自帶的較為便捷的人臉圖像識別功能
識別能力較弱译蒂，僅能分辨出圖像中有多少處人像絮缅，不可做人臉圖像對比
//圖像識別能力：可以在CIDetectorAccuracyHigh(較強的處理能力)與CIDetectorAccuracyLow(較弱的處理能力)中選擇搬俊，因為想讓準確度高一些在這里選擇CIDetectorAccuracyHigh
NSDictionary *opts = [NSDictionary dictionaryWithObject: CIDetectorAccuracyHigh forKey:CIDetectorAccuracy];
// 將圖像轉(zhuǎn)換為CIImage
CIImage *faceImage = [CIImage imageWithCGImage:image.CGImage];
CIDetector *faceDetector = [CIDetector detectorOfType:CIDetectorTypeFace context:nil options:opts];
// 識別出人臉數(shù)組
NSArray *features = [faceDetector featuresInImage:faceImage];
