image with negative intensity value

[we_are_neat]

Hello, I am trying to create a VI that takes the difference between 2 different images.  I am using IMAQ subtract to do this.  The positive values in the resulting image I want to be colored blue, and the negative values I want to be colored red. 

I have 2 problems.  First of all, it seems that IMAQ subtract does not allow negative values, and truncates all differences at zero.  This is a big problem.

Second, I can not figure out how to change the color scale.  If i right click on the IMAQ display on the front panel I have a few preset options, but I want to be able to save a JPG or something with the color scale I want.

Any help here is appreciated, thanks.

[CoastalMaineBird]

Colors are handled by UNSIGNED values, because there is NO SUCH THING as a negative intensity.

A negative intensity would be sucking light OUT of your eyeballs.

In your case, you might be able to assume that any ZERO values represent pixels where the image is less intense than the reference image.

[billko]

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CoastalMaineBird wrote:

Colors are handled by UNSIGNED values, because there is NO SUCH THING as a negative intensity.

A negative intensity would be sucking light OUT of your eyeballs.

In your case, you might be able to assume that any ZERO values represent pixels where the image is less intense than the reference image.

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Awesome.  Nice post.  🙂