- (BOOL)checkImageHasFace
{
    BOOL hasFace = NO;
    CIImage *begingImage = [[CIImage alloc] initWithImage:_postImage];
    //创建CIDetector对象，options使用NSDictionary设置采用高品质还是低品质，这里使用低品质。
    CIDetector *detector = [CIDetector detectorOfType:CIDetectorTypeFace context:nil options:[NSDictionary dictionaryWithObject:CIDetectorAccuracyLow forKey:CIDetectorAccuracy]];
    //返回数组中包含图片脸部特征信息
    NSArray *faceFeatures = [detector featuresInImage:begingImage];
    for (CIFaceFeature *faceFeature in faceFeatures) {
        //左眼位置、右眼位置和嘴的位置
        if (faceFeature.hasLeftEyePosition&&faceFeature.hasRightEyePosition&&faceFeature.hasMouthPosition) {
            hasFace = YES;
        }
    }
    return hasFace;
}