Colormap for images

KNIME Extensions
1

Hi,

I need to display an image using a colormap (e.g. like the "parula" colormap in MATLAB). I guess have to transform the actual image to a label map and then use the "apply color settings to labels" node. Unfortunately I'm not sure how to transform the image to a label map where every pixel intensity is a label? Is there any node to do this automatically? Or is there any other solution for my problem? An example workflow for the solution of the problem would be very nice!

 

Thanks!

2

Hi mo,

did you try the Image to Labeling node? It should well with single channel images.

best

Gabriel

3

Hi Gabriel,

thanks for your quick response, yes, I've tried it with this node, but I am not sure how to proceed? As far as I understand, after execution of the node I do have a label map, where every pixel has a label. But this labelling is independent from the actual intensity value of the pixel, so this is not helpful or am I wrong? My output from this node is only coloured noise without actual image information. For a colormap I need to assign specific colors to specific intensity ranges, not to specific labels how can I do that? I think the color manager might be a solution but how do I apply it to the actual image data it only works for labellings? Sorry about my confusion maybe it's very simple and I'm just not getting the point ;)

best

Mo.

4

Hi Mo,

You can use the Intensity Binner node to create intensity ranges and map them to constant values before applying the Image to Labeling node.

best,

Gabriel

5

Hi Gabriel,

thanks, that works but I think it is a very complicated solution for the actual problem, especially since I have to define the intervals in the intensity binner and the colortable for the color manager manually. So this is more or less useless if you want to apply a more or less continous color model with many bins and distinct shades of colors. Do you have any better solution?

Best regards,

Mo.

6

Hi Gabriel,

solved the problem, the Color Manager offers the Range option, which I had not recognized, and binning can be performed with the Image Normalizer / Image Converter :)

 

Best regards,

Mo.

7

I am happy you found a solution that works for you, we will work on a easier solution for this in the future.

8

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