第一次使用百度API C#程序（测试用）
最近实现
详细查看完整代码Github:https://github.com/122537067/PeopleDetect
首先阅读文档
http://ai.baidu.com/docs#/Face-Detect-V3/top
第一步：注册百度账号获取Access TOKEN
添加应用
得到Secret Key 和API Key
API Key 对应文档中的 clientId
SecretKey 对应文档中的 clientSecret
百度云文档C#源码如下
using System;
using System.Collections.Generic;
using System.Net.Http;
namespace com.baidu.ai
{
public static class AccessToken
{
// 调用getAccessToken()获取的 access_token建议根据expires_in 时间 设置缓存
// 返回token示例
public static String TOKEN = "24.adda70c11b9786206253ddb70affdc46.2592000.1493524354.282335-1234567";
// 百度云中开通对应服务应用的 API Key 建议开通应用的时候多选服务
private static String clientId = "百度云应用的AK";
// 百度云中开通对应服务应用的 Secret Key
private static String clientSecret = "百度云应用的SK";
public static String getAccessToken() {
String authHost = "https://aip.baidubce.com/oauth/2.0/token";
HttpClient client = new HttpClient();
List<KeyValuePair<String, String>> paraList = new List<KeyValuePair<string, string>>();
paraList.Add(new KeyValuePair<string, string>("grant_type", "client_credentials"));
paraList.Add(new KeyValuePair<string, string>("client_id", clientId));
paraList.Add(new KeyValuePair<string, string>("client_secret", clientSecret));
HttpResponseMessage response = client.PostAsync(authHost, new FormUrlEncodedContent(paraList)).Result;
String result = response.Content.ReadAsStringAsync().Result;
Console.WriteLine(result);
return result;
}
}
}到这步可以测试一下Access Token是否已经获取成功（获取失败代码参见文档http://ai.baidu.com/docs#/Auth/9d0f74c9）
第二步：调用接口，获取JSON数据
// 人脸检测与属性分析
public static string detect(String PictureBase64)
{
string token = AccessToken.getAccessToken();
string host = "https://aip.baidubce.com/rest/2.0/face/v3/detect?access_token=" + token;
Encoding encoding = Encoding.Default;
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(host);
request.Method = "post";
request.KeepAlive = true;
String str = "{\"image\":\"" + PictureBase64 + "\",\"image_type\":\"BASE64\",\"face_field\":\"age,type\"}";
byte[] buffer = encoding.GetBytes(str);
request.ContentLength = buffer.Length;
request.GetRequestStream().Write(buffer, 0, buffer.Length);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.Default);
string result = reader.ReadToEnd();
Console.WriteLine("人脸检测与属性分析:");
Console.WriteLine(result);
return result;
}str是接口处理的数据，我image_type使用的是BASE64，face_field只返回了age和type的属性，其他属性参见文档自己添加
文档的str是这样写，根据自己需求可以替换添加
String str = "{\"image\":\"027d8308a2ec665acb1bdf63e513bcb9\",\"image_type\":\"FACE_TOKEN\",\"face_field\":\"faceshape,facetype\"}";例如我想直接饮用网上的图片路径（URL），则这样写
String str = "{\"image\":\"https://timgsa.baidu.com/timg?image&quality=80&size=b9999_10000&sec=1533237885029&di=71c13d1cb749956107720a0c94f40876&imgtype=0&src=http%3A%2F%2Fimgsrc.baidu.com%2Fimgad%2Fpic%2Fitem%2F9a504fc2d56285358e6bf5d59aef76c6a6ef63be.jpg\",\"image_type\":\"URL\",\"face_field\":\"faceshape,facetype\"}";
使用BASE64类型的话要将图片转换成BASE64形式，然后调用接口。
第二步：JSON数据的解析
调用接口返回的是JSON数据，需要对JSON数据进行转换。
下载开源的类库Newtonsoft.Json(下载地址 http://json.codeplex.com/ )。
（或者直接在VS里面下载）
定义类定义JSON数据，可以使用工具http://json2csharp.chahuo.com/
使用方法：将要处理的json字符串复制到文本框即可以得到C#类，如图所示：
解析JSON数据的代码如下:
private void button_change_Click(object sender, EventArgs e)
{
//解析JSON数据
RootObject people = JsonConvert.DeserializeObject<RootObject>(textBox_token.Text);
//获取值
textBox_token.Text = "转换结果：";
textBox_token.Text += people.error_msg + "\r\n" + "\r\n";
textBox_token.Text += "这是一张人脸的概率：";
textBox_token.Text += people.result.face_list[0].face_probability + "\r\n" + "\r\n";
textBox_token.Text += "年龄：";
textBox_token.Text += people.result.face_list[0].age + "\r\n" + "\r\n";
textBox_token.Text += "颜值：";
textBox_token.Text += people.result.face_list[0].beauty + "\r\n" + "\r\n";
textBox_token.Text += "表情：";
textBox_token.Text += people.result.face_list[0].expression.probability + "概率是";
string expression_type = people.result.face_list[0].expression.type;
if(expression_type == "none") { expression_type = "冷漠脸"; }
else if(expression_type == "smile") { expression_type = "微笑"; }
else if (expression_type == "laugh") { expression_type = "大笑"; }
else { expression_type = "都不知道你什么表情"; }
textBox_token.Text += expression_type + "\r\n" + "\r\n";
//square: 正方形 triangle:三角形 oval: 椭圆 heart: 心形 round: 圆形
textBox_token.Text += "脸型：";
textBox_token.Text += people.result.face_list[0].face_shape.probability + "概率是";
string faceShape = people.result.face_list[0].face_shape.type;
if (faceShape == "square") { faceShape = "正方形"; }
else if (faceShape == "triangle") { faceShape = "三角形"; }
else if (faceShape == "oval") { faceShape = "椭圆"; }
else if (faceShape == "heart") { faceShape = "心形"; }
else if (faceShape == "round") { faceShape = "圆形"; }
else { faceShape = "都不知道你什么头"; }
textBox_token.Text += faceShape + "\r\n" + "\r\n";
//male:男性 female:女性
textBox_token.Text += "性别：";
textBox_token.Text += people.result.face_list[0].gender.probability + "概率是";
string sex = people.result.face_list[0].gender.type;
if (sex == "male") { sex = "男性"; }
else if (sex == "female") { sex = "女性"; }
else { sex = "都不知道你什么性别"; }
textBox_token.Text += sex + "\r\n" + "\r\n";
//none:无眼镜，common:普通眼镜，sun:墨镜
textBox_token.Text += "眼镜类型：";
textBox_token.Text += people.result.face_list[0].glasses.probability + "概率是";
string glasse = people.result.face_list[0].glasses.type;
if (glasse == "none") { glasse = "无眼镜"; }
else if (glasse == "common") { glasse = "普通眼镜"; }
else if (glasse == "sun") { glasse = "墨镜"; }
else { faceShape = "眼呢？"; }
textBox_token.Text += glasse + "\r\n" + "\r\n";
//yellow: 黄种人 white: 白种人 black:黑种人 arabs: 阿拉伯人
textBox_token.Text += "种族：";
textBox_token.Text += people.result.face_list[0].race.probability + "概率是";
string race = people.result.face_list[0].race.type;
if (race == "yellow") { race = "黄种人"; }
else if (race == "white") { race = "白种人"; }
else if (race == "black") { race = "黑种人"; }
else if (race == "arabs") { race = "阿拉伯人"; }
else { race = "人呢？"; }
textBox_token.Text += race + "\r\n" + "\r\n";
}
}详细查看完整代码Github:https://github.com/122537067/PeopleDetect