# Stefan Karlsson

### Halmstad University

Post doc in Image analysis/computer vision/biometrics

Professional Interests: signal processing, biometrics, image analysis, computer vision

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**12** Answers

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CONTRIBUTIONS**8** Files

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ALL TIME DOWNLOADS**55007**

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**Content Feed**

Submitted

Tutorial and Toolbox on real-time optical flow

Code with visualization and excercises. Camera supported

8 maanden ago | 17 downloads |

What frustrates you about MATLAB?

I miss the ability to define your own workspace. When doing event driven programming in Matlab, there are 3 ways to share your o...

meer dan 4 jaar ago | 0

Submitted

FancyFlowPlayer

Video Player with visualization and interactive reading.

meer dan 5 jaar ago | 1 download |

Submitted

Interactive Incompressible Fluids (Karlsson version)

An interactive demo of Navier-Stokes equations for incompressible fluids.

meer dan 5 jaar ago | 1 download |

Global workspace usage for efficiency?

Walters good points above are not an answer to my question. Let me try to give my point of view on this, and then anyone can fee...

meer dan 5 jaar ago | 0

Question

Global workspace usage for efficiency?

*Are there cases when using global variables is the most efficient implementation?* I hate using the global workspace, but I ...

meer dan 5 jaar ago | 2 answers | 0

### 2

answersCan I use PCA effectively on a greyscale image?

... I guess one can also give another piece of advice to anyone who stumbles onto this looking for info on PCA. Read the posts b...

meer dan 5 jaar ago | 0

Can I use PCA effectively on a greyscale image?

I think the answer by Walter, while technically correct, confounds a VERY simple topic. Being technically correct here amounts t...

meer dan 5 jaar ago | 0

Scale a mask in an image

use imresize. If you use it with interpolation 'nearest', you have your functionality in a single line. If you use another inter...

meer dan 5 jaar ago | 1

Submitted

Real time optical flow, and video processing

Real time optical flow, and video processing, with support for camera input in Matlab.

meer dan 5 jaar ago | 6 downloads |

timer and Interruptible=Off button callback priority/preemption?

Sometimes I get into the problem that I am in a function that is not interuptible. An ugly work-around that seems to work (o...

bijna 6 jaar ago | 0

Save data X over Y

Poorly asked question. Do you get 2 new X and Y matrices by regular intervals, or is time-dependency something represented by t...

bijna 6 jaar ago | 0

Which way is correct of defining function...I am getting two differnt surfaces if I specify same equation differently...?

There are 2 interpretations of your shared code (i.e. two ways i see that you would be able to run it without error). 1. you ...

bijna 6 jaar ago | 0

| accepted

GUI figure focus

Seems this is still an issue, here is my solution quick fix: %takes any active uiobject as input, and returns keyboard fo...

meer dan 6 jaar ago | 0

Submitted

Visual Studio Toolbar for mex interface with video tutorial

Seamless interface, VS 2010 and 2012 and Matlab for MEX. Video linked to step you through.

bijna 7 jaar ago | 3 downloads |

What frustrates you about MATLAB?

topping the wish-list: 1. A "beep off" that actually works, stops Matlab completely from making the OS beep sound. 2. A sh...

ongeveer 7 jaar ago | 0

Solved

Swap the first and last columns

Flip the outermost columns of matrix A, so that the first column becomes the last and the last column becomes the first. All oth...

meer dan 7 jaar ago

Submitted

Optical Flow with Matlabs Computer vision toolbox

optical flow on camera, synthetic video and video files

meer dan 7 jaar ago | 3 downloads |

Solved

Make a checkerboard matrix

Given an integer n, make an n-by-n matrix made up of alternating ones and zeros as shown below. The a(1,1) should be 1. Example...

meer dan 7 jaar ago

Solved

Find all elements less than 0 or greater than 10 and replace them with NaN

Given an input vector x, find all elements of x less than 0 or greater than 10 and replace them with NaN. Example: Input ...

meer dan 7 jaar ago

Solved

Triangle Numbers

Triangle numbers are the sums of successive integers. So 6 is a triangle number because 6 = 1 + 2 + 3 which can be displa...

meer dan 7 jaar ago

Solved

Determine if input is odd

Given the input n, return true if n is odd or false if n is even.

meer dan 7 jaar ago

Solved

Column Removal

Remove the nth column from input matrix A and return the resulting matrix in output B. So if A = [1 2 3; 4 5 6]; and ...

meer dan 7 jaar ago

Solved

Select every other element of a vector

Write a function which returns every other element of the vector passed in. That is, it returns the all odd-numbered elements, s...

meer dan 7 jaar ago

Solved

Find the sum of all the numbers of the input vector

Find the sum of all the numbers of the input vector x. Examples: Input x = [1 2 3 5] Output y is 11 Input x ...

meer dan 7 jaar ago

Solved

Make the vector [1 2 3 4 5 6 7 8 9 10]

In MATLAB, you create a vector by enclosing the elements in square brackets like so: x = [1 2 3 4] Commas are optional, s...

meer dan 7 jaar ago

Solved

Times 2 - START HERE

Try out this test problem first. Given the variable x as your input, multiply it by two and put the result in y. Examples:...

meer dan 7 jaar ago

Submitted

VideoResize

A MUCH faster version of "imresize", specifically for videoprocessing

meer dan 7 jaar ago | 2 downloads |