由于缩放无法使用ImageView进行人脸检测和缩放？

再一次，我很接近，但是没有香蕉。

我正在尝试遵循一些有关面部识别的教程。几乎有以下代码，但我认为它在缩放和UIImageView在脸部周围放置边框方面缺少一些东西。

我在“照片库”中的照片大小各异（出于某些无法解释的原因），因此我在想象中，他们CIDetector正在寻找面孔，正在应用CGAffineTransforms等，然后尝试将其放置在中UIImageView。但是，从图像（也可以从下面看到）可以看出，它没有被绘制在正确的位置。

的UIImageView尺寸为280x500，并设置为“填充比例”。

弄清楚正在发生的事情的任何帮助都会很棒！

-(void)detectFaces {

    CIContext *context = [CIContext contextWithOptions:nil];
    CIImage *image = [CIImage imageWithCGImage:_imagePhotoChosen.image.CGImage options:nil];
    CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeFace context:context options:@{CIDetectorAccuracy : CIDetectorAccuracyHigh}];
    CGAffineTransform transform = CGAffineTransformMakeScale(1, -1);
    transform = CGAffineTransformTranslate(transform, 0, -_imagePhotoChosen.image.size.height);
    NSArray *features = [detector featuresInImage:image];
    NSLog(@"I have found %lu faces", (long unsigned)features.count);
    for (CIFaceFeature *faceFeature in features)
    {   
        const CGRect faceRect = CGRectApplyAffineTransform(faceFeature.bounds, transform);
        NSLog(@"I have the original frame as: %@", NSStringFromCGRect(faceRect));
        const CGFloat scaleWidth = _imagePhotoChosen.frame.size.width/_imagePhotoChosen.image.size.width;
        const CGFloat scaleHeight = _imagePhotoChosen.frame.size.height/_imagePhotoChosen.image.size.height;

        CGRect faceFrame = CGRectMake(faceRect.origin.x * scaleWidth, faceRect.origin.y * scaleHeight, faceRect.size.width * scaleWidth, faceRect.size.height * scaleHeight);

        UIView *faceView = [[UIView alloc] initWithFrame:faceFrame];
        NSLog(@"I have the bounds as: %@", NSStringFromCGRect(faceFrame));
        faceView.layer.borderColor = [[UIColor redColor] CGColor];
        faceView.layer.borderWidth = 1.0f;

        [self.view addSubview:faceView];
    }

}

-(void) imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{

    _imagePhotoChosen.image = info[UIImagePickerControllerOriginalImage];
    //[_imagePhotoChosen sizeToFit];

    [self.view addSubview:_viewChosenPhoto];
    [picker dismissViewControllerAnimated:YES completion:nil];
    [self detectFaces];

}

我一直在尝试解决数学错误的问题，所以我留在NSLog语句中，但是似乎看不出来是不是！而且我也是数学老师...

再次感谢您为我指明正确方向所做的一切。

更新资料

响应人们想要知道我如何解决的问题……这对我来说确实是一个愚蠢的错误。

我正在将子视图添加到主窗口，而不是添加到UIImageView。因此，我删除了这一行：

[self.view addSubview:faceView];

并替换为：

[_imagePhotoChosen addSubview:faceView];

这样就可以将框架放置在正确的位置。公认的解决方案为我提供了线索！因此，更新后的代码（从那时起，我继续前进了一点：

-(void)detectFaces:(UIImage *)selectedImage {

    _imagePhotoChosen.image = selectedImage;

    CIImage *image = [CIImage imageWithCGImage:selectedImage.CGImage options:nil];

    CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeFace context:nil options:@{CIDetectorAccuracy : CIDetectorAccuracyHigh}];
    CGAffineTransform transform = CGAffineTransformMakeScale(1, -1);
    transform = CGAffineTransformTranslate(transform, 0, -selectedImage.size.height);
    NSArray *features = [detector featuresInImage:image];
    int i = 0;
    for (CIFaceFeature *faceFeature in features)
    {

        const CGRect faceRect = CGRectApplyAffineTransform(faceFeature.bounds, transform);

        const CGFloat scaleWidth = _imagePhotoChosen.frame.size.width/_imagePhotoChosen.image.size.width;
        const CGFloat scaleHeight = _imagePhotoChosen.frame.size.height/_imagePhotoChosen.image.size.height;

        CGRect faceFrame = CGRectMake(faceRect.origin.x * scaleWidth, faceRect.origin.y * scaleHeight, faceRect.size.width * scaleWidth, faceRect.size.height * scaleHeight);

        UIView *faceView = [[UIView alloc] initWithFrame:faceFrame];
        faceView.layer.borderColor = [[UIColor redColor] CGColor];
        faceView.layer.borderWidth = 1.0f;
        faceView.tag = i;

        UITapGestureRecognizer *selectPhotoTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(selectPhoto)];
        selectPhotoTap.numberOfTapsRequired = 1;
        selectPhotoTap.numberOfTouchesRequired = 1;
        [faceView addGestureRecognizer:selectPhotoTap];

        [_imagePhotoChosen addSubview:faceView];
        i++;
    }

}