iOS人脸识别

人脸识别的几种实现方式

Core Image 静态识别

AVFoundation 动态识别

CoreImage和AVFoundation Demo

OPENCV

OpenCV 是一个 C++ 的 API。

集成 OpenCV 的常见错误

报错1：’opencv2/highgui/cap_ios.h’ file not found
解决：其在3.2.0版中已经移到videoio文件夹下，所以需要把 #import <opencv2/highgui/cap_ios.h> 改为 #import <opencv2/videoio/cap_ios.h>。
报错2：enum { NO, GAIN, GAIN_BLOCKS }; Expected identifier
只要把NO修改成 NO_EXPOSURE_COMPENSATOR 或 NO_EXPOSURE_COMPENSATOR = 0
1
2
// enum { NO, GAIN, GAIN_BLOCKS };
enum { NO_EXPOSURE_COMPENSATOR = 0, GAIN, GAIN_BLOCKS };
设置OC与C++混合编译：Build Settings -> Compile Source As：Objective-C++。

OpenCV Demo

Vision

Apple 在 WWDC 2017 伴随iOS 11推出的基于CoreML的图像识别框架。

- (void)beginRecognize{
    __block NSError *error;
    // 创建处理requestHandler
    VNImageRequestHandler *handler = [[VNImageRequestHandler alloc] initWithCIImage:[[CIImage alloc] initWithImage:image] options:@{}];
    VNImageBasedRequest *request = [[VNImageBasedRequest alloc] init];
    request = [[VNDetectFaceLandmarksRequest alloc] initWithCompletionHandler:^(VNRequest * _Nonnull request, NSError * _Nullable error) {
        NSArray *vnobservations = request.results;

        if (vnobservations.count<=0) {

        UIAlertController *alertContrller = [UIAlertController alertControllerWithTitle:@"No face detected!" message:@"Sorry, we are NOT able to detect any face in this photo!" preferredStyle:UIAlertControllerStyleAlert];
        UIAlertAction *confirmAction = [UIAlertAction actionWithTitle:@"Confirm" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        
        }];
        [alertContrller addAction:confirmAction];
        [self presentViewController:alertContrller animated:YES completion:nil];

        }else{
            //...
        }

    }];

    request.preferBackgroundProcessing = YES;
    // 发送识别请求 在后台执行 在更新UI的时候记得切换到主线程
    //    dispatch_async(dispatch_get_main_queue(), ^{
    //        [handler performRequests:@[requset] error:&error];
    //    });
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        [handler performRequests:@[request] error:&error];
    });

    if (error) {
    NSLog(@"%@",error.localizedDescription);
    }
}

第三方

讯飞，腾讯，百度，七牛云，美摄，Amazon recognition,dlib，Face++。