在我的摄像头打开时检测到人脸

Posted 2023-03-16

【中文标题】在我的摄像头打开时检测到人脸

【英文标题】：Detect a face while my cam is open

【发布时间】：2018-01-23 02:13:51

【问题描述】：

我需要构建一个只有摄像头视图的应用程序，它应该检测到我的摄像头正在看脸，谁能指出我正确的方向？ 我已经构建了可以检测图像上的人脸的东西，但我需要使用摄像头，这是我到目前为止所做的：

- (void)viewDidLoad 
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    NSString *path = [[NSBundle mainBundle] pathForResource:@"picture" ofType:@"JPG"];
    NSURL *url = [NSURL fileURLWithPath:path];

    CIContext *context = [CIContext contextWithOptions:nil];

    CIImage *image = [CIImage imageWithContentsOfURL:url];

    NSDictionary *options = @CIDetectorAccuracy: CIDetectorAccuracyHigh;

    CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeFace context:context options:options];

    NSArray *features = [detector featuresInImage:image];

我做了以下事情：

-(void)viewWillAppear:(BOOL)animated
    _session = [[AVCaptureSession alloc] init];
    [_session setSessionPreset:AVCaptureSessionPresetPhoto];

    AVCaptureDevice *inputDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

    NSError *error;
    AVCaptureDeviceInput *deviceInput = [AVCaptureDeviceInput deviceInputWithDevice:inputDevice error:&error];

    if([_session canAddInput:deviceInput])
        [_session addInput:deviceInput];
    

    AVCaptureVideoPreviewLayer *previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:_session];
    [previewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
    CALayer *rootLayer = [[self view] layer];
    [rootLayer setMasksToBounds:YES];

    CGRect frame = self.frameCapture.frame;
    [previewLayer setFrame:frame];

    [rootLayer insertSublayer:previewLayer atIndex:0];
    [_session startRunning];



-(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
    for(AVMetadataObject *metadataObject in metadataObjects) 
        if([metadataObject.type isEqualToString:AVMetadataObjectTypeFace]) 

           _faceDetectedLabel.text = @"face detected";
        
    

但它仍然没有检测到任何面孔，我做错了什么吗？

【问题讨论】：

搜索 AVCaptureSession。

【参考方案1】：

您应该在获得一些数据之前添加元数据输出。

AVCaptureMetadataOutput *metadataOutput = [[AVCaptureMetadataOutput alloc] init];
// create a serial queue to handle metadata output
dispatch_queue_t metadataQueueOutput = dispatch_queue_create("com.YourAppName.metaDataQueue.OutputQueue", DISPATCH_QUEUE_SERIAL);
[metadataOutput setMetadataObjectsDelegate:self queue:metadataQueueOutput];
if ([_session canAddOutput:metadataOutput]) 
    [strongSelf.session addOutput:metadataOutput];

// set object types that you are interested, then you should not check type in output callback
metadataOutput.metadataObjectTypes = @[AVMetadataObjectTypeFace];

应该可以。如果有请告诉我