Comments by C_Johnson (Top 18 by date)

Hi Sorry I was doing a little housework re-tagging questions and I've only just found your comment. Unfortunately I can't tell you what classes do exactly what it doesn't really matter either, if you use the basic two opencv_core220.dll and opencv_imgproc220.dll you can do most simple tasks start a project with them and keep programming until you get an error asking for cvextern.dll at this point you need to add almost all of them as it looks for all of them to work. As for books on EMGU well there are none :s however there are two for opencv if you get these from a library or on-line then they can act as a guide you will hoever have to convert the code. This is easier than it sounds all cv functions are available by calling cvInvoke.FunctionName(...) hope this helps, the links for the books are: [1]http://www.google.co.uk/products/catalog?hl=en&q=Opencv+book&gs_upl=2796l4400l2l4659l7l7l0l0l0l2l199l1051l1.6l7l0&bav=on.2,or.r_gc.r_pw.&biw=1280&bih=736&um=1&ie=UTF-8&tbm=shop&cid=7984438732523221659&sa=X&ei=JrWETvn4Bo7t-gbK7ZAa&ved=0CFQQ8wIwAQ [2]http://www.google.co.uk/products/catalog?hl=en&q=Opencv+book&gs_upl=2796l4400l2l4659l7l7l0l0l0l2l199l1051l1.6l7l0&bav=on.2,or.r_gc.r_pw.&biw=1280&bih=736&um=1&ie=UTF-8&tbm=shop&cid=15231969889310013850&sa=X&ei=JrWETvn4Bo7t-gbK7ZAa&ved=0CFAQ8wIwAA

A good Image processing library you may want to try is EMGU it's a good c# wrapper for opencv it has inbuilt functions for applying gaussian filters etc http://www.emgu.com/wiki/index.php/Main_Page

Converting an integer to a double using Convert.ToInt32 is not a time efficient method. Although it does work it is not recommended, using a cast will do suffice e.g

myInt32List.Add((int)item);

This will allow the value to be directly copied to a new memory position. The reason you need to use the cast is because converting from double to a integer will cause a loss of data the cast says you accept this loss. The Convert.ToInt32 requires the data to be a transferred and operated on externally to produce the same results. In this case it is superfluous to the outcome.

I have written an article to help you and others ins setting up an EMGU project. It is available here

http://www.codeproject.com/KB/cs/EMGU_Image_Processing.aspx

I hope it helps
Cheers
Chris

Added a little to provide better support hope you don't mind Chris

None of these are references to using EMGUcv

Mainly for others if you did want to approach writing the algorithm yourself then you will need to read J Cannys paper A computational approach to edge detection available here as it is one of the most effective:

http://www.limsi.fr/Individu/vezien/PAPIERS_ACS/canny1986.pdf

Effectively what the algorithm does is examine each pixel with a set of 3x3 masks (i.e 1 pixel and the surrounding pixels) Each area is examined for edge cues at 0,90 and 45 degree angles. Effectively looking for a change in gradient. If there is a significant change in gradient (this is the thresholds you adjust) then an edge pixels is recorded as a 1 in a blank image. What you end up with is a binary map of edges. The code is not as easy as you would expect to write. On top of this you need to include a gaussian filter to remove noise and histogram analysis to further account for noise variation in pixel intensity's. As I said using existing libraries such as EMGU and openCV are far more efficient else you will be writing code again. Alternatively there is the AForge libraries that are simpler to work with but are not as advanced or powerful. See this article

http://www.codeproject.com/KB/GDI-plus/Image_Processing_Lab.aspx

Take Care

glad to see your giving it a go. Opencv is a huge library for image processing and EMGU helps port that over to c#. It can be a little tricky ensuring you have the correct .dll's in your project but when you do you will not look back.

A tip if you get any errors have a look at the what the cause is as it will tell you what dll is missing and either add that to your output folder or add it to you project as an item and set its properties to copy always.

If you get stuck then just ask me, the community here or at EMGU and we'll sort you out.

Take care
Chris

Ok the process evolved here is "edge detection" its well document however writing the algorithm out your self us unlikely to be as efficient as well used ones such as canny, prewit, roberts and sobel. Download EMGU and use there inbuilt ones:

http://www.emgu.com/wiki/index.php/Main_Page

Look at the Camera Capture and the shape example provide in the examples folder and a few of the others here's an example:

http://www.emgu.com/wiki/index.php/Shape_%28Triangle,_Rectangle,_Circle,_Line%29_Detection_in_CSharp

This is the important line:

Image<gray, byte=""> cannyEdges = gray.Canny(cannyThreshold, cannyThresholdLinking);

It's very easy to use and will be exactly what you need if you need more help please feel free to ask

Cheers
Chris

Yes your right and this method would speed up the system http://www.bobpowell.net/lockingbits.htm shows how to do this if anyone's interested. You could speed up the process further by using .NET parallel architecture using System.Threading.Tasks; and implementing a Parallel.For loop and addressing to data to a specific array location. You could also use EMGU a c# wrapper for opencv image processing library which is far more optimised than approaching this in c#. All valid solutions but I provided the simplest. Optimisation of the code can only be applied once you have code that works and I wasn't sure what code base was being worked with so please forgive the simpler answer.

Thanks I tried to see if this was the problem but it didn't work when I selected and reselected it I presume it was just a browser issue, Many thanks for reformatting it correctly - Chris

Please excuse the <pre lang""></pre> tags if they are visible as they are meant to show code blocks however something must have gone wrong - Cheers Chris

Hi, thanks I will do.

Would you mind telling me what virus checking program your running as neither Sophos, AVG or Norton can find this virus and I am deeply concerned. Could you also provide is possible the file this virus is associated with.

Many Thanks Chris