# Measure the distance
#
# This example shows off how to measure the distance through the size in imgage
# This example in particular looks for yellow pingpong ball.

import sensor, image, time
import json
# For color tracking to work really well you should ideally be in a very, very,
# very, controlled enviroment where the lighting is constant...
yellow_threshold   = (27, 61, 36, 127, -128, 127)
# You may need to tweak the above settings for tracking green things...
# Select an area in the Framebuffer to copy the color settings.
from pyb import UART
sensor.reset() # Initialize the camera sensor.
sensor.set_pixformat(sensor.RGB565) # use RGB565.
sensor.set_framesize(sensor.QQVGA) # use QQVGA for speed.
sensor.skip_frames(10) # Let new settings take affect.
sensor.set_auto_whitebal(False) # turn this off.
clock = time.clock() # Tracks FPS.
uart = UART(3, 9600)
K=640#the value should be measured

while(True):
    clock.tick() # Track elapsed milliseconds between snapshots().
    img = sensor.snapshot() # Take a picture and return the image.

    blobs = img.find_blobs([yellow_threshold])
    if len(blobs) == 1:
        # Draw a rect around the blob.
        b = blobs[0]
        img.draw_rectangle(b[0:4]) # rect
        img.draw_cross(b[5], b[6]) # cx, cy
        if 0<b[5]<160/3 and 0<b[6]<40:
            uart.write('0x01')
            #print(b[5],b[6])
        if b[5]<320/3 and b[6]<40:
            uart.write('2')
            #print(b[5],b[6])
        if 320/3<b[5]<160 and 0<b[6]<40:
            uart.write('3')
            #print(b[5],b[6])
        if 0<b[5]<160/3 and 40<b[6]<80:
            uart.write('4')
            #print(b[5],b[6])
        if 160/3<b[5]<320/3 and 40<b[6]<80:
            uart.write('5')
            #print(b[5],b[6])
        if 320/3<b[5]<160 and 40<b[6]<80:
            uart.write('6')
            #print(b[5],b[6])
        if 0<b[5]<160/3 and 80<b[6]<120:
            uart.write('7')
            #print(b[5],b[6])
        if 160/3<b[5]<320/3 and 80<b[6]<120:
            uart.write('8')
            #print(b[5],b[6])
        if 320/3<b[5]<160 and 80<b[6]<120:
            uart.write('9')
            #print(b[5],b[6])
    #print(clock.fps()) # Note: Your OpenMV Cam runs about half as fast while
    # connected to your computer. The FPS should increase once disconnected.

怎么给arduino传16进制的数字1，2，3，4，5，，，，

import sensor, image, time

sensor.reset()
sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.QQVGA)
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()

K=660#the value should be measured
yellow_threshold   = (9, 62, 9, 65, -80, -7)
def find_max(blobs):
    max_size=0
    for blob in blobs:
        if blob.pixels() > max_size:
            max_blob=blob
            max_size = blob.pixels()
    return max_blob
while(True):
    clock.tick()
    img = sensor.snapshot()
    sensor.set_hmirror(False) #水平方向翻转
    sensor.set_vflip(False) #垂直方向翻转
    blobs = img.find_blobs([yellow_threshold])


    #if not blobs:
    for r in img.find_rects(threshold = 30000):
        img.draw_rectangle(r.rect(), color = (255, 0, 0))
        area = (r.x(),r.y(),r.w(),r.h())
        for p in r.corners():
            img.draw_circle(p[0], p[1], 5, color = (0, 255, 0))
  #  for c in img.find_circles(threshold = 3500, x_margin = 10, y_margin = 10, r_margin = 10,
   #     r_min = 2, r_max = 100, r_step = 2):
        print (r)
        #area为识别到的圆的区域，即圆的外接矩形框
        statistics = img.get_statistics(roi=area)#像素颜色统计
        #print(statistics)
        #(94, 100, -128, 127, -128, 127)是红色的阈值，所以当区域内的众数（也就是最多的颜色），范围在这个阈值内，就说明是红色的圆。
        #l_mode()，a_mode()，b_mode()是L通道，A通道，B通道的众数。
        if 56<statistics.l_mode()<79 and 35<statistics.a_mode()<127 and -128<statistics.b_mode()<127:#if the circle is red
            img.draw_rectangle(area, color = (255, 255, 255))
            #将非红色的圆用白色的矩形框出来
    if blobs :#and len(blobs)==1 :就是这里应该怎么改！！！！！！！！！！！！！！
                # Draw a rect around the blob.
        max_blob=find_max(blobs)
        img.draw_rectangle(max_blob.rect())
        img.draw_cross(max_blob.cx(), max_blob.cy())
        output_str="[%d,%d]\n" % (max_blob.cx(),max_blob.cy()) #方式1
                #output_str=json.dumps([max_blob.cx(),max_blob.cy()]) #方式2
        print('you send:',output_str)
        b = blobs[0]
        img.draw_rectangle(b[0:4]) # rect
        img.draw_cross(b[5], b[6]) # cx, cy
        Lm = (b[2]+b[3])/2
        length = K/Lm
                #print(Lm)
        print(length)

怎么设置找到我要的颜色阈值并且该物体是矩形，就是一个物体需要满足，是矩形和是我设置的颜色阈值这两个条件才会被识别出来，所以if语句应该怎么写

@4oqs

import sensor, image, time

sensor.reset()
sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.QQVGA)
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()

K=500#the value should be measured
yellow_threshold   = (56, 79, 35, 127, -128, 127)
def find_max(blobs):   #识别最大色块
   max_size=0
   for blob in blobs:
      if blob[2]*blob[3] > max_size:
        max_blob=blob
        max_size = blob[2]*blob[3]
   return max_blob
while(True):
    clock.tick()
    img = sensor.snapshot().lens_corr(1.8)
    sensor.set_hmirror(False) #水平方向翻转
    sensor.set_vflip(False) #垂直方向翻转
    for r in img.find_rects(threshold = 20000):
        img.draw_rectangle(r.rect(), color = (255, 0, 0))
        area = (r.x(),r.y(),r.w(),r.h())        
        for p in r.corners(): img.draw_circle(p[0], p[1], 5, color = (0, 255, 0))
  #  for c in img.find_circles(threshold = 3500, x_margin = 10, y_margin = 10, r_margin = 10,
   #     r_min = 2, r_max = 100, r_step = 2):
        print (r)
        #area为识别到的圆的区域，即圆的外接矩形框
        statistics = img.get_statistics(roi=area)#像素颜色统计
       #print(statistics)
        #(94, 100, -128, 127, -128, 127)是红色的阈值，所以当区域内的众数（也就是最多的颜色），范围在这个阈值内，就说明是红色的圆。
        #l_mode()，a_mode()，b_mode()是L通道，A通道，B通道的众数。
        if 56<statistics.l_mode()<79 and 35<statistics.a_mode()<127 and -128<statistics.b_mode()<127:#if the circle is red
            img.draw_rectangle(area, color = (255, 255, 255))
            #将非红色的圆用白色的矩形框出来

    blobs = img.find_blobs([yellow_threshold])
    
    if len(blobs) == 1:
        # Draw a rect around the blob.
        max_blob=find_max(blobs)
        b = blobs[0]
        img.draw_rectangle(b[0:4]) # rect
        img.draw_cross(b[5], b[6]) # cx, cy
        Lm = (b[2]+b[3])/2
        length = K/Lm
        #print(Lm)
        print(length)

你试试看，我这里用的是红色的阈值

@4oqs 你这纯复制粘贴。。。。咋会有用呢，k的值没改，距离是不对的，而且输出的是像素，不是距离
另外这个是识别圆形区域的

能不能识别多种颜色然后同时画框