（1）人脸1：N检测，返回人脸对应用户信息
（2）活体检测：识别活体还好图片，防止人脸作弊
（3）人脸注册：检测用户是否存在
在正式开始之前，需要一些准备以及预备知识，这里可以参考https://www.cnblogs.com/xiongze520/p/10387355.html以及https://www.cnblogs.com/xiongze520/p/10688545.html，讲的很详细。这里主要将后端的代码逻辑。
（1）人脸注册
在人脸注册前需要检测人脸库是否存在该人脸，已经存在了，则终止注册行为
代码如下：改方法接受前端返回的data64的图片字节串流，调用百度人脸识别接口方法进行判断，这里写了一个_faceEFService的数据库服务类，采用了EF core， var userModel = _faceEFService.GetByGuiIdAsync(userId).Result;返回数据库中userId对应的用户信息，其中userId是在注册人脸的时候，就保存到了百度云控制后台。
public IActionResult CheckIfUserHave(string imgData64FromAjax) { imgData64 = imgData64FromAjax; string ApiKey = "ApiKey "; string SecretKey = "SecretKey "; var client = new Baidu.Aip.Face.Face(ApiKey, SecretKey); client.Timeout = 10000; var imageType = "BASE64"; //BASE64 URL string requestImgData64 = imgData64FromAjax; requestImgData64 = requestImgData64.Substring(imgData64.IndexOf(",") + 1); string groupId = "FaceGroupForNetCore"; //string userId = new Guid().ToString(); var findUserJsonResult = client.Search(requestImgData64, imageType, groupId); //会出现222207（未找到用户）这个错误 if (findUserJsonResult["error_code"].ToString() == "0" && findUserJsonResult["error_msg"].ToString() == "SUCCESS") { var userList = JArray.Parse(findUserJsonResult["result"]["user_list"].ToString()); foreach (var user in userList) { var score = Convert.ToInt32(user["score"].ToString().Substring(0, 2)); if (score > 80) { Guid userId = Guid.Parse(user["user_id"].ToString()); var userModel = _faceEFService.GetByGuiIdAsync(userId).Result; if (userModel != null) { var returnModel = new FaceReconitionModel { UserName = userModel.UserName }; return Json(returnModel.UserName); } } } } if (findUserJsonResult["error_code"].ToString() == "222202") { return Json("无法识别到人脸"); } return View(); }（2）人脸注册：这块没啥了，大家应该都懂，就不介绍了。。。
[HttpPost] public IActionResult FaceRegister( [FromForm] FaceReconitionModel faceReconitionModel) { string ApiKey = "ApiKey "; string SecretKey = "ApiKey "; var client = new Baidu.Aip.Face.Face(ApiKey, SecretKey); client.Timeout = 10000; var imageType = "BASE64"; //BASE64 URL imgData64 = imgData64.Substring(imgData64.IndexOf(",") + 1); string groupId = "FaceGroupForNetCore"; string userId = Guid.NewGuid().ToString("N"); var userInfo = Guid.NewGuid(); var options = new Dictionary<string, object>{ {"user_info", userInfo.ToString()}, {"quality_control", "NORMAL"}, {"liveness_control", "LOW"}, {"action_type", "REPLACE"} }; var addUserFace = client.UserAdd(imgData64, imageType, groupId, userId, options); var model = new FaceMdel { UserName = faceReconitionModel.UserName, Month = faceReconitionModel.Month.ToString(), Sex = faceReconitionModel.Sex, Works = faceReconitionModel.Works, Position = faceReconitionModel.Position, GuidId = Guid.Parse(userId) }; _faceEFService.AddAsync(model); // _faceEFService.SaveChangeAsnc(); return RedirectToAction("index"); }（3）人脸活体检测以及人脸1：N检测
这里只要是人脸活体检测以及1：N检测，根据返回的UserId查找出数据库中对应的用户信息，依然很简单，大家应该看的懂。。
public IActionResult FaceDistinguish(string faceImgData64) { FaceImgData64 = faceImgData64; string ApiKey = "ApiKey "; string SecretKey = "ApiKey "; var client = new Baidu.Aip.Face.Face(ApiKey, SecretKey); client.Timeout = 10000; // var imageType = "BASE64"; //BASE64 URL faceImgData64 = faceImgData64.Substring(faceImgData64.IndexOf(",") + 1); // string groupId = "FaceGroupForNetCore"; var faces = new JArray { new JObject { {"image", faceImgData64}, {"image_type", "BASE64"} } }; var checkLiving = client.Faceverify(faces); //"error_code": 222202, if (checkLiving["error_code"].ToString() == "0" && checkLiving["error_msg"].ToString() == "SUCCESS") { // var Living_result = Newtonsoft.Json.JsonConvert.DeserializeObject(LivingObj["result"].ToString()) as JObject; var livingList = checkLiving["result"]["thresholds"]; double faceLiveness = Convert.ToDouble(checkLiving["result"]["face_liveness"].ToString()); //var frr = Newtonsoft.Json.JsonConvert.SerializeObject(Living_list.ToString()); //var frr_1eObj = Newtonsoft.Json.JsonConvert.DeserializeObject(Living_list.ToString()) as JObject; double frr_1e4 = Convert.ToDouble(livingList["frr_1e-4"].ToString()); if (faceLiveness < frr_1e4) { return Json("不是活体"); } } if (checkLiving["error_code"].ToString() == "222202") { return Json("无法识别到人脸"); } return Json("活体检验通过"); }