iOS开发-CIDetector识别图片中人脸功能

一 CIDetector是什么？

CIDetector是CoreImage框架中提供的一个识别的类，可以对人脸、形状、条码、文本进行识别。

示例代码

// 创建图形上下文
CIContext * context = [CIContext contextWithOptions:nil];
// 创建自定义参数字典
NSDictionary * param = [NSDictionary dictionaryWithObject:CIDetectorAccuracyHigh forKey:CIDetectorAccuracy];
// 创建识别器对象
CIDetector * faceDetector = [CIDetector detectorOfType:CIDetectorTypeFace context:context options:param];

二 CIDetector识别人脸

识别人脸，我们首先设置识别的属性option

NSDictionary *options = @{
            CIDetectorAccuracy:CIDetectorAccuracyHigh, // 设置检测精确度
            CIDetectorEyeBlink:@(YES), // 是否检测眨眼
            CIDetectorTracking:@(YES) // 是否追踪人脸
        };

之后识别图片中的人脸功能

代码如下

#import "SDFaceDetector.h"

@interface SDFaceDetector ()

/// CIDetector 的配置
@property (nonatomic, strong) NSMutableDictionary *detectorOptions;

/// CIDetector
@property (nonatomic, strong) CIDetector *faceDetector;

@end

@implementation SDFaceDetector

- (instancetype)init
{
    self = [super init];
    if (self) {
        
    }
    return self;
}

- (void)detectorFace:(CIImage *)ciimage {
    // 先转换成CGImage
//    CGImageRef cgImg = [image CGImage];
    // 再转换成 CIImage
//    CIImage *ciImage = [CIImage imageWithCGImage:cgImg];
    CIImage *ciImage = ciimage;
    if (!ciimage) {
        return;
    }
    NSArray<CIFeature *> *features = [self.faceDetector featuresInImage:ciImage options:self.detectorOptions];
    
    NSLog(@"features:%@", features);
    
    for (CIFeature *feature in features) {
            if ([feature isKindOfClass:CIFaceFeature.class]) {
                CIFaceFeature *faceFeature = (CIFaceFeature *)feature;
                // 判断是否检测到了嘴巴，是否检测到了左右眼，是否有追踪ID，如果在创建CIDetector 时允许了人脸追踪，则相同的人脸会有相同的trackingID。
                if (faceFeature.hasMouthPosition && faceFeature.hasLeftEyePosition && faceFeature.hasRightEyePosition && faceFeature.hasTrackingID) {
                  // faceFeature.bounds 属性保存了人脸的位置信息。
                 // 处理图像，处理图像的部分，比如裁剪和缩放灰度等，ios原生也能处理，你也可以选择用Opencv处理。
                }
            }
    }
}

#pragma mark - Lazy
- (NSMutableDictionary *)detectorOptions {
    if (!_detectorOptions) {
        NSDictionary *options = @{
            CIDetectorAccuracy:CIDetectorAccuracyHigh, // 设置检测精确度
            CIDetectorEyeBlink:@(YES), // 是否检测眨眼
            CIDetectorTracking:@(YES) // 是否追踪人脸
        };
        _detectorOptions = [NSMutableDictionary dictionaryWithDictionary:options];
    }
    return _detectorOptions;
}

- (CIDetector *)faceDetector {
    if (!_faceDetector) {
        _faceDetector = [CIDetector detectorOfType:CIDetectorTypeFace context: nil options:self.detectorOptions];;
    }
    return _faceDetector;
}

@end