Charles Cooper

Charles Cooper

1547824839

Image Matching result in images where it shouldn't be one (Python opencv tutorial)

I'm working with the following python opencv example:

import cv2
import numpy as np
from matplotlib import pyplot as plt

img = cv2.imread(‘messi5.jpg’,0)
img2 = img.copy()
template = cv2.imread(‘template.jpg’,0)
w, h = template.shape[::-1]

All the 6 methods for comparison in a list

methods = [‘cv2.TM_CCOEFF’, ‘cv2.TM_CCOEFF_NORMED’, ‘cv2.TM_CCORR’,
‘cv2.TM_CCORR_NORMED’, ‘cv2.TM_SQDIFF’, ‘cv2.TM_SQDIFF_NORMED’]

for meth in methods:
img = img2.copy()
method = eval(meth)

# Apply template Matching
res = cv2.matchTemplate(img,template,method)
min_val, max_val, min_loc, max_loc = cv2.minMaxLoc(res)

# If the method is TM_SQDIFF or TM_SQDIFF_NORMED, take minimum
if method in [cv2.TM_SQDIFF, cv2.TM_SQDIFF_NORMED]:
    top_left = min_loc
else:
    top_left = max_loc
bottom_right = (top_left[0] + w, top_left[1] + h)

cv2.rectangle(img,top_left, bottom_right, 255, 2)

plt.subplot(121),plt.imshow(res,cmap = 'gray')
plt.title('Matching Result'), plt.xticks([]), plt.yticks([])
plt.subplot(122),plt.imshow(img,cmap = 'gray')
plt.title('Detected Point'), plt.xticks([]), plt.yticks([])
plt.suptitle(meth)

plt.show()

The matching works pretty well on a set of chosen images, which clearly contained the template. My problem is that even in images which clearly doesn’t contain the template a rectangle was drawn. How can I fit the source code, so it can handle image which doesn’t match at all.

Thanks in advance

#python #opencv

What is GEEK

Buddha Community

Zak Dyer

1547866116

In the document:

It returns a grayscale image, where each pixel denotes how much does the neighbourhood of that pixel match with template
So set a threshold for the res, if there is no similarity in the image, it does nothing.

res = cv2.matchTemplate(img,template,method)
if res<0.8:
    return
...

Just like in the Template Matching with Multiple Objects part

John David

1548144449

Your code always shows the best match, regardless of how good the match is.

You could check the value of max_val (or min_val when SQDIFF is used) and only show the match when this value exceeds a certain threshold.

Ray  Patel

Ray Patel

1619518440

top 30 Python Tips and Tricks for Beginners

Welcome to my Blog , In this article, you are going to learn the top 10 python tips and tricks.

1) swap two numbers.

2) Reversing a string in Python.

3) Create a single string from all the elements in list.

4) Chaining Of Comparison Operators.

5) Print The File Path Of Imported Modules.

6) Return Multiple Values From Functions.

7) Find The Most Frequent Value In A List.

8) Check The Memory Usage Of An Object.

#python #python hacks tricks #python learning tips #python programming tricks #python tips #python tips and tricks #python tips and tricks advanced #python tips and tricks for beginners #python tips tricks and techniques #python tutorial #tips and tricks in python #tips to learn python #top 30 python tips and tricks for beginners

Python and OpenCV: Apply Filters to Images

I am pretty sure you have tried out various filters available on the social platforms and your camera as well.

Today in this tutorial, we will be applying few of the filters to images. Exciting right?

Let’s begin!

Table of Contents

1. Importing Modules

2. Loading the initial image

#python programming examples #python and opencv: apply filters to images #apply filters to images #python and opencv #opencv #filters to images

Ray  Patel

Ray Patel

1619510796

Lambda, Map, Filter functions in python

Welcome to my Blog, In this article, we will learn python lambda function, Map function, and filter function.

Lambda function in python: Lambda is a one line anonymous function and lambda takes any number of arguments but can only have one expression and python lambda syntax is

Syntax: x = lambda arguments : expression

Now i will show you some python lambda function examples:

#python #anonymous function python #filter function in python #lambda #lambda python 3 #map python #python filter #python filter lambda #python lambda #python lambda examples #python map

Python Imread(): Different Ways to Load an Image using The OpenCV.imread() Method

In this tutorial, we will learn how to use imread() method of OpenCV-Python in detail and different ways to load an image using imread() method.

Table of Contents

What is Python imread()?

Importing OpenCV to use Python imread()

Syntax of the Python imread() method

Image formats supported by Python imread() method

#python modules #opencv-python #python imread() #opencv.imread() #python imread(): different ways to load an image using the opencv.imread() method #load an image

Art  Lind

Art Lind

1602968400

Python Tricks Every Developer Should Know

Python is awesome, it’s one of the easiest languages with simple and intuitive syntax but wait, have you ever thought that there might ways to write your python code simpler?

In this tutorial, you’re going to learn a variety of Python tricks that you can use to write your Python code in a more readable and efficient way like a pro.

Let’s get started

Swapping value in Python

Instead of creating a temporary variable to hold the value of the one while swapping, you can do this instead

>>> FirstName = "kalebu"
>>> LastName = "Jordan"
>>> FirstName, LastName = LastName, FirstName 
>>> print(FirstName, LastName)
('Jordan', 'kalebu')

#python #python-programming #python3 #python-tutorials #learn-python #python-tips #python-skills #python-development