CIFaceFeature只检测到一张脸

Question

问题是我的代码只适用于一张脸。如果我拍一张两张脸的照片，它就不会检测到第二张，而且两张以上的照片也是一样的。这是我的代码：

if let inputImage = imageView.image {
        let ciImage = CIImage(CGImage: inputImage.CGImage!)

        let options = [CIDetectorAccuracy: CIDetectorAccuracyHigh]
        let faceDetector = CIDetector(ofType: CIDetectorTypeFace, context: nil, options: options)

        let faces = faceDetector.featuresInImage(ciImage)

        if let face = faces.first as? CIFaceFeature {
            print("Found face at \(face.bounds)")

            if face.hasLeftEyePosition {
                print("Found left eye at \(face.leftEyePosition)")
            }

            if face.hasRightEyePosition {
                print("Found right eye at \(face.rightEyePosition)")
            }

            if face.hasMouthPosition {
                print("Found mouth at \(face.mouthPosition)")
            }
        }
        print("\(faces.count)")
    }

Answer 1

你的问题是你只在第一张脸上找到了，正因为如此：

if let face = faces.first as? CIFaceFeature {

例如，您可以使用一个循环并对数组进行迭代，如下所示：

for item in faces {
    if let face = item as? CIFaceFeature {
        print("Found face at \(face.bounds)")

        if face.hasLeftEyePosition {
            print("Found left eye at \(face.leftEyePosition)")
        }

        if face.hasRightEyePosition {
            print("Found right eye at \(face.rightEyePosition)")
        }

        if face.hasMouthPosition {
            print("Found mouth at \(face.mouthPosition)")
        }
    }
}

或者像这样，稍微好一点：

if let faces = faceDetector.featuresInImage(ciImage) as? [CIFaceFeature] {
    for face in faces {
        print("Found face at \(face.bounds)")

        if face.hasLeftEyePosition {
            print("Found left eye at \(face.leftEyePosition)")
        }

        if face.hasRightEyePosition {
            print("Found right eye at \(face.rightEyePosition)")
        }

        if face.hasMouthPosition {
            print("Found mouth at \(face.mouthPosition)")
        }
    }
}