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
Tag: Images
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
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
How To Install PIL On Ubuntu
Let's say you want to play around with images in Python. To do that, we need a Python package that can handle all the image manipulation. Python Imaging Library (PIL) is one of most popular libraries that is used to process the image data. Actually, people use Pillow now, which is a modern repackaged version of … Continue reading How To Install PIL On Ubuntu
How To Take A Screenshot On Mac OS X
One of the many good things about Mac OS X is the built in support for taking screenshots. But then again, in this day and age, what operating system doesn't? Well, this is where it differs a little. I am sure most of you know how to capture a screenshot on OS X, but there … Continue reading How To Take A Screenshot On Mac OS X
Reading JPEG Into A Byte Array
Let's say you are working with images for your project. A lot of times, when you have to work across multiple platforms, the encoding doesn't remain the same. In these scenarios, you cannot process images directly by treating them like 2D matrices. One of the most common image formats you will comes across is JPEG. … Continue reading Reading JPEG Into A Byte Array
Perpetual Enigma 