murtazahassan / learn-opencv-in-3-hours

LEARN OPENCV IN 3 HOURS USING PYTHON - INCLUDING EXAMPLE PROJECTS

What will you learn ?

Virtual Painter	Document Scanner	Number Plate Detector
Contours Detection	Color Detection	Face Detection

Prerequisites

Index	Topic	Image	Video	Description
1	Introduction to Images		Watch Now	Basic concept of Images. The RGB Channels and Gray Scale Images.
2	Installations		Watch Now	Installation process of Pyhton, OpenCV and the Pycharm IDE

Chapters

Chapter	Topic	Image	Video	Description
1	How to Read Image Video-Webcam		Watch Now	Learn how to read images videos and webcam.
2	5 Must Know OpenCV Basic Functions		Watch Now	5 Must know opencv functions for beginners. Gray Scale, Blur, Edge Detection, Dialation and Erosion.
3	How to Crop and Resize Images		Watch Now	How to crop and resize and iamge. Resize could be used to scale up or scale down an image where cropping can be used to get a part of the image.
4	How to Draw Shapes and Text		Watch Now	Learn to create blank images along with how to draw Lines, rectangles, circles and custom text.
5	Warp Prespective/BirdView		Watch Now	Learn how to creat a warp prespective of a selected area of an image using fixed points.
6	Joining Multiple Images to Display		Watch Now	Join multiple images together as one image for easy visualization of the workflow. Learn how to do it for smaller noumber of images and how it could be scaled up to have several images in the same image.
7	Color Detection		Watch Now	How to detect any color in an image using the HSV space with the help of opencv Trackbars.
8	Contour/Shape Detection		Watch Now	How to detect shapes of objects by finding their contours. Contours are basically outline that bound the shape or form of an object. So we will be detecting multiple shapes and how many corners points each shape has along with its area .
9	Face Detection		Watch Now	How to detect faces in realtime using Viola Jones method.
___	___________________	______________________________	__________	____________________________

Projects

Project	Topic	Image	Video	Description
1	Virtual Paint		Watch Now	Detecting Color and using colored marker to draw virtually.
2	Documnet Scanner		Watch Now	In this project we are going to create a simple document scanner using opencv. We will learn how to run this in real time
3	Number Plate Detector		Watch Now	In this project we will detect number plates on cars in realtime and save them with a click of a button.

Notes

Index	Comment
1.	Recommended IDE: PyCharm Community edition
2.	Python: 3.7.6

learn-opencv-in-3-hours's Issues

where we can find video12.mp4 ?

How to add or ceate Resource folder

Assalamu alaykum,
Could you please anyone help me to figure out how to create Resource folder for OpenCv.

ColorPicker.py Question

From project 1 you use the Colorpicker.py to get the right values you need. when running the Code I get a problem with it at:

[ WARN:0] global C:\Users\appveyor\AppData\Local\Temp\1\pip-req-build-2b5g8ysb\opencv\modules\videoio\src\cap_msmf.cpp (435) `anonymous-namespace'::SourceReaderCB::~SourceReaderCB terminating async callback
Traceback (most recent call last):
imgHsv = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
cv2.error: OpenCV(4.4.0)

Im using python 3.7.6 and I have cv2 imported

lambo.png vs lambo.PNG in chapter 3 and chapter 7

The image lambo.png is used in chapter 7, and also in the video for chapter 3.

In the Resources directory the file is labeled lambo.PNG so the above exercises throws an error.

Changing the Resources filename to lambo.png will take care of these errors.

Note: chapter 3 video code uses lambo.png and the GitHub code uses shapes.png. This really is not a problem if lambo.PNG is changed to lambo.png

haarcascades error: (-215:Assertion failed) !empty() in function 'cv::CascadeClassifier::detectMultiScale'

Continue getting this error for drone face tracking course, I think it is due to the file. Any ideas?

My Code:

import cv2
import numpy as np

def findFace(img):
faceCascade = cv2.CascadeClassifier('Resources/haarcascade_frontalface_default.xml')
imgGray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
faces = faceCascade.detectMultiScale(imgGray,1.1,8)

myFaceListC = []
myFaceListArea = []

for (x,y,w,h) in faces:
    cv2.rectangle(img,(x,y),(x + w, y + h),(0,0,255),2)

cap = cv2.VideoCapture(0)

while True:
_, img = cap.read()
findFace(img)
cv2.imshow("Output",img)
cv2.waitKey(1)

Error:

File "C:/Users/zachd/PycharmProjects/droneproject2/venv/Face Tracking.py", line 20, in
findFace(img)
File "C:/Users/zachd/PycharmProjects/droneproject2/venv/Face Tracking.py", line 7, in findFace
faces = faceCascade.detectMultiScale(imgGray,1.1,8)
cv2.error: OpenCV(4.5.1) C:\Users\appveyor\AppData\Local\Temp\1\pip-req-build-oduouqig\opencv\modules\objdetect\src\cascadedetect.cpp:1689: error: (-215:Assertion failed) !empty() in function 'cv::CascadeClassifier::detectMultiScale'

[ WARN:1] global C:\Users\appveyor\AppData\Local\Temp\1\pip-req-build-oduouqig\opencv\modules\videoio\src\cap_msmf.cpp (434) `anonymous-namespace'::SourceReaderCB::~SourceReaderCB terminating async callback

No such file or directory

Hello,

I'm starting to learning python and I'm having difficulties to read the lena's image. When I try to run the program appers the error "no such file or directory". I would like to know how I can fix that.

Att

Project2

What's the function of the project2? Why my computer always display the windows "WorkFlow" but "ImageWarped"

Project 1

IN OPENCV 3 the cv2.findContours function return 3 values.
namely im2, contours, hierarchy.

The code from project 1 throws an error about the unpacking of value or value assign error.

Error about VideoCapture in Virtual Pen

When I set cv2.VideoCapture(1)
img alway get none when cap.read() return.

getting an issue in project1.py file

Traceback (most recent call last):
File "C:/Users/mayur/PycharmProjects/OpenCV projects/read.py", line 20, in
findColor ( img, mycolors )
File "C:/Users/mayur/PycharmProjects/OpenCV projects/read.py", line 16, in findColor
cv2.imshow(img,mask)
cv2.error: OpenCV(4.5.2) 👎 error: (-5:Bad argument) in function 'imshow'

Overload resolution failed:

• Can't convert object of type 'numpy.ndarray' to 'str' for 'winname'
• Can't convert object of type 'numpy.ndarray' to 'str' for 'winname'
• Can't convert object of type 'numpy.ndarray' to 'str' for 'winname'