根据追踪小球的小车的例子做了一个出来，但是发现小车并没有像视频里面那样和小球保持一段距离，识别到了就往前顶，

[nvfd]

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
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.

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.

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 = (76, 96, -110, -30, 8, 66)
size_threshold = 2000
x_pid = PID(p=3, i=1, imax=100)
h_pid = PID(p=0.22, i=0.1, imax=50)

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:
    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, cy
    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:
    car.run(10,-10)

[kidswong999]

size_threshold 改小一些。

如果目标比这个值小，就会往前走。