编辑 发现此代码有助于前置摄像头图像http://blog.logichigh.com/2008/06/05/uiimage-fix/
希望其他人有类似的问题，可以帮助我。尚未找到解决方案。 （它可能看起来有点长，但只是一堆帮助代码）
我正在使用ios人脸检测器对相机（正面和背面）获取的图像以及图库中的图像（我正在使用UIImagePicker）进行相机拍摄和图像选择来自画廊 - 没有使用avfoundation来拍摄像squarecam演示一样的照片）
我正在弄乱检测的坐标（如果有的话），所以我写了一个简短的调试方法来获取面的边界以及在它们上面绘制正方形的实用程序，我想检查哪个检测器工作的方向：
#define RECTBOX(R) [NSValue valueWithCGRect:R]
- (NSArray *)detectFaces:(UIImage *)inputimage
{
_detector = \[CIDetector detectorOfType:CIDetectorTypeFace context:nil options:\[NSDictionary dictionaryWithObject:CIDetectorAccuracyLow forKey:CIDetectorAccuracy\]\];
NSNumber *orientation = \[NSNumber numberWithInt:\[inputimage imageOrientation\]\]; // i also saw code where they add +1 to the orientation
NSDictionary *imageOptions = \[NSDictionary dictionaryWithObject:orientation forKey:CIDetectorImageOrientation\];
CIImage* ciimage = \[CIImage imageWithCGImage:inputimage.CGImage options:imageOptions\];
// try like this first
// NSArray* features = \[self.detector featuresInImage:ciimage options:imageOptions\];
// if not working go on to this (trying all orientations)
NSArray* features;
int exif;
// ios face detector. trying all of the orientations
for (exif = 1; exif <= 8 ; exif++)
{
NSNumber *orientation = \[NSNumber numberWithInt:exif\];
NSDictionary *imageOptions = \[NSDictionary dictionaryWithObject:orientation forKey:CIDetectorImageOrientation\];
NSTimeInterval start = \[NSDate timeIntervalSinceReferenceDate\];
features = \[self.detector featuresInImage:ciimage options:imageOptions\];
if (features.count > 0)
{
NSString *str = \[NSString stringWithFormat:@"found faces using exif %d",exif\];
\[faceDetection log:str\];
break;
}
NSTimeInterval duration = \[NSDate timeIntervalSinceReferenceDate\] - start;
NSLog(@"faceDetection: facedetection total runtime is %f s",duration);
}
if (features.count > 0)
{
[faceDetection log:@"-I- Found faces with ios face detector"];
for(CIFaceFeature *feature in features)
{
CGRect rect = feature.bounds;
CGRect r = CGRectMake(rect.origin.x,inputimage.size.height - rect.origin.y - rect.size.height,rect.size.width,rect.size.height);
[returnArray addObject:RECTBOX(r)];
}
return returnArray;
} else {
// no faces from iOS face detector. try OpenCV detector
}
[1]
在尝试了大量不同的图片后，我注意到面部检测器的方向与相机图像属性不一致。我从前置摄像头拍了一堆照片 uiimage方向为3（查询imageOrienation）但面部检测器未找到该设置的面。当通过所有exif可能性时，面部检测器最终拾取面部，但是一起使用不同的方向。
！[1]：http://i.stack.imgur.com/D7bkZ.jpg
我该如何解决这个问题？我的代码中有错误吗？
我遇到的另一个问题（但是与面部检测器紧密相关），当面部检测器拾取面部时，但是对于“错误”方向（主要发生在前置摄像头上），UIImage最初使用在uiiimageview中正确显示，但当我绘制正方形叠加层（我在我的应用程序中使用opencv，所以我决定将UIImage转换为cvmat以使用opencv绘制叠加层时）整个图像旋转90度（仅cvmat图像而不是我最初显示的UIImage
我能想到的原因是面部检测器正在弄乱一些缓冲区（上下文？），即UIimage转换为opencv mat正在使用。我该如何分离这些缓冲区？
将uiimage转换为cvmat的代码是（来自某人制作的“着名”UIImage类别）：
-(cv::Mat)CVMat
{
CGColorSpaceRef colorSpace = CGImageGetColorSpace(self.CGImage);
CGFloat cols = self.size.width;
CGFloat rows = self.size.height;
cv::Mat cvMat(rows, cols, CV_8UC4); // 8 bits per component, 4 channels
CGContextRef contextRef = CGBitmapContextCreate(cvMat.data, // Pointer to backing data
cols, // Width of bitmap
rows, // Height of bitmap
8, // Bits per component
cvMat.step[0], // Bytes per row
colorSpace, // Colorspace
kCGImageAlphaNoneSkipLast |
kCGBitmapByteOrderDefault); // Bitmap info flags
CGContextDrawImage(contextRef, CGRectMake(0, 0, cols, rows), self.CGImage);
CGContextRelease(contextRef);
return cvMat;
}
- (id)initWithCVMat:(const cv::Mat&)cvMat
{
NSData *data = [NSData dataWithBytes:cvMat.data length:cvMat.elemSize() * cvMat.total()];
CGColorSpaceRef colorSpace;
if (cvMat.elemSize() == 1)
{
colorSpace = CGColorSpaceCreateDeviceGray();
}
else
{
colorSpace = CGColorSpaceCreateDeviceRGB();
}
CGDataProviderRef provider = CGDataProviderCreateWithCFData((__bridge CFDataRef)data);
CGImageRef imageRef = CGImageCreate(cvMat.cols, // Width
cvMat.rows, // Height
8, // Bits per component
8 * cvMat.elemSize(), // Bits per pixel
cvMat.step[0], // Bytes per row
colorSpace, // Colorspace
kCGImageAlphaNone | kCGBitmapByteOrderDefault, // Bitmap info flags
provider, // CGDataProviderRef
NULL, // Decode
false, // Should interpolate
kCGRenderingIntentDefault); // Intent
self = [self initWithCGImage:imageRef];
CGImageRelease(imageRef);
CGDataProviderRelease(provider);
CGColorSpaceRelease(colorSpace);
return self;
}
-(cv::Mat)CVRgbMat
{
cv::Mat tmpimage = self.CVMat;
cv::Mat image;
cvtColor(tmpimage, image, cv::COLOR_BGRA2BGR);
return image;
}
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)img editingInfo:(NSDictionary *)editInfo {
self.prevImage = img;
// self.previewView.image = img;
NSArray *arr = [[faceDetection sharedFaceDetector] detectFaces:img];
for (id r in arr)
{
CGRect rect = RECTUNBOX(r);
//self.previewView.image = img;
self.previewView.image = [utils drawSquareOnImage:img square:rect];
}
[self.imgPicker dismissModalViewControllerAnimated:YES];
return;
}
答案 0 :(得分：4)
我不认为旋转整堆图像像素并匹配CIFaceFeature是个好主意。你可以想象在旋转方向上重绘是非常沉重的。我有同样的问题，我通过转换CIFaceFeature的坐标系相对于UIImageOrientation来解决它。我使用一些转换方法扩展了CIFaceFeature类，以获得关于UIImage及其UIImageView（或UIView的CALayer）的正确点位置和边界。完整的实施发布在此处：https://gist.github.com/laoyang/5747004。你可以直接使用。
以下是来自CIFaceFeature的点的最基本转换，返回的CGPoint根据图像的方向进行转换：
- (CGPoint) pointForImage:(UIImage*) image fromPoint:(CGPoint) originalPoint {
CGFloat imageWidth = image.size.width;
CGFloat imageHeight = image.size.height;
CGPoint convertedPoint;
switch (image.imageOrientation) {
case UIImageOrientationUp:
convertedPoint.x = originalPoint.x;
convertedPoint.y = imageHeight - originalPoint.y;
break;
case UIImageOrientationDown:
convertedPoint.x = imageWidth - originalPoint.x;
convertedPoint.y = originalPoint.y;
break;
case UIImageOrientationLeft:
convertedPoint.x = imageWidth - originalPoint.y;
convertedPoint.y = imageHeight - originalPoint.x;
break;
case UIImageOrientationRight:
convertedPoint.x = originalPoint.y;
convertedPoint.y = originalPoint.x;
break;
case UIImageOrientationUpMirrored:
convertedPoint.x = imageWidth - originalPoint.x;
convertedPoint.y = imageHeight - originalPoint.y;
break;
case UIImageOrientationDownMirrored:
convertedPoint.x = originalPoint.x;
convertedPoint.y = originalPoint.y;
break;
case UIImageOrientationLeftMirrored:
convertedPoint.x = imageWidth - originalPoint.y;
convertedPoint.y = originalPoint.x;
break;
case UIImageOrientationRightMirrored:
convertedPoint.x = originalPoint.y;
convertedPoint.y = imageHeight - originalPoint.x;
break;
default:
break;
}
return convertedPoint;
}
以下是基于上述转换的类别方法：
// Get converted features with respect to the imageOrientation property
- (CGPoint) leftEyePositionForImage:(UIImage *)image;
- (CGPoint) rightEyePositionForImage:(UIImage *)image;
- (CGPoint) mouthPositionForImage:(UIImage *)image;
- (CGRect) boundsForImage:(UIImage *)image;
// Get normalized features (0-1) with respect to the imageOrientation property
- (CGPoint) normalizedLeftEyePositionForImage:(UIImage *)image;
- (CGPoint) normalizedRightEyePositionForImage:(UIImage *)image;
- (CGPoint) normalizedMouthPositionForImage:(UIImage *)image;
- (CGRect) normalizedBoundsForImage:(UIImage *)image;
// Get feature location inside of a given UIView size with respect to the imageOrientation property
- (CGPoint) leftEyePositionForImage:(UIImage *)image inView:(CGSize)viewSize;
- (CGPoint) rightEyePositionForImage:(UIImage *)image inView:(CGSize)viewSize;
- (CGPoint) mouthPositionForImage:(UIImage *)image inView:(CGSize)viewSize;
- (CGRect) boundsForImage:(UIImage *)image inView:(CGSize)viewSize;
（需要注意的另一件事是从UIImage方向提取面部特征时指定正确的EXIF方向。相当令人困惑......这就是我所做的：
int exifOrientation;
switch (self.image.imageOrientation) {
case UIImageOrientationUp:
exifOrientation = 1;
break;
case UIImageOrientationDown:
exifOrientation = 3;
break;
case UIImageOrientationLeft:
exifOrientation = 8;
break;
case UIImageOrientationRight:
exifOrientation = 6;
break;
case UIImageOrientationUpMirrored:
exifOrientation = 2;
break;
case UIImageOrientationDownMirrored:
exifOrientation = 4;
break;
case UIImageOrientationLeftMirrored:
exifOrientation = 5;
break;
case UIImageOrientationRightMirrored:
exifOrientation = 7;
break;
default:
break;
}
NSDictionary *detectorOptions = @{ CIDetectorAccuracy : CIDetectorAccuracyHigh };
CIDetector *faceDetector = [CIDetector detectorOfType:CIDetectorTypeFace context:nil options:detectorOptions];
NSArray *features = [faceDetector featuresInImage:[CIImage imageWithCGImage:self.image.CGImage]
options:@{CIDetectorImageOrientation:[NSNumber numberWithInt:exifOrientation]}];
）
答案 1 :(得分：0)
iOS 10和Swift 3
您可以查看苹果示例，您可以检测面部或条形码的值以及 Qrcode
https://developer.apple.com/library/content/samplecode/AVCamBarcode/Introduction/Intro.html