posts

3D Additive and Subtractive Color model

Nov 27, 2021 color

The color theory defines two common color models: Additive and Subtractive.
The interactive visualisation below shows the mixing of each primary component in the additive and subratctive color models. Drag to rotate, scroll to zoom the layers.

How to use Serial Port from WSL using minicom

Nov 14, 2021 windows-wsl serial-port ubuntu

The COM port number enumerated from Windows is needed in WSL

QT - Dark window based on Windows 10 theme

Oct 24, 2021 qt cpp windows-10

Qt directly doesnt support Dark/Light theme from Windows 10. This is a workaround.

How to reset Windows WSL user password

Sep 29, 2021 windows-wsl password-reset ubuntu

The WSL Linux password can be reset easily with below steps:

PDF to Word in terminal

Sep 1, 2021 linux-command pdf utils

Quick way to convert pdf to word document from terminal. Works mostly fine in layouts.

C/C++ Jupyter Notebook using xeus-cling - Windows WSL Setup

Jun 27, 2021 jupyter-notebook cpp

Jupyter notebook supports C/C++ using the project. xeus-cling is a Jupyter kernel for C++ based on the C++ interpreter cling and the native implementation of the Jupyter protocol xeus.

extract pdf attachments in ubuntu

May 26, 2021 pdf utils

PDF files can often come with embedded file attachments. In Windows Adobe reader can extract this easily. In case of ubuntu, the handy command line utility pdftk can help:

Animating homography

Apr 26, 2021 opencv homography perspective-transform

A trick to animate the perspective transformation between two planes. The homography matrix is a 3x3 matrix computed from point correspondence.

Equirectangular to Tiny-planet

Apr 17, 2021 ffmpeg tinyplanet equirectangular geometric-transform

Named Tiny planet, Little planet etc are beautiful effects that converts the projection of an equirecangular image.

Encode YUV/NV12 to PNG using libav

Apr 17, 2021 YUV libav image png

Encode a YUVNV12 to PNG using libav

Homography

Apr 8, 2021 opencv camera image homography

Math is beautiful when not seen as just equations. Homography is one of the beautiful concepts in planar geometry. Lets consider a physical point P\(( x, y)\) is represented in two different images as \(( x_{1}, y_{1})\) and \(( x_{2}, y_{2})\).

Chroma Sub-sampling

Mar 1, 2021 color video YUV

YUV 4:4:4 YUV 4:2:2 YUV 4:2:0 … ?

A grep for pdf

Feb 27, 2021 utils pdf

Grep in pdf text

GLSL - Vignetting

Feb 27, 2021 opengl shaders glsl

A simple example of vignetting in GLSL

OpenCV - Crop Image

Feb 27, 2021 opencv

How to Crop an OpenCV Mat on specific co-ordinates

OpenCV - YUV NV12 to BGR conversion

Dec 11, 2020 opencv

How to convert an nv12 buffer to BGR in OpenCV, C++

IPC in Linux - an Intro

May 30, 2012 IPC linux

In this article author began to see how multiple processes may be running on a machine and maybe be controlled (spawned by fork()) by one of our programs. In numerous applications there is clearly a need for these processes to communicate with each exchanging data or control information. There are a few methods which can accomplish this task.