# Blob Detection Example
#
# This example shows off how to use the find_blobs function to find color
# blobs in the image. This example in particular looks for dark green objects.
import sensor, image, time, pyb
import car
from pid import PID
# You may need to tweak the above settings for tracking green things...
# Select an area in the Framebuffer to copy the color settings.
led = pyb.LED(3)
led.on()
time.sleep_ms(150)
led.off()
time.sleep_ms(100)
led.on()
time.sleep_ms(150)
led.off()
time.sleep_ms(100)
led.on()
time.sleep_ms(150)
led.off()
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(50) # Let new settings take affect.
sensor.set_auto_whitebal(False) # turn this off.
clock = time.clock() # Tracks FPS.
# For color tracking to work really well you should ideally be in a very, very,
# very, controlled enviroment where the lighting is constant...
green_threshold = (22, 85, -66, -28, -29, 65)
#green_threshold = (0, 16, 12, 33, -1, 24)
size_threshold = 2000
x_pid = PID(p=0.5, i=1, imax=0)
h_pid = PID(p=0.03, i=0.1, imax=0)
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
while(True):
clock.tick() # Track elapsed milliseconds between snapshots().
img = sensor.snapshot() # Take a picture and return the image.
blobs = img.find_blobs([green_threshold])
if blobs:
last_time = pyb.millis()
max_blob = find_max(blobs)
x_error = max_blob[5]-img.width()/2
h_error = max_blob[2]*max_blob[3]-size_threshold
print("x error: ", x_error)
'''
for b in blobs:
# Draw a rect around the blob.
img.draw_rectangle(b[0:4]) # rect
img.draw_cross(b[5], b[6]) # cx, cy
'''
img.draw_rectangle(max_blob[0:4]) # rect
img.draw_cross(max_blob[5], max_blob[6]) # cx, cya
x_output=x_pid.get_pid(x_error,1)
h_output=h_pid.get_pid(h_error,1)
print("h_output",h_output)
car.run(-h_output-x_output,-h_output+x_output)
else:
if pyb.elapsed_millis(last_time) % 2000 > 1000:
car.run(10,0)
else
car.run(-10,0)
思路就是不用while 用if，然后每次找到色块后更新时间。