local variable referenced before assignment，求解

[shuc]

import sensor, image, time,math,pyb

from pid import PID
from pyb import Servo
from pyb import UART,LED
import json
import ustruct

pan_servo=Servo(1) #定义两个舵机
tilt_servo=Servo(2)

pan_servo.calibration(500,2500,500)
tilt_servo.calibration(500,2500,500)

red_threshold_01 = ((14, 88, 24, 116, -18, 106));
bule_threshold_01 = ((16, 65, -20, 35, -64, -21));
yello_threshold_01 = ((53, 71, -14, 0, -7, 22));


pan_pid = PID(p=0.07, i=0, imax=90) #脱机运行或者禁用图像传输，使用这个PID
tilt_pid = PID(p=0.05, i=0, imax=90) #脱机运行或者禁用图像传输，使用这个PID
#pan_pid = PID(p=0.1, i=0, imax=90)#在线调试使用这个PID
#tilt_pid = PID(p=0.1, i=0, imax=90)#在线调试使用这个PID

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_gain(False) # 关闭自动增益
sensor.set_auto_whitebal(False) # turn this off.关闭白平衡
#sensor.set_vflip(True)#垂直方向翻转
clock = time.clock() # Tracks FPS.

uart = UART(3,115200)
uart.init(115200, bits=8, parity=None, stop=1)

def find_max(blobs):
    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

def sending_data(flag):
    global uart;
    data = ustruct.pack("<bbhb",
                   0x2C,
                   0x12,
                   int(flag),
                   0x5B)
    uart.write(data);

while(True):

        flag = None
        clock.tick()
        img = sensor.snapshot()
        blobs = img.find_blobs([red_threshold_01], pixels_threshold=100, area_threshold=100, merge=True, margin=10);      #红色物块
        blobs1 = img.find_blobs([bule_threshold_01], pixels_threshold=100, area_threshold=100, merge=True, margin=10); #绿色物块
        blobs2 = img.find_blobs([yello_threshold_01], pixels_threshold=100, area_threshold=100, merge=True, margin=10);   #黄色物块

        if blobs:
            max_blob = find_max(blobs)#判断最大的色块为哪一个
            #如果找到了目标颜色
            print("red")
            flag = 1
            for b in blobs:
            #迭代找到的目标颜色区域
                # Draw a rect around the blob.
                img.draw_rectangle(max_blob.rect())#img.draw_rectangle(b[0:4]) # rect
                #用矩形标记出目标颜色区域
                img.draw_cross(max_blob.cx(), max_blob.cy())#img.draw_cross(b[5], b[6]) # cx, cy
                #在目标颜色区域的中心画十字形标记
                data = bytearray([0x2C,0x12,flag,0x5B])
                uart.write(data)

            pan_error = max_blob.cx()-img.width()/2
            tilt_error = max_blob.cy()-img.height()/2

            print("pan_error: ", pan_error)

           # img.draw_rectangle(max_blob.rect()) # rect，框选起来
           # img.draw_cross(max_blob.cx(), max_blob.cy()) # cx, cy，框选起来

            pan_output=pan_pid.get_pid(pan_error,1)/2
            tilt_output=tilt_pid.get_pid(tilt_error,1)
            print("pan_output",pan_output)
            pan_servo.angle(pan_servo.angle()+pan_output)#控制舵机转动的角度
            tilt_servo.angle(tilt_servo.angle()-tilt_output)
        elif blobs1:
            max_blob = find_max(blobs)#判断最大的色块为哪一个
            #如果找到了目标颜色
            print("bule")
            flag = 2
            for b in blobs1:
            #迭代找到的目标颜色区域
                # Draw a rect around the blob.
                img.draw_rectangle(max_blob.rect())#img.draw_rectangle(b[0:4]) # rect
                #用矩形标记出目标颜色区域
                img.draw_cross(max_blob.cx(), max_blob.cy())#img.draw_cross(b[5], b[6]) # cx, cy
                #在目标颜色区域的中心画十字形标记
                data = bytearray([0x2C,0x12,flag,0x5B])
                uart.write(data)

            pan_error = max_blob.cx()-img.width()/2
            tilt_error = max_blob.cy()-img.height()/2

            print("pan_error: ", pan_error)

           # img.draw_rectangle(max_blob.rect()) # rect，框选起来
           # img.draw_cross(max_blob.cx(), max_blob.cy()) # cx, cy，框选起来

            pan_output=pan_pid.get_pid(pan_error,1)/2
            tilt_output=tilt_pid.get_pid(tilt_error,1)
            print("pan_output",pan_output)
            pan_servo.angle(pan_servo.angle()+pan_output)#控制舵机转动的角度
            tilt_servo.angle(tilt_servo.angle()-tilt_output)
        elif blobs2:
            max_blob = find_max(blobs)#判断最大的色块为哪一个
            #如果找到了目标颜色
            print("yello")
            flag = 1
            for b in blobs2:
            #迭代找到的目标颜色区域
                # Draw a rect around the blob.
                img.draw_rectangle(max_blob.rect())#img.draw_rectangle(b[0:4]) # rect
                #用矩形标记出目标颜色区域
                img.draw_cross(max_blob.cx(), max_blob.cy())#img.draw_cross(b[5], b[6]) # cx, cy
                #在目标颜色区域的中心画十字形标记
                data = bytearray([0x2C,0x12,flag,0x5B])
                uart.write(data)

            pan_error = max_blob.cx()-img.width()/2
            tilt_error = max_blob.cy()-img.height()/2

            print("pan_error: ", pan_error)

           # img.draw_rectangle(max_blob.rect()) # rect，框选起来
           # img.draw_cross(max_blob.cx(), max_blob.cy()) # cx, cy，框选起来

            pan_output=pan_pid.get_pid(pan_error,1)/2
            tilt_output=tilt_pid.get_pid(tilt_error,1)
            print("pan_output",pan_output)
            pan_servo.angle(pan_servo.angle()+pan_output)#控制舵机转动的角度
            tilt_servo.angle(tilt_servo.angle()-tilt_output)

[kidswong999]

92行应该是blobs1而不是blobs.

120行应该是blobs2而不是blobs.