different histogram in labview and matlab.

[Shredderofmass2]

Thanks,

Yes I have to save lossless. I am not sure who is at fault. Windows has no problem vewing or making thumbnails for the PNGs, but that does not say if they have been scaled to use up all the dynamic range. I do not know who is at fault. I have not decided if I need to convert all of my older data to JP2, but going forward this sounds like a suitable solution. Thanks for your help.

[wangxiaowei]

The data is scaled by a certain factor when Labview saves the data as explained in the link ("http://www.libpng.org/pub/png/spec/1.2/PNG-Encoders.html"). The scaling is done by simply left shiftting the original data by some certain number of bits, which is actually recorded in the sBIT chunk of the PNG file. So we can shift the data back. Assume the sBIT data is stored in the 42nd byte (you can easily find it with a binary file viewer), try the following code: Data = imread(FileName); fid1 = fopen(FileName); fseek(fid1,41,'bof'); offset = 16-fread(fid1,1); Data = bitshift(Data,-offset);

[Shredderofmass2]

Thanks,

I will give this a try when it comes up again.