TDMS cannot handle pictures (?)

[God's Templar]

I am trying to get a VI to accept a pixmap into a TDMS file. When I connect the wires, it gives me an error: "This wire connects to a polymorphic terminal that cannot accept this datatype." Is it not possible to incorporate an image into such a file?

[Herbert Engels]

A pixmap is actually a 2D array of U32. You can save that in TDMS.

LabVIEW image clusters are not natively supported in TDMS. They can be stored by splitting them up into 3 U8 channels with "image type", "image depth" and so forth as properties. The best way of organizing the data structure would be to create a group with the 3 channels in it and store the properties to the group.

• If you store a small number of pictures (say a few hundred), you can create such a group for each picture.
  
• If you save a larger number of pictures, I would recommend using one group and appending the data fro image, mask and colors to the 3 channels in that group. You would then need an additional property that stores the length of the U8 arrays, so you can later identify each picture in these channels. This method will have better performance and a smaller disc footprint,  but requires some extra work when loading the pictures.
  

Hope that helps,
Herbert