PyRobovision

This page is simply to show off the MVP using Python, OpenCV, Firmata, Flask. Currently the robot is able to turn towards the golf ball and then approach it.

It supports streaming MJPEG to the browser as well.

Corresponding Python source:

import cv2
import numpy as np
import signal
import sys
from flask import Flask, render_template, Response
from collections import deque
from datetime import datetime
from time import time, sleep
from threading import Thread
from PyMata.pymata import PyMata

class Motors(Thread):
    MOTOR_1_PWM = 2
    MOTOR_1_A   = 3
    MOTOR_1_B   = 4
    MOTOR_2_PWM = 5
    MOTOR_2_A   = 6
    MOTOR_2_B   = 7
    MOTOR_3_PWM = 8
    MOTOR_3_A   = 9
    MOTOR_3_B   = 10
    
    def __init__(self):
        Thread.__init__(self)
        self.daemon = True
        self.board = PyMata()
        def signal_handler(sig, frame):
            self.stop_motors()
            self.board.reset()
            sys.exit(0)
        signal.signal(signal.SIGINT, signal_handler)
        self.board.set_pin_mode(self.MOTOR_1_PWM, self.board.PWM,    self.board.DIGITAL)
        self.board.set_pin_mode(self.MOTOR_1_A,   self.board.OUTPUT, self.board.DIGITAL)
        self.board.set_pin_mode(self.MOTOR_1_B,   self.board.OUTPUT, self.board.DIGITAL)
        self.board.set_pin_mode(self.MOTOR_2_PWM, self.board.PWM,    self.board.DIGITAL)
        self.board.set_pin_mode(self.MOTOR_2_A,   self.board.OUTPUT, self.board.DIGITAL)
        self.board.set_pin_mode(self.MOTOR_2_B,   self.board.OUTPUT, self.board.DIGITAL)
        self.board.set_pin_mode(self.MOTOR_3_PWM, self.board.PWM,    self.board.DIGITAL)
        self.board.set_pin_mode(self.MOTOR_3_A,   self.board.OUTPUT, self.board.DIGITAL)
        self.board.set_pin_mode(self.MOTOR_3_B,   self.board.OUTPUT, self.board.DIGITAL)
        self.dx, self.dy = 0, 0
        
    def stop_motors(self):
        self.board.digital_write(self.MOTOR_1_B, 0)
        self.board.digital_write(self.MOTOR_1_A, 0)
        self.board.digital_write(self.MOTOR_2_B, 0)
        self.board.digital_write(self.MOTOR_2_A, 0)
        self.board.digital_write(self.MOTOR_3_B, 0)
        self.board.digital_write(self.MOTOR_3_A, 0)

    def run(self):
        while True:
            # Reset all direction pins to avoid damaging H-bridges
            self.stop_motors()

            dist = abs(self.dx)
            if dist > 2:
                if self.dx > 0:
                    print("Turning left")
                    self.board.digital_write(self.MOTOR_1_B, 1)
                    self.board.digital_write(self.MOTOR_2_B, 1)
                    self.board.digital_write(self.MOTOR_3_B, 1)
                else:
                    print("Turning right")
                    self.board.digital_write(self.MOTOR_1_A, 1)
                    self.board.digital_write(self.MOTOR_2_A, 1)
                    self.board.digital_write(self.MOTOR_3_A, 1)
                self.board.analog_write(self.MOTOR_1_PWM, int(dist ** 0.7 + 25))
                self.board.analog_write(self.MOTOR_2_PWM, int(dist ** 0.7 + 25))
                self.board.analog_write(self.MOTOR_3_PWM, int(dist ** 0.7 + 25))
            elif self.dy > 30:
                print("Going forward")
                self.board.digital_write(self.MOTOR_1_B, 1)
                self.board.digital_write(self.MOTOR_3_A, 1)
                self.board.analog_write(self.MOTOR_1_PWM, int(self.dy ** 0.5 )+30)
                self.board.analog_write(self.MOTOR_2_PWM, 0)
                self.board.analog_write(self.MOTOR_3_PWM, int(self.dy ** 0.5 )+30)
            sleep(0.03)

class FrameGrabber(Thread):
    BALL_LOWER = ( 5, 140, 140)
    BALL_UPPER = (30, 255, 255)

    def __init__(self, width=320, height=240):
        Thread.__init__(self)
        self.daemon = True
        self.video = cv2.VideoCapture(0)
        self.video.set(3, width)
        self.video.set(4, height)
        self.timestamp = time()
        self.frames = 0
        self.fps = 50
        self.current_frame = None

    def run(self):
        while True:
            self.frames += 1
            timestamp_begin = time()
            if self.frames > 10:
                self.fps = self.frames / (timestamp_begin - self.timestamp)
                self.frames = 0
                self.timestamp = timestamp_begin
            success, frame = self.video.read()
            frame = cv2.flip(frame, 1)
            original = frame
            blurred = cv2.blur(frame, (4,4))
            hsv = cv2.cvtColor(blurred, cv2.COLOR_BGR2HSV)
            mask = cv2.inRange(hsv, self.BALL_LOWER, self.BALL_UPPER)
            mask = cv2.dilate(mask, None, iterations=2)
            cutout = cv2.bitwise_and(frame,frame, mask= mask)
            cnts = cv2.findContours(mask, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)[-2]
            if len(cnts) > 0:
                c = max(cnts, key=cv2.contourArea)
                (x, y), radius = cv2.minEnclosingCircle(c)
                M = cv2.moments(c)
                center = (int(M["m10"] / M["m00"]), int(M["m01"] / M["m00"]))
                if radius > 5:
                    cv2.circle(frame, (int(x), int(y)), int(radius),
                        (0, 255, 255), 2)
                    cv2.circle(frame, center, 5, (0, 0, 255), -1)
                    radius = 1/radius
                    radius = round(radius*100*11.35, 2)
                    cv2.putText(original,str(radius),(int(x),int(y)), cv2.FONT_HERSHEY_SIMPLEX, 0.7,(255,255,255),1,cv2.LINE_AA)
                    cv2.putText(original,str(radius),(int(x+3),int(y)), cv2.FONT_HERSHEY_SIMPLEX, 0.59,(0,0,0),1,cv2.LINE_AA)
                    delta = int((x-160)/5.0)
                    motors.dx, motors.dy = delta, 240-y
            cv2.putText(frame,"%.01f fps" % self.fps, (10,20), cv2.FONT_HERSHEY_SIMPLEX, 0.3,(255,255,255),1,cv2.LINE_AA)
            self.current_frame = np.hstack([original, cutout])

motors = Motors()
grabber = FrameGrabber()
motors.start()
grabber.start()

app = Flask(__name__)

@app.route('/')
def index():
    def generator():
        while True:
            if grabber.current_frame != None:
                ret, jpeg = cv2.imencode('.jpg', grabber.current_frame, (cv2.IMWRITE_JPEG_QUALITY, 20))
                yield b'--frame\r\nContent-Type: image/jpeg\r\n\r\n' + jpeg.tobytes() + b'\r\n\r\n'
            sleep(0.3) # Approx 3fps for web browser
    return Response(generator(), mimetype='multipart/x-mixed-replace; boundary=frame')

if __name__ == '__main__':
    app.run(host='0.0.0.0', debug=True,use_reloader=False,threaded=True)