I want to get the pixel greyscale values (0-255) from the whole ROI (around 4000*200 px) to an array. I’ve tried to do this with the GetPixel function, but then program does not react anymore because of an overload. With access to the VPAT it should work more quickly, according to the helpfile. I…

Hi @mave ! As @Chris pointed out, unsafe is one of the key issues here. The keyword unsafe allows coders to use pointers very much like they did in C or C++ in C#. unsafe blocks are scoped - either by means of curly brackets {} or through function scope. In your case I think function scope fits bett…

Hi mave, According to your screenshot and the fact that you had a look into the CSVPAT tutorial, I assume you are working with C# and windows forms. The compiler errors you get are, because you have to make your method an unsafe method in order to be able to use pointer arithmetic under .NET. You…

@Chris & @illusive Thank you very much for your detailed response. That helped me a lot! Now, it works and much faster than before. It just takes around 4 seconds to export the whole Image (Mono 8Bit) to a txt file. How much faster could it be with the use of linear access? I think the requirement…

Hi Mave, [grafik] Right, its Milliseconds :muscle: Cheers Chris

Nice work @Chris :hugs: - however I’d prefer copy&pasted code over a screenshot here :wink:. And remember we’re in the C-Style API section here - can you translate the CVB.Net based code accordingly? :sunglasses: ( @mave : You’ll have to take the milliseconds with a pinch of salt because the output t…

@illusive : Homework done :sunglasses:: using Cvb; using System; using System.Collections.Generic; using System.Diagnostics; using System.Threading.Tasks; namespace ArrayTestThatActuallyWritesToAList { class Program { static void Main(string[] args) …

@Chris : There is a memory leak left: either use SharedImg or ReleaseObj to clean-up the created IMG.

Well done! I feel obliged to point out that the sequence of the pixel values in the values array does not reflect the sequence of the pixels in the area of interest due to the commendable use of Parallel.For. If the matter of the sequence in the array is of no significance for the follow-up process…

@parsd Thank you for pointing that out, I feel quite bad about that mistake as it is such a simple thing to take care of. @mave This is the point where @illusive ’s hint to use copy pasteable code takes effect as I’m not able to correct this mistake in my screenshot. However, I have edited the code…

Perfect! Thank you @Chris :blush: it takes 211 milliseconds to save it to a textfile. Thats considerably more than i needed. Thats really a great support here. Keep up with this great work :wink:

Writing Pixel Values to an Array

Programming Questions C-style API

Chris August 17, 2017, 1:34pm 5

Hi Mave,

Right, its Milliseconds

Cheers
Chris

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Writing Pixel Values to an Array

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