Category Archives: OpenCV

In this video lesson we show how you can track two different colored objects at the same time in OpenCV. It is the homework solution to the homework we assigned in the last lesson. It will also serve as the starting code for future lessons

import numpy as np
import cv2
print(cv2.__version__)
hueLow=90
hueHigh=100

hueLow2=90
hueHigh2=100

satLow=20
satHigh=200
valLow=20
valHigh=200
def onTrack1(val):
    global hueLow
    hueLow=val
    print('Low Hue: ',val)
def onTrack2(val):
    global hueHigh
    hueHigh=val
    print('High Hue: ',val)
def onTrack3(val):
    global satLow
    satLow=val
    print('Low Sat: ',val)
def onTrack4(val):
    global satHigh
    satHigh=val
    print('High Sat: ',val)
def onTrack5(val):
    global valLow
    valLow=val
    print('Low Val: ',val)
def onTrack6(val):
    global valHigh
    valHigh=val
    print('High Val: ',val)


def onTrack7(val):
    global hueLow2
    hueLow2=val
    print('Low Hue2: ',val)
def onTrack8(val):
    global hueHigh2
    hueHigh2=val
    print('High Hue2: ',val)


width=960
height=540
cam=cv2.VideoCapture(0)
cam.set(cv2.CAP_PROP_FOURCC, cv2.VideoWriter_fourcc(*'MJPG')) 
cam.set(cv2.CAP_PROP_FRAME_WIDTH, width)
cam.set(cv2.CAP_PROP_FRAME_HEIGHT, height)
cv2.namedWindow('myTracker')
cv2.moveWindow('myTracker',width,0)
cv2.resizeWindow('myTracker',400,500)
cv2.createTrackbar('Hue Low','myTracker',15,180,onTrack1)
cv2.createTrackbar('Hue High','myTracker',30,180,onTrack2)

cv2.createTrackbar('Hue Low2','myTracker',50,180,onTrack7)
cv2.createTrackbar('Hue High2','myTracker',60,180,onTrack8)

cv2.createTrackbar('Sat Low','myTracker',10,255,onTrack3)
cv2.createTrackbar('Sat High','myTracker',255,255,onTrack4)
cv2.createTrackbar('Val Low','myTracker',10,255,onTrack5)
cv2.createTrackbar('Val High','myTracker',255,255,onTrack6)


while True:
    ignore,  frame = cam.read()
    frameHSV=cv2.cvtColor(frame,cv2.COLOR_BGR2HSV)

    lowerBound=np.array([hueLow,satLow,valLow])
    upperBound=np.array([hueHigh,satHigh,valHigh])

    lowerBound2=np.array([hueLow2,satLow,valLow])
    upperBound2=np.array([hueHigh2,satHigh,valHigh])

    myMask=cv2.inRange(frameHSV,lowerBound,upperBound)
    myMask2=cv2.inRange(frameHSV,lowerBound2,upperBound2)

    myMask=myMask | myMask2
    #myMask=cv2.add(myMask,myMask2)
    #myMask=np.logical_or(myMask,myMask2)

    #myMask=cv2.bitwise_not(myMask)
    myMaskSmall=cv2.resize(myMask,(int(width/2),int(height/2)))
    mySelection=cv2.bitwise_and(frame,frame, mask=myMask)
    mySelection=cv2.resize(mySelection,(int(width/2),int(height/2)))
    cv2.imshow('My Selection', mySelection)
    cv2.moveWindow('My Selection',int(width/2),height)

    cv2.imshow('My Mask', myMaskSmall)
    cv2.moveWindow('My Mask',0,height)
    cv2.imshow('my WEBcam',frame)
    cv2.moveWindow('my WEBcam',0,0)
    if cv2.waitKey(1) & 0xff ==ord('q'):
        break
cam.release()

100

101

import numpy as np

import cv2

print(cv2.__version__)

hueLow=90

hueHigh=100

hueLow2=90

hueHigh2=100

satLow=20

satHigh=200

valLow=20

valHigh=200

def onTrack1(val):

global hueLow

hueLow=val

print('Low Hue: ',val)

def onTrack2(val):

global hueHigh

hueHigh=val

print('High Hue: ',val)

def onTrack3(val):

global satLow

satLow=val

print('Low Sat: ',val)

def onTrack4(val):

global satHigh

satHigh=val

print('High Sat: ',val)

def onTrack5(val):

global valLow

valLow=val

print('Low Val: ',val)

def onTrack6(val):

global valHigh

valHigh=val

print('High Val: ',val)

def onTrack7(val):

global hueLow2

hueLow2=val

print('Low Hue2: ',val)

def onTrack8(val):

global hueHigh2

hueHigh2=val

print('High Hue2: ',val)

width=960

height=540

cam=cv2.VideoCapture(0)

cam.set(cv2.CAP_PROP_FOURCC, cv2.VideoWriter_fourcc(*'MJPG'))

cam.set(cv2.CAP_PROP_FRAME_WIDTH, width)

cam.set(cv2.CAP_PROP_FRAME_HEIGHT, height)

cv2.namedWindow('myTracker')

cv2.moveWindow('myTracker',width,0)

cv2.resizeWindow('myTracker',400,500)

cv2.createTrackbar('Hue Low','myTracker',15,180,onTrack1)

cv2.createTrackbar('Hue High','myTracker',30,180,onTrack2)

cv2.createTrackbar('Hue Low2','myTracker',50,180,onTrack7)

cv2.createTrackbar('Hue High2','myTracker',60,180,onTrack8)

cv2.createTrackbar('Sat Low','myTracker',10,255,onTrack3)

cv2.createTrackbar('Sat High','myTracker',255,255,onTrack4)

cv2.createTrackbar('Val Low','myTracker',10,255,onTrack5)

cv2.createTrackbar('Val High','myTracker',255,255,onTrack6)

while True:

ignore, frame = cam.read()

frameHSV=cv2.cvtColor(frame,cv2.COLOR_BGR2HSV)

lowerBound=np.array([hueLow,satLow,valLow])

upperBound=np.array([hueHigh,satHigh,valHigh])

lowerBound2=np.array([hueLow2,satLow,valLow])

upperBound2=np.array([hueHigh2,satHigh,valHigh])

myMask=cv2.inRange(frameHSV,lowerBound,upperBound)

myMask2=cv2.inRange(frameHSV,lowerBound2,upperBound2)

myMask=myMask | myMask2

#myMask=cv2.add(myMask,myMask2)

#myMask=np.logical_or(myMask,myMask2)

#myMask=cv2.bitwise_not(myMask)

myMaskSmall=cv2.resize(myMask,(int(width/2),int(height/2)))

mySelection=cv2.bitwise_and(frame,frame, mask=myMask)

mySelection=cv2.resize(mySelection,(int(width/2),int(height/2)))

cv2.imshow('My Selection', mySelection)

cv2.moveWindow('My Selection',int(width/2),height)

cv2.imshow('My Mask', myMaskSmall)

cv2.moveWindow('My Mask',0,height)

cv2.imshow('my WEBcam',frame)

cv2.moveWindow('my WEBcam',0,0)

if cv2.waitKey(1) & 0xff ==ord('q'):

break

cam.release()

OpenCV, Python, Tutorial

Putting Text, Rectangles and Circles on Images in OpenCV for Windows

August 24, 2021 admin

In the video lesson above we show how to add text, rectangles and circles to video frames using OpenCV. Below we include the code with we developed in this lesson. Enjoy!

import cv2
print(cv2.__version__)
width=640
height=360
myRadius=30
myColor=(0,0,0)
myThick=2
fontH=2
fontT=2
myText='Paul is Boss'
myFont=cv2.FONT_HERSHEY_DUPLEX
upperLeft=(250,140)
lowerRight=(390,220)
lineW=4
cam=cv2.VideoCapture(1,cv2.CAP_DSHOW)
cam.set(cv2.CAP_PROP_FRAME_WIDTH, width)
cam.set(cv2.CAP_PROP_FRAME_HEIGHT,height)
cam.set(cv2.CAP_PROP_FPS, 30)
cam.set(cv2.CAP_PROP_FOURCC,cv2.VideoWriter_fourcc(*'MJPG'))
while True:
    ignore,  frame = cam.read()
    frame[140:220,250:390]=(255,0,0)
    cv2.rectangle(frame,upperLeft,lowerRight,(0,255,0),lineW)
    cv2.circle(frame,(int(width/2),int(height/2)),myRadius,myColor,myThick)
    cv2.putText(frame,myText,(120,60),myFont,fontH,(0,0,255),fontT)
    cv2.imshow('my WEBcam', frame)
    cv2.moveWindow('my WEBcam',0,0)
    if cv2.waitKey(1) & 0xff ==ord('q'):
        break
cam.release()

import cv2

print(cv2.__version__)

width=640

height=360

myRadius=30

myColor=(0,0,0)

myThick=2

fontH=2

fontT=2

myText='Paul is Boss'

myFont=cv2.FONT_HERSHEY_DUPLEX

upperLeft=(250,140)

lowerRight=(390,220)

lineW=4

cam=cv2.VideoCapture(1,cv2.CAP_DSHOW)

cam.set(cv2.CAP_PROP_FRAME_WIDTH, width)

cam.set(cv2.CAP_PROP_FRAME_HEIGHT,height)

cam.set(cv2.CAP_PROP_FPS, 30)

cam.set(cv2.CAP_PROP_FOURCC,cv2.VideoWriter_fourcc(*'MJPG'))

while True:

ignore, frame = cam.read()

frame[140:220,250:390]=(255,0,0)

cv2.rectangle(frame,upperLeft,lowerRight,(0,255,0),lineW)

cv2.circle(frame,(int(width/2),int(height/2)),myRadius,myColor,myThick)

cv2.putText(frame,myText,(120,60),myFont,fontH,(0,0,255),fontT)

cv2.imshow('my WEBcam', frame)

cv2.moveWindow('my WEBcam',0,0)

if cv2.waitKey(1) & 0xff ==ord('q'):

break

cam.release()

OpenCV, Python

Controlling a WEBcam in OpenCV on Windows

August 5, 2021 admin

In this lesson we show how to move a frame in OpenCV, how to convert a color image to grayscale, and then how to display multiple video windows. For your convenience, I include the code below that we develop in this video.

import cv2
print(cv2.__version__)
cam=cv2.VideoCapture(1)
while True:
    ignore,  frame = cam.read()
    gray=cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
    cv2.imshow('my WEBcam', frame)
    cv2.moveWindow('my WEBcam',0,0)
    cv2.imshow('my grayFrame', gray)
    cv2.moveWindow('my grayFrame',640,0)

    cv2.imshow('my WEBcam2', frame)
    cv2.moveWindow('my WEBcam2',640,480)
    cv2.imshow('my grayFrame2', gray)
    cv2.moveWindow('my grayFrame2',0,480)
    

    if cv2.waitKey(1) & 0xff ==ord('q'):
        break
cam.release()

import cv2

print(cv2.__version__)

cam=cv2.VideoCapture(1)

while True:

ignore, frame = cam.read()

gray=cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)

cv2.imshow('my WEBcam', frame)

cv2.moveWindow('my WEBcam',0,0)

cv2.imshow('my grayFrame', gray)

cv2.moveWindow('my grayFrame',640,0)

cv2.imshow('my WEBcam2', frame)

cv2.moveWindow('my WEBcam2',640,480)

cv2.imshow('my grayFrame2', gray)

cv2.moveWindow('my grayFrame2',0,480)

if cv2.waitKey(1) & 0xff ==ord('q'):

break

cam.release()

Technology Tutorials

Category Archives: OpenCV

Tracking Two Colors in OpenCV

Putting Text, Rectangles and Circles on Images in OpenCV for Windows

Controlling a WEBcam in OpenCV on Windows

Making The World a Better Place One High Tech Project at a Time. Enjoy!