// 得到圖片的尺寸
CIImage *faceImage = [CIImage imageWithCGImage:image.CGImage];
CGSize inputImageSize = [faceImage extent].size;
//將image沿y軸對稱 這個不能少 少了取到的image爲空
CGAffineTransform transform = CGAffineTransformScale(CGAffineTransformIdentity, 1, -1);
//將圖片上移
transform = CGAffineTransformTranslate(transform, 0, -inputImageSize.height);
//取第一張臉去截取
CIFaceFeature *faceFeature = [features firstObject];
//獲取人臉的frame
CGRect faceViewBounds = CGRectApplyAffineTransform(faceFeature.bounds, transform);
UIImage *smallImage = [VideoCaptureView ct_imageFromImage:image inRect:faceViewBounds];
附 裁剪image
+ (UIImage *)imageFromImage:(UIImage *)image inRect:(CGRect)rect{
//截取部分圖片並生成新圖片
CGImageRef sourceImageRef = [image CGImage];
CGImageRef newImageRef = CGImageCreateWithImageInRect(sourceImageRef, rect);
UIImage *newImage = [UIImage imageWithCGImage:newImageRef scale:1 orientation:image.imageOrientation];
return newImage;
}