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.

Updated version available at GitHub

First install Linux+OpenCV3+Python3.5, Firmata and also Flask:

apt-get install python3-flask

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, Event
from PyMata.pymata import PyMata

# Motor pins on Arduino
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 signal_handler(sig, frame):
    board.reset()

# Here we initialize the motor pins on Arduino
board = PyMata(bluetooth=False)
signal.signal(signal.SIGINT, signal_handler)
board.set_pin_mode(MOTOR_1_PWM, board.PWM,    board.DIGITAL)
board.set_pin_mode(MOTOR_1_A,   board.OUTPUT, board.DIGITAL)
board.set_pin_mode(MOTOR_1_B,   board.OUTPUT, board.DIGITAL)
board.set_pin_mode(MOTOR_2_PWM, board.PWM,    board.DIGITAL)
board.set_pin_mode(MOTOR_2_A,   board.OUTPUT, board.DIGITAL)
board.set_pin_mode(MOTOR_2_B,   board.OUTPUT, board.DIGITAL)
board.set_pin_mode(MOTOR_3_PWM, board.PWM,    board.DIGITAL)
board.set_pin_mode(MOTOR_3_A,   board.OUTPUT, board.DIGITAL)
board.set_pin_mode(MOTOR_3_B,   board.OUTPUT, board.DIGITAL)

class MotorThread(Thread):
    def __init__(self):
        Thread.__init__(self)
        self.daemon = True
        self.lock = Event()
        self.set(0, 0, 0)
        
    def set(self, m1, m2, m3):
        self.m1, self.m2, self.m3 = m1, m2, m3
        self.lock.set()

    def run(self):
        while True:
            board.digital_write(MOTOR_1_B, 0) # Reset all direction pins to avoid damaging H-bridges
            board.digital_write(MOTOR_1_A, 0)
            board.digital_write(MOTOR_2_B, 0)
            board.digital_write(MOTOR_2_A, 0)
            board.digital_write(MOTOR_3_B, 0)
            board.digital_write(MOTOR_3_A, 0)
            board.analog_write(MOTOR_1_PWM, int(abs(self.m1) + 25) if self.m1 else 0) # Set duty cycle
            board.analog_write(MOTOR_2_PWM, int(abs(self.m2) + 25) if self.m2 else 0)
            board.analog_write(MOTOR_3_PWM, int(abs(self.m3) + 25) if self.m3 else 0)
            board.digital_write(MOTOR_1_A, self.m1 < 0) # Set directions
            board.digital_write(MOTOR_1_B, self.m1 > 0)
            board.digital_write(MOTOR_2_A, self.m2 < 0)
            board.digital_write(MOTOR_2_B, self.m2 > 0)
            board.digital_write(MOTOR_3_A, self.m3 < 0)
            board.digital_write(MOTOR_3_B, self.m3 > 0)
            self.lock.wait()
            self.lock.clear()

class FrameGrabber(Thread):
    # Set HSV color ranges, this basically means color red regardless of saturation or brightness
    BALL_LOWER = ( 0, 140, 140)
    BALL_UPPER = (10, 255, 255)
 
    def __init__(self, width=640, height=480):
        Thread.__init__(self)
        self.daemon = True
        self.video = cv2.VideoCapture(0)

        # PS3 eye config:
        self.video.set(3, width)             # Set capture width to 640px
        self.video.set(4, height)            # Set capture height to 480px
        self.video.set(cv2.CAP_PROP_FPS, 60) # Set framerate to 60 fps
       
        self.cx, self.cy = width / 2, height
        self.timestamp = time()
        self.frames = 0
        self.fps = 0
        self.last_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() # Grab another frame from the camera
            blurred = cv2.blur(frame, (4,4))
            hsv = cv2.cvtColor(blurred, cv2.COLOR_BGR2HSV) # Convert red, green and blue to hue, saturation and brightness
            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]

            distance = None
            
            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 > 10:
                    cv2.circle(frame, center, int(radius), (0, 0, 255), 5)
                    distance = round((1/radius)*100*11.35, 2)
                    cv2.putText(frame, str(radius), (int(x),int(y)), cv2.FONT_HERSHEY_SIMPLEX, 0.7,(255,255,255),1)
                    
            if distance:
                dx = (x - self.cx) / 2.0
                dy = (self.cy - y) / 3.0
                adx = abs(dx)

                if adx > 100:
                    if dx > 0:
                        cv2.putText(frame,"Going right %d" % adx, (10,40), cv2.FONT_HERSHEY_SIMPLEX, 0.3,(255,255,255),1)
                        motors.set(adx, adx, adx)
                    else:
                        cv2.putText(frame,"Going left %d" % adx, (10,40), cv2.FONT_HERSHEY_SIMPLEX, 0.3,(255,255,255),1)
                        motors.set(-adx, -adx, -adx)
                else:
                    cv2.putText(frame,"Going forward %d" % dy, (10,40), cv2.FONT_HERSHEY_SIMPLEX, 0.3,(255,255,255),1)
                    motors.set(100 + dy, -100 -dy, dx)
            else:
                cv2.putText(frame,"Stopping", (10,40), cv2.FONT_HERSHEY_SIMPLEX, 0.3,(255,255,255),1)
                motors.set(0, 0, 0)

            cv2.putText(frame,"%.01f fps" % self.fps, (10,20), cv2.FONT_HERSHEY_SIMPLEX, 0.3,(255,255,255),1)
            self.last_frame = np.hstack([frame, cutout])

motors = MotorThread()
motors.start()

grabber = FrameGrabber() 
grabber.start()

app = Flask(__name__)
 
@app.route('/')
def index():
    def generator():
        while True:
            if grabber.last_frame != None:
                ret, jpeg = cv2.imencode('.jpg', grabber.last_frame, (cv2.IMWRITE_JPEG_QUALITY, 80))
                yield b'--frame\r\nContent-Type: image/jpeg\r\n\r\n' + jpeg.tostring() + b'\r\n\r\n'
            sleep(0.05)
    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)