Crop circular or elliptical image from original UIImage
- by vikas ojha
I am working on openCV for detecting the face .I want face to get cropped once its detected.Till now I got the face and have marked the rect/ellipse around it on iPhone.
Please help me out in cropping the face in circular/elliptical pattern
(UIImage *) opencvFaceDetect:(UIImage *)originalImage
{
cvSetErrMode(CV_ErrModeParent);
IplImage *image = [self CreateIplImageFromUIImage:originalImage];
// Scaling down
/*
Creates IPL image (header and data) ----------------cvCreateImage
CVAPI(IplImage*) cvCreateImage( CvSize size, int depth, int channels );
*/
IplImage *small_image = cvCreateImage(cvSize(image->width/2,image->height/2),
IPL_DEPTH_8U, 3);
/*SMOOTHES DOWN THYE GUASSIAN SURFACE--------:cvPyrDown*/
cvPyrDown(image, small_image, CV_GAUSSIAN_5x5);
int scale = 2;
// Load XML
NSString *path = [[NSBundle mainBundle] pathForResource:@"haarcascade_frontalface_default" ofType:@"xml"];
CvHaarClassifierCascade* cascade = (CvHaarClassifierCascade*)cvLoad([path cStringUsingEncoding:NSASCIIStringEncoding], NULL, NULL, NULL);
// Check whether the cascade has loaded successfully. Else report and error and quit
if( !cascade )
{
NSLog(@"ERROR: Could not load classifier cascade\n");
//return;
}
//Allocate the Memory storage
CvMemStorage* storage = cvCreateMemStorage(0);
// Clear the memory storage which was used before
cvClearMemStorage( storage );
CGColorSpaceRef colorSpace;
CGContextRef contextRef;
CGRect face_rect;
// Find whether the cascade is loaded, to find the faces. If yes, then:
if( cascade )
{
CvSeq* faces = cvHaarDetectObjects(small_image, cascade, storage, 1.1f, 3, 0, cvSize(20, 20));
cvReleaseImage(&small_image);
// Create canvas to show the results
CGImageRef imageRef = originalImage.CGImage;
colorSpace = CGColorSpaceCreateDeviceRGB();
contextRef = CGBitmapContextCreate(NULL, originalImage.size.width, originalImage.size.height, 8, originalImage.size.width * 4,
colorSpace, kCGImageAlphaPremultipliedLast|kCGBitmapByteOrderDefault);
//VIKAS
CGContextDrawImage(contextRef, CGRectMake(0, 0, originalImage.size.width, originalImage.size.height), imageRef);
CGContextSetLineWidth(contextRef, 4);
CGContextSetRGBStrokeColor(contextRef, 1.0, 1.0, 1.0, 0.5);
// Draw results on the iamge:Draw all components of face in the form of small rectangles
// Loop the number of faces found.
for(int i = 0; i < faces->total; i++)
{
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
// Calc the rect of faces
// Create a new rectangle for drawing the face
CvRect cvrect = *(CvRect*)cvGetSeqElem(faces, i);
// CGRect face_rect = CGContextConvertRectToDeviceSpace(contextRef,
// CGRectMake(cvrect.x * scale, cvrect.y * scale, cvrect.width * scale, cvrect.height * scale));
face_rect = CGContextConvertRectToDeviceSpace(contextRef,
CGRectMake(cvrect.x*scale, cvrect.y , cvrect.width*scale , cvrect.height*scale*1.25
));
facedetectapp=(FaceDetectAppDelegate *)[[UIApplication sharedApplication]delegate];
facedetectapp.grabcropcoordrect=face_rect;
NSLog(@" FACE off %f %f %f %f",facedetectapp.grabcropcoordrect.origin.x,facedetectapp.grabcropcoordrect.origin.y,facedetectapp.grabcropcoordrect.size.width,facedetectapp.grabcropcoordrect.size.height);
CGContextStrokeRect(contextRef, face_rect);
//CGContextFillEllipseInRect(contextRef,face_rect);
CGContextStrokeEllipseInRect(contextRef,face_rect);
[pool release];
}
}
CGImageRef imageRef = CGImageCreateWithImageInRect([originalImage CGImage],face_rect);
UIImage *returnImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
CGContextRelease(contextRef);
CGColorSpaceRelease(colorSpace);
cvReleaseMemStorage(&storage);
cvReleaseHaarClassifierCascade(&cascade);
return returnImage;
}
}
Thanks
Vikas
