RGB Overlaying Multiple Images For Auger Data Processing

swm88er
Posts: 4
Joined: 2016-01-11
Location: United States

I have successful imported some Auger maps that into igor (in the form of 2D waves). However I am struggling to figure out how to make each image a different color and then overlay them into one single image, so that it looks something like the attached image. Please let me know if you know how to do this. I think that imageblend should work but I an struggling with the fact it must be a 3D wave. Can you make transparency information the third dimension somehow? Thanks!

Auger map where three different images were combined into one with an RGB overlay

olelytken
Posts: 44
Joined: 2015-10-12
Location: Germany

A 2D wave is a black and white image. To make it a colour image you need three channels: red, green and blue. That's why you need a 3D wave: the 3rd dimension will be the red, green and blue layers. I assume you just need to convert the black and white 2D wave into a 3D RGB wave and select the colour you want for that Auger peak, before you ImageBlend all the RGB waves.


JimProuty's picture
Posts: 579
Joined: 2007-07-19
Location: United States

olelytken wrote:
A 2D wave is a black and white image. To make it a colour image you need three channels: red, green and blue. That's why you need a 3D wave: the 3rd dimension will be the red, green and blue layers. I assume you just need to convert the black and white 2D wave into a 3D RGB wave and select the colour you want for that Auger peak, before you ImageBlend all the RGB waves.

That's not completely accurate: 2D Matrices typically are *interpreted* as black and white when the values in the matrix are only 0 and 1.

Normally the values encompass a larger range, say 0-255 or even -Infinity to +Infinity if floating point data, in which case the value is often mapped to a color from a selection of colors (a "color table"), resulting in an image plot called a "false color plot".

That's the normal Igor image plot that defaults to the Grays color table.

--Jim Prouty
Software Engineer, WaveMetrics, Inc.


JimProuty's picture
Posts: 579
Joined: 2007-07-19
Location: United States

swm88er wrote:
I have successful imported some Auger maps that into igor (in the form of 2D waves). However I am struggling to figure out how to make each image a different color and then overlay them into one single image, so that it looks something like the attached image. Please let me know if you know how to do this. I think that imageblend should work but I an struggling with the fact it must be a 3D wave. Can you make transparency information the third dimension somehow? Thanks!

Use either Igor 6's ImageBlend (which blends RGB images), or with Igor 7 you can also overlay 4-layer 3D waves, where the 4th layer is alpha (transparency).

You can convert a 2D image to RGB using ImageTransform/C=M_Colors cmap2rgb

after creating the M_Colors using ColorTab2Wave, then using SetScale x to encompass the range of values in the 2D wave.

--Jim Prouty
Software Engineer, WaveMetrics, Inc.


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