output of DigitizerProjectionActor

[CIRCLE2096]

I’m using the DigitizerProjectionActor to simulate a CT scanner, but I’m confused about the mhd/raw output.

I’ve looked at the example in Test028 for the SPECT system, where the DigitizerProjectionActor is used after the DigitizerEnergyWindowsActor (as seen in the add_digitizer_tc99m function). The DigitizerEnergyWindowsActor produces several output keys, such as PostPosition_X, TotalEnergyDeposit, and GlobalTime.

However, the raw file output from the DigitizerProjectionActor is a matrix with a shape like (500, 500, 1), containing just a single float value per voxel. I couldn’t find a clear explanation of this value in the documentation, and after reviewing the source code, I only found that the DigitizerProjectionActor works by mapping the hit positions to image indices.

The image seems to be displayed as a grayscale image, so I’m wondering how that value is computed. Pls help.