参考地址：
身份验证：http://ai.baidu.com/ai-doc/FACE/7k37c1ucj
在线活体检测：http://ai.baidu.com/ai-doc/FACE/Zk37c1urr
demo：
<?php
namespace app\common\logic;
use think\Cache;

class Baidu extends Base
{


    private $secret = '';//秘钥
    private $appkey = '';
    private $appid = '';
    private $go_url = '';//访问地址

    /**
     * 刷新token
     * @return \think\response\Json
     */
    protected function refreshToken()
    {
        $param = [
            'grant_type' => 'client_credentials',
            'client_id' => $this->appkey,
            'client_secret' => $this->secret,
        ];

        $url = $this->go_url . '/oauth/2.0/token?' . http_build_query($param);
        $result = httpRequest($url, 1);
        return $result;
    }

    /**
     * 获取token
     * @return bool|mixed
     */
    protected function getToken()
    {
        $token = Cache::get('baidu_token');//读取缓存token 之前获取的
        if ($token) {
            return $token;
        } else {
            $res = $this->refreshToken();
            if (isset($res['access_token'])) {
                Cache::set('baidu_token', $res['access_token'], 864000);//新获取的token 再次保存
                return $res['access_token'];
            }
            return false;
        }
    }
    
    /**
     * 百度 实名认证
     * @param $image 身份证图片
     * @param $id_card 身份证号
     * @param $name 姓名
     * @return bool|mixed
     */
    public function realname($image, $id_card, $name)
    {
        $token = $this->getToken();
        $param = [
            'image' => $image,
            'image_type' => 'URL',
            'id_card_number' => $id_card,
            'name' => $name,
        ];
        $url = $this->go_url . '/rest/2.0/face/v3/person/verify?access_token=' . $token;

        $result = $this->request_post($url, json_encode($param));
        return $result;
    }

    /**
     * 百度 活体检测
     * @param $image 检测的照片
     * @return bool|mixed
     */
    public function imgcheck($image)
    {
        $token = $this->getToken();
        $param = [[
            'image' => $image,
            'image_type' => 'URL',
        ]];
        $url = $this->go_url . '/rest/2.0/face/v3/faceverify?access_token=' . $token;
        $result = $this->request_post($url, json_encode($param));
        return $result;
    }


    function jcHttpDataPost($url, $data, $json_transfer = 1)
    {
        if ($json_transfer == 1) {
            $data = json_encode($data, JSON_UNESCAPED_UNICODE);
        } else if ($json_transfer == 2) {
            $data = urldecode(json_encode($data, JSON_UNESCAPED_UNICODE));
        }


        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
        curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (compatible; MSIE 5.01; Windows NT 5.0)');
        curl_setopt($ch, CURLOPT_AUTOREFERER, 1);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        $status = curl_exec($ch);
        curl_close($ch);
        $res = json_decode($status, true);
        return $res;
    }

    function request_post($url = '', $param = '')
    {
        if (empty($url) || empty($param)) {
            return false;
        }

        $postUrl = $url;
        $curlPost = $param;
        // 初始化curl
        $curl = curl_init();
        curl_setopt($curl, CURLOPT_URL, $postUrl);
        curl_setopt($curl, CURLOPT_HEADER, 0);
        // 要求结果为字符串且输出到屏幕上
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
        // post提交方式
        curl_setopt($curl, CURLOPT_POST, 1);
        curl_setopt($curl, CURLOPT_POSTFIELDS, $curlPost);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
        // 运行curl
        $data = curl_exec($curl);
        curl_close($curl);
        $res = json_decode($data, true);
        return $res;
    }
}