Applying a sketch or brush stroke effect to an image

I already offer a Sepia Effect for images uploaded to a site using something like this:

    Dim SepiaMatrix As New ColorMatrix(New Single()() {
     New Single() {0.493F, 0.349F, 0.272F, 0, 0},
     New Single() {0.769F, 0.686F, 0.534F, 0, 0},
     New Single() {0.289F, 0.168F, 0.131F, 0, 0},
     New Single() {0, 0, 0, 1, 0},
     New Single() {0, 0, 0, 0, 0}})
    ...
    Attributes.SetColorMatrix(SepiaMatrix)
    ...
    Gfx.DrawImage(Image, New Rectangle(0, 0, Image.Width, Image.Height), 0, 0, Image.Width, Image.Height, GraphicsUnit.Pixel, Attributes)

I'd also like to offer a brush and sketch effects [Edit: That is to say that when a photo is uploaded, my app applies filters to the photo in such a way it looks like either brush strokes or crosshatching and "drawn" lines - Exactly like an artists sketch. ]

I've seen This Question but it's not very clear what the solution is and I'd prefer not to have to install a Java IDE and go crawling through the very advanced/flexible Java library mentioned.开发者_如何转开发

Can someone provide a link to a good tutorial (.Net 3.5+ by preference but any language at all will do) or provide me with a basic list of steps I need to apply in order to achieve my goals.

I once found a Wiki with detailed step-by-step image manipulation in PHP but haven't been able to find it since. If anyone knows of it, I believe it had an example of a sketch effect. The site used a predominantly blue image of a planet in space as the test case.

Many thanks for your help.

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The aForge project is an open source set of libraries that does imaging filters (alongside many other things). They have a filter for Oil Paint (not exactly what you asked for, but it will be instructive: http://code.google.com/p/aforge/source/browse/trunk/Sources/Imaging/Filters/Other/OilPainting.cs . As well someone has created a PencilSketch filter based on the aForge library, and you can see it's source code here: http://blendfilter.codeplex.com/SourceControl/changeset/view/67619#1218773 .