本文通过OpenCV模块调用摄像头，利用百度开放的人体关键点检测API，实现了实时对人体的关键点检测。

一、百度API获取

使用百度的API，首先要在百度AI的官网上注册帐号，然后在人体关键点识别功能下创建一个应用，即可得到
APP_ID、API_KEY、SECRET_KEY，这样就可以调用它的API了。调用方式可以参考其API文档https://ai.baidu.com/ai-doc/BODY/0k3cpyxme
并且需要安装百度的API接口模块：
pip install baidu-aip

二、人体关键点的获取

调用百度API代码如下：

class BaiduAIP(object):
    def __init__(self):
        self.client = AipBodyAnalysis(cfg.APP_ID, cfg.API_KEY, cfg.SECRET_KEY)
    
    def bodyAnalysis(self,img_jpg):
        etval, buffer = cv2.imencode('.jpg', img_jpg)#将jpg格式图片转换成数据流
        result = self.client.bodyAnalysis(buffer) #内部把buffer转换为base64了
        return result

三、人体关键点的绘制

绘制关键点和连线和方框的函数代码：

def draw_line(img,dic,text):
    color=(0,255,0)
    thickness=2
    if(text=='warn'):
        color=(0,0,255)
    
    #nose ---> neck
    cv2.line(img, (int(dic['nose']['x']),int(dic['nose']['y'])),(int(dic['neck']['x']),int(dic['neck']['y'])), color, thickness)
    #neck --> left_shoulder
    cv2.line(img, (int(dic['neck']['x']),int(dic['neck']['y'])),(int(dic['left_shoulder']['x']),int(dic['left_shoulder']['y'])), color, thickness)
    #neck --> right_shoulder
    cv2.line(img, (int(dic['neck']['x']),int(dic['neck']['y'])),(int(dic['right_shoulder']['x']),int(dic['right_shoulder']['y'])), color, thickness)
    #left_shoulder --> left_elbow
    cv2.line(img, (int(dic['left_shoulder']['x']),int(dic['left_shoulder']['y'])),(int(dic['left_elbow']['x']),int(dic['left_elbow']['y'])), color, thickness)
    #left_elbow --> left_wrist
    cv2.line(img, (int(dic['left_elbow']['x']),int(dic['left_elbow']['y'])),(int(dic['left_wrist']['x']),int(dic['left_wrist']['y'])), color, thickness)
    #right_shoulder --> right_elbow
    cv2.line(img, (int(dic['right_shoulder']['x']),int(dic['right_shoulder']['y'])),(int(dic['right_elbow']['x']),int(dic['right_elbow']['y'])), color, thickness)
    #right_elbow --> right_wrist
    cv2.line(img, (int(dic['right_elbow']['x']),int(dic['right_elbow']['y'])),(int(dic['right_wrist']['x']),int(dic['right_wrist']['y'])), color, thickness)
    #neck --> left_hip
    cv2.line(img, (int(dic['neck']['x']),int(dic['neck']['y'])),(int(dic['left_hip']['x']),int(dic['left_hip']['y'])), color, thickness)
    #neck --> right_hip
    cv2.line(img, (int(dic['neck']['x']),int(dic['neck']['y'])),(int(dic['right_hip']['x']),int(dic['right_hip']['y'])), color, thickness)
    #left_hip --> left_knee
    cv2.line(img, (int(dic['left_hip']['x']),int(dic['left_hip']['y'])),(int(dic['left_knee']['x']),int(dic['left_knee']['y'])), color, thickness)
    #right_hip --> right_knee
    cv2.line(img, (int(dic['right_hip']['x']),int(dic['right_hip']['y'])),(int(dic['right_knee']['x']),int(dic['right_knee']['y'])), color, thickness)
    #left_knee --> left_ankle
    cv2.line(img, (int(dic['left_knee']['x']),int(dic['left_knee']['y'])),(int(dic['left_ankle']['x']),int(dic['left_ankle']['y'])), color, thickness)
    #right_knee --> right_ankle
    cv2.line(img, (int(dic['right_knee']['x']),int(dic['right_knee']['y'])),(int(dic['right_ankle']['x']),int(dic['right_ankle']['y'])), color, thickness)
 
def draw_point(img,dic,text):
    color=(0,255,0)
    thickness=2
    if(text=='warn'):
        color=(0,0,255)
    for i in dic:
        cv2.circle(img,(int(dic[i]['x']),int(dic[i]['y'])),5,color,thickness)
 
def draw_box(img,dic,text):
    color=(255,0,0)
    if(text=='warn'):
        color=(0,0,255)
    
    left_top=(int(dic['left']),int(dic['top']))
    left_bottom=(int(dic['left']),int(dic['top']+dic['height']))
    right_bottom=(int(dic['left']+dic['width']),int(dic['top']+dic['height']))
    right_top=(int(dic['left']+dic['width']),int(dic['top']))
    cv2.line(img, left_top,left_bottom, color, 2)
    cv2.line(img, left_top,right_top, color, 2)
    cv2.line(img, right_bottom,left_bottom,color, 2)
    cv2.line(img, right_bottom,right_top,color, 2)
    
    cv2.putText(img, text, (int(dic['left']),int(dic['top'])+20), cv2.FONT_HERSHEY_COMPLEX, 1,color, 1)

四、OpenCV打开摄像头获取人物

打开摄像头获取人物，实现测试需求：

if __name__ == '__main__':
    cap = cv2.VideoCapture(0)
    # cv2.VideoCapture(0)代表调取摄像头资源，其中0代表电脑摄像头，1代表外接摄像头(usb摄像头)
    cap.set(3, 900)
    cap.set(4, 900)
    # cap.set（）设置摄像头参数：3:宽   4:高
    while (1):
        # get a frame
        ret, frame = cap.read()
        # show a frame
        baiduapi = BaiduAIP()
        d = baiduapi.bodyAnalysis(frame)
        persion = d["person_info"]
        for p in persion:
            draw_line(frame,p['body_parts'], 'ok')
            draw_point(frame,p['body_parts'], 'ok')
            draw_box(frame,p['location'], 'beauty')
        cv2.imshow("capture", frame)
        if cv2.waitKey(1) & 0xFF == ord('q'):
            break
    cap.release()
    cv2.destroyAllWindows()

五、结果展示

结果：

                                 不调用摄像头检测图片测试结果

六、总程序

from aip import AipBodyAnalysis
import cv2
import time
class BaiduAIP(object):
    def __init__(self):
        self.client = AipBodyAnalysis(cfg.APP_ID, cfg.API_KEY, cfg.SECRET_KEY)

    def bodyAnalysis(self, img_jpg):
        etval, buffer = cv2.imencode('ww.jpg', img_jpg)
        result = self.client.bodyAnalysis(buffer)  # 内部把buffer转换为base64了
        return result


def draw_line(img, dic, text):
    color = (0, 255, 0)
    thickness = 2
    if (text == 'warn'):
        color = (0, 0, 255)

    # nose ---> neck
    cv2.line(img, (int(dic['nose']['x']), int(dic['nose']['y'])), (int(dic['neck']['x']), int(dic['neck']['y'])), color,
             thickness)
    # neck --> left_shoulder
    cv2.line(img, (int(dic['neck']['x']), int(dic['neck']['y'])),
             (int(dic['left_shoulder']['x']), int(dic['left_shoulder']['y'])), color, thickness)
    # neck --> right_shoulder
    cv2.line(img, (int(dic['neck']['x']), int(dic['neck']['y'])),
             (int(dic['right_shoulder']['x']), int(dic['right_shoulder']['y'])), color, thickness)
    # left_shoulder --> left_elbow
    cv2.line(img, (int(dic['left_shoulder']['x']), int(dic['left_shoulder']['y'])),
             (int(dic['left_elbow']['x']), int(dic['left_elbow']['y'])), color, thickness)
    # left_elbow --> left_wrist
    cv2.line(img, (int(dic['left_elbow']['x']), int(dic['left_elbow']['y'])),
             (int(dic['left_wrist']['x']), int(dic['left_wrist']['y'])), color, thickness)
    # right_shoulder --> right_elbow
    cv2.line(img, (int(dic['right_shoulder']['x']), int(dic['right_shoulder']['y'])),
             (int(dic['right_elbow']['x']), int(dic['right_elbow']['y'])), color, thickness)
    # right_elbow --> right_wrist
    cv2.line(img, (int(dic['right_elbow']['x']), int(dic['right_elbow']['y'])),
             (int(dic['right_wrist']['x']), int(dic['right_wrist']['y'])), color, thickness)
    # neck --> left_hip
    cv2.line(img, (int(dic['neck']['x']), int(dic['neck']['y'])),
             (int(dic['left_hip']['x']), int(dic['left_hip']['y'])), color, thickness)
    # neck --> right_hip
    cv2.line(img, (int(dic['neck']['x']), int(dic['neck']['y'])),
             (int(dic['right_hip']['x']), int(dic['right_hip']['y'])), color, thickness)
    # left_hip --> left_knee
    cv2.line(img, (int(dic['left_hip']['x']), int(dic['left_hip']['y'])),
             (int(dic['left_knee']['x']), int(dic['left_knee']['y'])), color, thickness)
    # right_hip --> right_knee
    cv2.line(img, (int(dic['right_hip']['x']), int(dic['right_hip']['y'])),
             (int(dic['right_knee']['x']), int(dic['right_knee']['y'])), color, thickness)
    # left_knee --> left_ankle
    cv2.line(img, (int(dic['left_knee']['x']), int(dic['left_knee']['y'])),
             (int(dic['left_ankle']['x']), int(dic['left_ankle']['y'])), color, thickness)
    # right_knee --> right_ankle
    cv2.line(img, (int(dic['right_knee']['x']), int(dic['right_knee']['y'])),
             (int(dic['right_ankle']['x']), int(dic['right_ankle']['y'])), color, thickness)


def draw_point(img, dic, text):
    color = (0, 255, 0)
    thickness = 2
    if (text == 'warn'):
        color = (0, 0, 255)
    for i in dic:
        cv2.circle(img, (int(dic[i]['x']), int(dic[i]['y'])), 5, color, thickness)


def draw_box(img, dic, text):
    color = (255, 0, 0)
    if (text == 'warn'):
        color = (0, 0, 255)

    left_top = (int(dic['left']), int(dic['top']))
    left_bottom = (int(dic['left']), int(dic['top'] + dic['height']))
    right_bottom = (int(dic['left'] + dic['width']), int(dic['top'] + dic['height']))
    right_top = (int(dic['left'] + dic['width']), int(dic['top']))
    cv2.line(img, left_top, left_bottom, color, 2)
    cv2.line(img, left_top, right_top, color, 2)
    cv2.line(img, right_bottom, left_bottom, color, 2)
    cv2.line(img, right_bottom, right_top, color, 2)

    cv2.putText(img, text, (int(dic['left']), int(dic['top']) + 20), cv2.FONT_HERSHEY_COMPLEX, 1, color, 1)


if __name__ == '__main__':
    cap = cv2.VideoCapture(0)
    # cv2.VideoCapture(0)代表调取摄像头资源，其中0代表电脑摄像头，1代表外接摄像头(usb摄像头)
    cap.set(3, 900)
    cap.set(4, 900)
    # cap.set（）设置摄像头参数：3:宽   4:高
    while (1):
        # get a frame
        ret, frame = cap.read()
        # show a frame
        baiduapi = BaiduAIP()
        d = baiduapi.bodyAnalysis(frame)
        persion = d["person_info"]
        for p in persion:
            draw_line(frame,p['body_parts'], 'ok')
            draw_point(frame,p['body_parts'], 'ok')
            draw_box(frame,p['location'], 'beauty')
        cv2.imshow("capture", frame)
        if cv2.waitKey(1) & 0xFF == ord('q'):
            break
    cap.release()
    cv2.destroyAllWindows()

通过调用摄像头来实现对人体关键点的检测，对电脑和网络的配置要求有点高。如果设备配置低代码运行起来可能有点卡。

七、 借鉴的博客

https://blog.csdn.net/qq_37394634/article/details/105494672