图像处理案例02

1 流程

手指拖拽屏幕上的方块儿步骤

1. OpenCv获取视频流
2. 获取手指关节关键点坐标
3. 判断手指是否在方块上
4. 如果在方块上，方块跟着手指移动

2 代码

import cv2
import numpy as np
import math
import mediapipe as mp## 检测手掌参数设置
mp_drawing = mp.solutions.drawing_utils
mp_drawing_styles = mp.solutions.drawing_styles
mp_hands = mp.solutions.hands
# 获取手的21个关节
hands = mp_hands.Hands(model_complexity=0,min_detection_confidence=0.5,min_tracking_confidence=0.5)
# 获取摄像头的视频流
cap = cv2.VideoCapture(0)# 获取画面宽度,高度
width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
# 方块的相关参数
## box左上角坐标、宽度、颜色
box_x = 100
box_y = 100
box_width = 100
box_high  = 120
box_color = (255, 0, 255)
## 阈值，当食指和中指指尖距离大于阈值时，停止移动box
threth = 80
## 食指指尖与box左上角坐标的距离
d1 = 0
d2 = 0
## 食指指尖是否在方块上
on_box = Falsewhile True:# 1. 读取每一帧ret, frame = cap.read()# 对图像进行处理# 镜像处理，对y轴进行翻转frame = cv2.flip(frame, 1)# mediapipe处理RGB通道的图像frame.flags.writeable = Falseframe = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)## 2.手掌检测RGB图像results = hands.process(frame)frame.flags.writeable = Trueframe = cv2.cvtColor(frame, cv2.COLOR_RGB2BGR)# 判断是否检测到手掌if results.multi_hand_landmarks:# 遍历每一只手掌for hand_landmarks in results.multi_hand_landmarks:# 绘制手掌的21个关键点mp_drawing.draw_landmarks(frame,hand_landmarks,mp_hands.HAND_CONNECTIONS,mp_drawing_styles.get_default_hand_landmarks_style(),mp_drawing_styles.get_default_hand_connections_style())# 保存手掌的21个x,y的坐标x_list = []y_list = []for landmark in hand_landmarks.landmark:  # 会循环21次把手的关节弄好# 添加x坐标x_list.append(landmark.x)  # append表示添加x坐标# 添加y坐标y_list.append(landmark.y)# 获取食指指尖xy坐标index_finger_x = int(x_list[8] * width)index_finger_y = int(y_list[8] * height)# 获取中指指尖，用于退出方块middle_finger_x = int(x_list[12] * width)middle_finger_y = int(y_list[12] * height)# 计算食指指尖和中指指尖的欧式距离finger_len = math.hypot((index_finger_x - middle_finger_x),(index_finger_y - middle_finger_y))if finger_len < threth:# 3. 判断指尖是否在方块上面if (box_x < index_finger_x < box_x + box_width and box_y < index_finger_y < box_y + box_high):if on_box == False:## 如果食指在box内移动，则保持d1、d2不更新，即box与食指的相对位置不变d1 = abs(index_finger_x - box_x)d2 = abs(index_finger_y - box_y)on_box = True## 如果食指在box上，则变换box为水红色box_color = (255, 0, 255)else:on_box = False## 如果食指不在box上，则变换box为蓝颜box_color = (255, 0, 0)if on_box:  # 如果手指在方块上面        box_x = index_finger_x - d1  # 根据算法box_y = index_finger_y - d2# 4. 画出boxcv2.rectangle(frame, (box_x, box_y), (box_x + box_width, box_y + box_high), box_color, -1)frame = cv2.addWeighted(frame.copy(), 0.5, frame, 0.5, 0)  # 做一个半透明# 显示图像cv2.imshow('Box drag', frame)# 退出条件if cv2.waitKey(10) & 0xFF == ord('q'):break
cap.release()
cv2.destroyAllWindows()