import sensor, image, time
from pid import PID
from pyb import Servo
pan_servo=Servo(1)
tilt_servo=Servo(2)
pan_servo.calibration(500,2500,500)
tilt_servo.calibration(500,2500,500)
red_threshold = (13, 49, 18, 61, 6, 47)
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_contrast(3)
sensor.set_gainceiling(16)
sensor.set_pixformat(sensor.GRAYSCALE) # use RGB565.
sensor.set_framesize(sensor.QQVGA) # use QQVGA for speed.s
sensor.skip_frames(10) # Let new settings take affect.
sensor.set_auto_whitebal(False) # turn this off.
clock = time.clock() # Tracks FPS.
face_cascade = image.HaarCascade("frontalface", stages=25)
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_features(face_cascade, threshold=0.75, scale=1.35)
if blobs:
max_blob = find_max(blobs)
pan_error = max_blob[0]+max_blob[2]/2-img.width()/2
tilt_error =max_blob[1]+max_blob[3]/2
print("pan_error: ", pan_error)
img.draw_rectangle(max_blob) # rect
img.draw_cross(int(max_blob[0]+max_blob[2]/2), int(max_blob[1]+max_blob[3]/2)) # cx, cy
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)
tilt_servo.angle(tilt_servo.angle()-tilt_output)
from pyb import millis
from math import pi, isnan
class PID:
_kp = _ki = _kd = _integrator = _imax = 0
_last_error = _last_derivative = _last_t = 0
_RC = 1/(2 * pi * 20)
def __init__(self, p=0, i=0, d=0, imax=0):
self._kp = float(p)
self._ki = float(i)
self._kd = float(d)
self._imax = abs(imax)
self._last_derivative = float('nan')
def get_pid(self, error, scaler):
tnow = millis()
dt = tnow - self._last_t
output = 0
if self._last_t == 0 or dt > 1000:
dt = 0
self.reset_I()
self._last_t = tnow
delta_time = float(dt) / float(1000)
output += error * self._kp
if abs(self._kd) > 0 and dt > 0:
if isnan(self._last_derivative):
derivative = 0
self._last_derivative = 0
else:
derivative = (error - self._last_error) / delta_time
derivative = self._last_derivative + \
((delta_time / (self._RC + delta_time)) * \
(derivative - self._last_derivative))
self._last_error = error
self._last_derivative = derivative
output += self._kd * derivative
output *= scaler
if abs(self._ki) > 0 and dt > 0:
self._integrator += (error * self._ki) * scaler * delta_time
if self._integrator < -self._imax: self._integrator = -self._imax
elif self._integrator > self._imax: self._integrator = self._imax
output += self._integrator
return output
def reset_I(self):
self._integrator = 0
self._last_derivative = float('nan')