stderr, "ERROR: capture is NULL \n");
		getchar();
		return -1;
	}

	// Create a window in which the captured images will be presented
	cvNamedWindow("mywindow", CV_WINDOW_AUTOSIZE);

	IplImage* frame = cvQueryFrame(capture);
	if(!frame) {
		fprintf(stderr, "ERROR: frame is null...\n");
		getchar();
		return -1;
	}
	IplImage* flipped =
		cvCreateImage(cvGetSize(frame), frame->depth, frame->nChannels);
	// Show the image captured from the camera in the window and repeat
	while(1) {
		// Get one frame
		frame = cvQueryFrame(capture);
		if(!frame) {
			fprintf(stderr, "ERROR: frame is null...\n");
			getchar();
			break;
		}

		//flip the image so displayed right/left corresponds to physical right/left
		cvFlip(frame, flipped, VERTICAL_FLIP);

		detect_and_draw_objects(flipped, cascade, 1);
		cvShowImage("mywindow", flipped);
		// Do not release the frame!

		//If ESC key pressed, Key=0x10001B under OpenCV 0.9.7(linux version),
		//remove higher bits using AND operator
		if((cvWaitKey(10) & 255) == 27) break;
	}

	// Release the capture device housekeeping
	cvReleaseCapture(&capture);
	cvDestroyWindow("mywindow");
	cvReleaseImage(&flipped);
	return 0;
}