Reading an image from a file is fairly straightforward in OpenCV-Python. But a lot of times, we would like to read an image from a URL and process it in OpenCV. One way to do it is to download the image, save it as a jpeg file, and then read it in OpenCV. But that's … Continue reading How To Read An Image From A URL In OpenCV-Python
Category: Computer Vision
Installing OpenCV 3 With Python On Mac OS X
OpenCV is the world's most popular computer vision library and it's used extensively by researchers and developers around the world. OpenCV has been around for a while now and they add something new and interesting with every new release. One of the main additions of OpenCV 3 is "opencv_contrib" which contains a lot of cutting … Continue reading Installing OpenCV 3 With Python On Mac OS X
Image Classification Using Fisher Vectors
This is a continuation of my previous blog post on image classification and the bag of words (BoW) model. If you already know how BoW works, then you will feel right at home. If you need a refresher, you can read the blog post here. In our previous post, we discussed how BoW works, and … Continue reading Image Classification Using Fisher Vectors
Image Classification Using Bag-Of-Words Model
Image classification is one of the classical problems in computer vision. Basically, the goal is to determine whether or not the given image contains a particular thing like an object or a person. Humans tend to classify images effortlessly, but machines seem to have a hard time doing this. Computer Vision has achieved some success in … Continue reading Image Classification Using Bag-Of-Words Model
What Is A Markov Chain?
If you have studied probability theory, then you must have heard Markov's name. When we study probability and statistics, we tend to deal with independent trials. What this means is that if you conduct an experiment a lot of times, we assume that the outcome of one trial doesn't influence the outcome of the next … Continue reading What Is A Markov Chain?
The Concept Of Homogeneous Coordinates
People in computer vision and graphics deal with homogeneous coordinates on a very regular basis. They are actually a nice extension of standard three dimensional vectors and allow us to simplify various transforms and their computations. When I say "transformations", I am talking about all those special effects on the screen, and the corresponding movements … Continue reading The Concept Of Homogeneous Coordinates
Understanding Camera Calibration
Cameras have been around for a long time now. When cameras were first introduced, they were expensive and you needed a good amount of money to own one. However, people then came up with pinhole cameras in the late 20th century. These cameras were inexpensive and they became a common occurrence in our everyday life. … Continue reading Understanding Camera Calibration
What Is Gamma Correction?
Gamma correction is an integral part of all the digital imaging systems, but a lot of people don't know about it! It is an essential part of all the imaging devices like cameras, camcorders, monitors, video players, etc. It basically defines the relationship between a pixel's numerical value and its actual luminance. Now wait a … Continue reading What Is Gamma Correction?
Recognizing Shapes Using Point Distribution Models
In the field of computer vision, we often come across situations where we need to recognize the shapes of different objects. Not only that, we also need our machines to understand the shapes so that we can identify them even if we encounter them in different forms. Humans are really good at these things. We somehow … Continue reading Recognizing Shapes Using Point Distribution Models
Understanding Gabor Filters
In the field of image processing, filters play an extremely important role. If you don't know what a filter is, you may quickly want to read the wiki article and come back. Otherwise, this post will not make much sense to you. All image processing operations can be viewed as applying a series of filters … Continue reading Understanding Gabor Filters
Perpetual Enigma 