Browse by category

Noise reduction by Averaging

Noise reduction by averaging

What?! Averaging? You mean blurring? No. This method does not use any type of blurring to reduce noise in a particular image. Infact, the result is the opposite blurring: you get sharp images! In the averaging method, it is assumed that you have several images of the same object… each with a different “noise pattern”. [...]

Read more

Noise Models

Noise

Models?! Where?!?!! Technically, it is possible to “represent” random noise as a mathematical function. And that is exactly what a model is. The “distribution” of noise is based on probability. Hence the model is called a Probability Density Function (PDF). Once noise has been quantified, creating filters to get rid of it becomes a lot [...]

Read more

Generating uniform noise

Noise

Uniform Noise Uniform noise means the different “values” of noise are equally probably. Its probability density function looks something like this: If you don’t understand what this graph (probability distribution function) means, you might want to have a look at the article on Noise Models. Generating uniform random numbers Here the plan of action to [...]

Read more

Color spaces

Colourspaces

Introduction Images are stored in memory in various different colour spaces. You might have heard of one, the RGB colour space. That is the one Windows uses a lot. For image processing purposes, one often needs other colour spaces that better suit the purpose of the application. In this article, I’ll go through the RGB [...]

Read more

Thresholding

Thresholding basics in OpenCV

Introduction Thresholding is one of the most basic techniques for what is called Image Segmentation. When you threshold an image, you get segments inside the image… each representing something. For example… complex segmentation algorithms might be able to segment out “house-like” structures in an image. With thresholding, you can segment the image based on colour. [...]

Read more

An introduction to contours

Detection!

Introduction In this tutorial, you’ll get to know how to use contours. You can think of contours as a boundary. Consider the following thresholded image: Using contours, the computer can create a list of points for each “patch” or “blob” of white in the above image. Then you can do whatever you want with these [...]

Read more