AI(二)：人脸识别

微软提供的人脸识别服务可检测图片中一个或者多个人脸，并为人脸标记出边框，同时还可获得基于机器学习技术做出的面部特征预测。可支持的人脸功能有：年龄、性别、头部姿态、微笑检测、胡须检测以及27个面部重要特征点位置等。FaceAPI 提供两个主要功能: 人脸检测和识别

目录：

申请subscription key
示例效果
开发示例
AForge.Net

申请订阅号

申请试用subscription key，地址 https://www.microsoft.com/cognitive-services/en-us/sign-up
收费信息如下：

示例效果

winform示例版，调用微软提供的SDK，见下面介绍
微信集成版, 如下图，开发过程中使用 http 直接调用

开发过程

参见：https://www.azure.cn/cognitive-services/en-us/face-api/documentation/get-started-with-face-api/GettingStartedwithFaceAPIinCSharp
在VS工程的NuGet Package Manager 管理窗口，程序包源:nuget.org, 搜索 Microsoft.ProjectOxford.Face ，进行安装

sdk调用示例代码：图片转byte[]

 using (Stream s = new MemoryStream(bytes))
            {
                var requiredFaceAttributes = new FaceAttributeType[] {
                    FaceAttributeType.Age,
                    FaceAttributeType.Gender,
                    FaceAttributeType.Smile,
                    FaceAttributeType.FacialHair,
                    FaceAttributeType.HeadPose,
                    FaceAttributeType.Glasses
                };
                var faces = await Utils.FaceClient.DetectAsync(s,
                    returnFaceLandmarks: true,
                    returnFaceAttributes: requiredFaceAttributes);
          }

也可直接使用http请求，参见：https://dev.projectoxford.ai/docs/services/563879b61984550e40cbbe8d/operations/563879b61984550f30395236
参数信息如下：

http post 示例代码：

string URL = "你图片的url";

            var client = new HttpClient();
            var queryString = HttpUtility.ParseQueryString(string.Empty);

            // Request headers
            client.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", "你申请的key");

            // Request parameters
            queryString["returnFaceId"] = "true";
            queryString["returnFaceLandmarks"] = "false";
            queryString["returnFaceAttributes"] = "age,gender,smile";
            var uri = "https://api.projectoxford.ai/face/v1.0/detect?" + queryString;

            HttpResponseMessage response;
            byte[] byteData = Encoding.UTF8.GetBytes("{"url":"" + URL + ""}");

            using (var content = new ByteArrayContent(byteData))
            {
                content.Headers.ContentType = new MediaTypeHeaderValue("application/json");

                var task = client.PostAsync(uri, content);
                response = task.Result;

                var task1 = response.Content.ReadAsStringAsync();
                string JSON = task1.Result;
            }

人脸识别http参数如下：（注意：要识别出人脸的身份，你必须先定义person，参见 personGroup 、Person介绍 https://www.azure.cn/cognitive-services/en-us/face-api/documentation/face-api-how-to-topics/howtoidentifyfacesinimage）

示例代码

var client = new HttpClient();
            var queryString = HttpUtility.ParseQueryString(string.Empty);
            client.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", "XXX");
            var uri = "https://api.projectoxford.ai/face/v1.0/identify ";
            HttpResponseMessage response;
            byte[] byteData = Encoding.UTF8.GetBytes("{"faceIds":["XXX"],"personGroupId":"XXX","maxNumOfCandidatesReturned":5}");

            using (var content = new ByteArrayContent(byteData))
            {
                content.Headers.ContentType = new MediaTypeHeaderValue("application/json");

                var task = client.PostAsync(uri, content);
                response = task.Result;

                var task1 = response.Content.ReadAsStringAsync();
                string JSON = task1.Result;
            }

根据人脸信息识别出身份后，获取个人信息，参数如下：

示例代码

var client = new HttpClient();
            var queryString = HttpUtility.ParseQueryString(string.Empty);
            client.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", "你申请的key");
            var uri = "https://api.projectoxford.ai/face/v1.0/persongroups/你上传的分组/persons/" + personID;

            var task = client.GetStringAsync(uri);
            var  response = task.Result;
            return JsonConvert.DeserializeObject<Person>(task.Result);

AForge.Net

AForge.Net是一个专门为开发者和研究者基于C#框架设计的，他包括计算机视觉与人工智能，图像处理，神经网络，遗传算法，机器学习，模糊系统，机器人控制等领域, 我主要使用这个类库中的vedio 来启动笔记本摄像头进行图片抓拍
类库下载地址： http://www.aforgenet.com/framework/downloads.html
添加控件：在工具箱中添加AForge.Control，VideoSourcePlayer就是我们要用的控件

示例代码如下：声明变量

FilterInfoCollection videoDevices;
VideoCaptureDevice videoSource;
 public int selectedDeviceIndex = 0;

启动摄像头示例代码

videoDevices = new FilterInfoCollection(FilterCategory.VideoInputDevice);
            selectedDeviceIndex = 0;
            videoSource = new VideoCaptureDevice(videoDevices[selectedDeviceIndex].MonikerString);//连接摄像头。
            videoSource.VideoResolution = videoSource.VideoCapabilities[selectedDeviceIndex];
            videoSourcePlayer1.VideoSource = videoSource;
            // set NewFrame event handler
            videoSourcePlayer1.Start();

抓拍示代码

if (videoSource == null)
                return;
            Bitmap bitmap = videoSourcePlayer1.GetCurrentVideoFrame();
            string fileName = string.Format("{0}.jpg", DateTime.Now.ToString("yyyyMMddHHmmssfff"));
            this.filePath = string.Format("c:\temp\{0}", fileName);
            bitmap.Save(this.filePath, ImageFormat.Jpeg);
            this.labelControl1.Text = string.Format("存储目录：{0}", this.filePath);
            bitmap.Dispose();
            videoDevices.Clear();

窗体关闭事件

if (this.videoSource != null)
            {
                if (this.videoSource.IsRunning)
                {
                    this.videoSource.Stop();
                }
            }

示例效果