来自相机的人脸检测iOS答案

【问题标题】：face detection iOS from camera来自相机的人脸检测iOS
【发布时间】：2014-05-25 19:31:49
【问题描述】：

我收到一个图像视图

-(void)imagePickerController:(UIImagePickerController *)picker
didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    NSString *mediaType = info[UIImagePickerControllerMediaType];

    [self dismissViewControllerAnimated:YES completion:nil];

    if ([mediaType isEqualToString:(NSString *)kUTTypeImage]) {
        UIImage *image = info[UIImagePickerControllerOriginalImage];

        //imgvprofileImage.image = image;
        //[self detectForFacesInUIImage:[UIImage imageNamed:@"image00.jpg"]];

        [self detectForFacesInUIImage:image];
    }
    else if ([mediaType isEqualToString:(NSString *)kUTTypeMovie])
    {
        // Code here to support video if enabled
    }
}

当我发送这样的照片时

[self detectForFacesInUIImage:[UIImage imageNamed:@"image00.jpg"]];

检测效果很好并找到了人脸，但是当我使用从相机返回的图像时它不起作用。

 [self detectForFacesInUIImage:image]

这是我用来检测人脸的函数

-(void)detectForFacesInUIImage:(UIImage *)facePicture
{
    CIImage* image = [CIImage imageWithCGImage:facePicture.CGImage];

    CIDetector* detector = [CIDetector detectorOfType:CIDetectorTypeFace context:nil options:[NSDictionary dictionaryWithObject:CIDetectorAccuracyLow forKey:CIDetectorAccuracy]];

    NSArray* features = [detector featuresInImage:image];

    if (features.count == 0) {
        NSLog(@"There is no faces in captured image ") ;
    }

    for(CIFaceFeature* faceObject in features)
    {
        CGRect modifiedFaceBounds = faceObject.bounds;
        modifiedFaceBounds.origin.y = facePicture.size.height-faceObject.bounds.size.height-faceObject.bounds.origin.y;

        [self addSubViewWithFrame:facePicture toRect:modifiedFaceBounds] ;
    }
}

【问题讨论】：

标签： ios objective-c uiimage ios-camera

【解决方案1】：

问题在于图像方向。

不记得我在哪里拿的，但它有效：

- (void) detectForFaces:(CGImageRef)facePicture orientation:(UIImageOrientation)orientation {


    CIImage* image = [CIImage imageWithCGImage:facePicture];

    CIContext *context = [CIContext contextWithOptions:nil];                    // 1
    NSDictionary *opts = @{ CIDetectorAccuracy : CIDetectorAccuracyLow };      // 2
    CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeFace
                                              context:context
                                              options:opts];                    // 3

    int exifOrientation;
    switch (orientation) {
        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;
    }


    opts = @{ CIDetectorImageOrientation :[NSNumber numberWithInt:exifOrientation
                                           ] };

    NSArray *features = [detector featuresInImage:image options:opts];

    if ([features count] > 0) {
        CIFaceFeature *face = [features lastObject];
        NSLog(@"%@", NSStringFromCGRect(face.bounds));
    }
}

使用方法：

UIImage *image = // some image here;
[self detectForFaces:image.CGImage orientation:image.imageOrientation];

【讨论】：

如何获取参数 UIImageOrientation ？
@mohamed UIImage 有属性imageOrientation
UIImage *image = info[UIImagePickerControllerOriginalImage]; [self detectForFaces:image.CGImageorientation:[image get]] 我怎么称呼这是对的？？我没找到房产？？
和之前的检测不准确？？
当我 corp 之前的图像完全是脸部，但现在它根本不准确？？

【解决方案2】：

这里小修正

- (void) detectForFaces:(UIImage *)facePicture orientation:(UIImageOrientation)orientation {


CIImage* image = [CIImage imageWithCGImage:facePicture.CGImage];

CIContext *context = [CIContext contextWithOptions:nil];                    // 1
NSDictionary *opts = @{ CIDetectorAccuracy : CIDetectorAccuracyLow };      // 2
CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeFace
                                          context:context
                                          options:opts];                    // 3

int exifOrientation;
switch (orientation) {
    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;
}


opts = @{ CIDetectorImageOrientation :[NSNumber numberWithInt:exifOrientation
                                       ] };

NSArray *features = [detector featuresInImage:image options:opts];

if ([features count] > 0) {
    CIFaceFeature *face = [features lastObject];
    NSLog(@"%@", NSStringFromCGRect(face.bounds));
}}

UIImage *image = // some image here; [self detectForFaces:image orientation:image.imageOrientation];

只发送图片而不是 image.CGImage 这对我有用

【讨论】：