Issue with ImageLoad for .png files on a Mac

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Thu, 08/09/2012 - 05:59 pm

I've written a procedure to generate a histogram of all the gray levels. It's important that I get an accurate read of the exact gray level in the .png files I'm using. So, I'm testing the procedure on some small, square images of uniform gray level.
When I import the file into Igor using the "ImageLoad" function, and examine the wave, the wave values are not the expected values. For example, I create the square so that each pixel contains a uniform gray (R=G=B=200, out of a scale of 0-255). When I open the image in Mac Preview and use the Digital Color Meter utility, it tells me that the RGB levels are as expected.

When I import the image into Igor Pro with the ImageLoad function and examine the wave, I find that all of the entries are some lower number (for the case of RGB=200, the imported 3D wave has all values equal to 188). I find that this is a consistent problem across all gray levels.

I'm at a loss as how to proceed. Anyone have any suggestions?

Thanks

doctorZZ
This issue has been resolved on the phone. Indeed rpng is the answer.

A.G.
WaveMetrics, Inc.

August 14, 2012 at 02:42 pm - Permalink