OpenMV识别颜色源码

# 导入文件
import sensor, image, time, pyb
from pyb import UART,Pin,Timer
import json

# 初始化摄像头
sensor.reset()
sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.QVGA)
sensor.skip_frames(time=2000)  # 等待摄像头稳定
sensor.set_auto_gain(False)    # 关闭自动增益。在颜色识别中，需要关闭自动增益
sensor.set_auto_whitebal(False)
clock = time.clock()

tim = Timer(4, freq=1000) # Frequency in Hz
led_dac = tim.channel(1, Timer.PWM, pin=Pin("P7"), pulse_width_percent=50)
led_dac.pulse_width_percent(100)
# 定义颜色阈值
red_threshold = (33, 100, 17, 127, -25, 52)    # 红色阈值
green_threshold = (54, 20, -47, -18, -15, 41)  # 绿色阈值
yellow_threshold = (40, 100, -56, 81, 25, 127) # 黄色阈值

# 初始化串口
uart = pyb.UART(3, 115200)  # 使用UART3，波特率115200
# 定义帧头和帧尾
FRAME_HEADER = 0xAA
FRAME_TAIL = 0x55

# 上一次发送的颜色
last_detected_color = None

def find_max_blob(blobs):
    max_blob = None

    max_size = 0
    for blob in blobs:
        if blob.pixels() > max_size:
            max_size = blob.pixels()
            max_blob = blob
    return max_blob

while(True):
    clock.tick()                       # 更新FPS帧率时钟
    img = sensor.snapshot()

    # 查找色块
    red_blobs = img.find_blobs([red_threshold], pixels_threshold=100, area_threshold=100)
    green_blobs = img.find_blobs([green_threshold], pixels_threshold=100, area_threshold=100)
    yellow_blobs = img.find_blobs([yellow_threshold], pixels_threshold=100, area_threshold=100)

    red_blob = find_max_blob(red_blobs)
    green_blob = find_max_blob(green_blobs)
    yellow_blob = find_max_blob(yellow_blobs)

    if red_blob:
        detected_color = "R"
    elif green_blob:
        detected_color = "G"
    elif yellow_blob:
        detected_color = "Y"
    else:
        detected_color = "N" # 没有识别到颜色

    # 绘制矩形框和文字标注
    if detected_color == "R":
        img.draw_rectangle(red_blob.rect(), color=(255, 0, 0))  # 用红色矩形框圈出红色物块
        img.draw_cross(red_blob.cx(), red_blob.cy(),color=(255, 0, 0), size=10)
        img.draw_string(red_blob.x(), red_blob.y() - 10, "Red", color=(255, 0, 0))  # 显示文字
    elif detected_color == "G":
        img.draw_rectangle(green_blob.rect(), color=(0, 255, 0))  # 用绿色矩形框圈出绿色物块
        img.draw_cross(green_blob.cx(), green_blob.cy(),color=(0, 255, 0), size=10)
        img.draw_string(green_blob.x(), green_blob.y() - 10, "Green", color=(0, 255, 0))  # 显示文字
    elif detected_color == "Y":
        img.draw_rectangle(yellow_blob.rect(), color=(255, 255, 0))  # 用黄色矩形框圈出黄色物块
        img.draw_cross(yellow_blob.cx(), yellow_blob.cy(),color=(255, 255, 0), size=10)
        img.draw_string(yellow_blob.x(), yellow_blob.y() - 10, "Yellow", color=(255, 255, 0))  # 显示文字

    # 发送颜色指令到STM32，如果识别到颜色且与上一次不同，发送带帧头和帧尾的颜色指令到STM32
    if detected_color is not None and detected_color != last_detected_color:
        uart.writechar(FRAME_HEADER)  # 发送帧头
        uart.write(detected_color)    # 发送颜色指令
        uart.writechar(FRAME_TAIL)    # 发送帧尾
    last_detected_color = detected_color  # 更新上一次发送的颜色
    time.sleep_ms(10)  # 延时100ms
    print("FPS %f" % clock.fps())  # 打印帧率