Open MV与STM32通信 寻找色块，循迹

最近在实验室准备电赛，由于电赛要用到摄像头，我便开始学习openmv，学习也有一段时间了想分享一下自己的心得，自己做了一个小车来寻找色块和循迹。

OPENMV端 分享一些我自己之前找到的一些openmv资料：

https://blog.csdn.net/qq_43243338/article/details/89441756 我自己看的这篇博客和官方的资料才搞懂

1.在IDE中先需要引入一些库和写好模块的配置程序

import sensor, image, time,math,pyb from pyb import UART,LED import json import ustruct sensor.reset() sensor.set_pixformat(sensor.RGB565) sensor.set_framesize(sensor.QVGA) sensor.skip_frames(time = 2000) sensor.set_auto_gain(False) # must be turned off for color tracking sensor.set_auto_whitebal(False) # must be turned off for color tracking clock = time.clock() //关于这些配置程序的作用都可在官方文档中查到

2.openmv与stm32通信是通过串口来通信，需要在openmv上配置串口。

uart = UART(3,115200) #定义串口3变量 uart.init(115200, bits=8, parity=None, stop=1) # init with given parameters

3.openmv通过micropython里的find_blobs函数来寻找色块。 官方教程：

https://www.bilibili.com/video/BV1RW411G7oy https://book.openmv.cc/image/blob.html 看懂这些教程就能看懂这个程序

通过find_blobs函数返回的数据可得到色块的坐标等参数

find_blobs函数返回的参数：https://docs.singtown.com/micropython/zh/latest/openmvcam/library/omv.image.html#blob ![在这里插入图片描述](https://img-blog.csdnimg.cn/20201007185127703.png?

```python while(True): clock.tick() img = sensor.snapshot() blobs = img.find_blobs([red_threshold_01]); cx=0;cy=0; if blobs: #如果找到了目标颜色 max_b = find_max(blobs); # Draw a rect around the blob. img.draw_rectangle(max_b[0:4]) # rect #用矩形标记出目标颜色区域 img.draw_cross(max_b[5], max_b[6]) # cx, cy #img.draw_cross(160, 120) # 在中心点画标记 #在目标颜色区域的中心画十字形标记 cx=max_b[5]; cy=max_b[6]; cw=max_b[2]; ch=max_b[3];

4.数据发送程序 这个地方用到了ustruct.pack这个函数，要注意的是对数据的打包格式。

def sending_data(cx,cy,cw,ch): global uart; #frame=[0x2C,18,cx%0xff,int(cx/0xff),cy%0xff,int(cy/0xff),0x5B]; #data = bytearray(frame) data = ustruct.pack("<bbhhhhb", #b和h对应的是数据的格式 0x2C, #帧头1 0x12, #帧头2 int(cx), # up sample by 4 #数据1 int(cy), # up sample by 4 #数据2 int(cw), # up sample by 4 #数据1 int(ch), # up sample by 4 #数据2 0x5B) uart.write(data); #必须要传入一个字节数组

不可直接使用串口发送数据，最好要使用帧头，否则数据会出现错误

完整程序

寻找色块的中点 - By: dengbei - 周三 9月 30 2020 import sensor, image, time,math,pyb from pyb import UART,LED import json import ustruct LED_R = pyb.LED(1) # Red LED = 1, Green LED = 2, Blue LED = 3, IR LEDs = 4. LED_G = pyb.LED(2) LED_B = pyb.LED(3) LED_R.on() LED_G.on() LED_B.on() red_threshold_01 = ((2, 51, 11, 127, -128, 127)); #红色阈值 sensor.reset() sensor.set_pixformat(sensor.RGB565) sensor.set_framesize(sensor.QVGA) sensor.skip_frames(time = 2000) sensor.set_auto_gain(False) # must be turned off for color tracking sensor.set_auto_whitebal(False) # must be turned off for color tracking clock = time.clock() LED_G.off() uart = UART(3,115200) #定义串口3变量 uart.init(115200, bits=8, parity=None, stop=1) # init with given parameters def find_max(blobs): #定义寻找色块面积最大的函数 max_size=0 for blob in blobs: if blob.pixels() > max_size: max_blob=blob max_size = blob.pixels() return max_blob def sending_data(cx,cy,cw,ch): global uart; #frame=[0x2C,18,cx%0xff,int(cx/0xff),cy%0xff,int(cy/0xff),0x5B]; #data = bytearray(frame) data = ustruct.pack("<bbhhhhb", #格式为俩个字符俩个短整型(2字节) 0x2C, #帧头1 0x12, #帧头2 int(cx), # up sample by 4 #数据1 int(cy), # up sample by 4 #数据2 int(cw), # up sample by 4 #数据1 int(ch), # up sample by 4 #数据2 0x5B) uart.write(data); #必须要传入一个字节数组 def recive_data(): global uart if uart.any(): tmp_data = uart.readline(); print(tmp_data) while(True): clock.tick() img = sensor.snapshot() blobs = img.find_blobs([red_threshold_01]); cx=0;cy=0; if blobs: #如果找到了目标颜色 max_b = find_max(blobs); # Draw a rect around the blob. img.draw_rectangle(max_b[0:4]) # rect #用矩形标记出目标颜色区域 img.draw_cross(max_b[5], max_b[6]) # cx, cy #img.draw_cross(160, 120) # 在中心点画标记 #在目标颜色区域的中心画十字形标记 cx=max_b[5]; cy=max_b[6]; cw=max_b[2]; ch=max_b[3]; #img.draw_line((160,120,cx,cy), color=(127)); #img.draw_string(160,120, "(%d, %d)"%(160,120), color=(127)); #img.draw_string(cx, cy, "(%d, %d)"%(cx,cy), color=(127)); #print(cx); #print(cy); sending_data(cx,cy,cw,ch); #发送点位坐标 recive_data(); #print(img.width())

STM32端接收程序 1.使用串口的中断来接收和解析数据

2.完整程序

u8 RxBuffer1[19]; u8 RxCounter1 = 0; u8 RxFlag1 = 0; void USART2_IRQHandler(void) { u8 temp; if( USART_GetITStatus(USART2,USART_IT_RXNE)!=RESET ) { USART_ClearITPendingBit(USART2,USART_IT_RXNE);//清除中断标志 temp = USART_ReceiveData(USART2); Openmv_Receive_Data(temp);//openmv数据处理函数 } } void Openmv_Receive_Data(int16_t data)//接收Openmv传过来的数据 { static u8 state = 0; if(state==0&&data==0x2C) { state=1; RxBuffer1[RxCounter1++]=data; } else if(state==1&&data==18) { state=2; RxBuffer1[RxCounter1++]=data; } else if(state==2) { RxBuffer1[RxCounter1++]=data; if(RxCounter1>19||data == 0x5B) state=3; //the last of char is openmv[19] } else if(state==3) //state == 3 检测是否接受到结束标志 { if(RxBuffer1[RxCounter1-1] == 0x5B) { state = 0; RxFlag1 = 1; USART_ITConfig(USART1,USART_IT_RXNE,DISABLE); } else //wrong thing { state = 0; RxCounter1=0; } } else //wrong thing { state = 0; RxCounter1=0; } } u16 posX,posY,posW,posH,image_area;//寻找物块参数 int16_t theta_err,rho_err; //巡线参数 void USART2_Rx_Task(void) { if(RxFlag1 == 1) { posX = RxBuffer1[3]<<8 | RxBuffer1[2]; posY = RxBuffer1[7]<<8 | RxBuffer1[6]; // posX = RxBuffer1[3]<<8 | RxBuffer1[2]; // posY = RxBuffer1[5]<<8 | RxBuffer1[4]; posW = RxBuffer1[7]<<8 | RxBuffer1[6]; posH = RxBuffer1[9]<<8 | RxBuffer1[8]; image_area = posW * posH; RxFlag1 = 0; RxCounter1 = 0; USART_ITConfig(USART1,USART_IT_RXNE,ENABLE); } }

stm32接收数据后的寻找色块的程序写在另外一篇博客里。