In addition, the IMS option assumes that both the simulated image and its object file have the same number of pixels. For example, if the input object file is 1000 x 1000 pixels, the IMS simulated image is also 1000 x 1000 pixels. However, if your detector has only 100 x 100 elements, the simulated image should also have 100 x 100 pixels. To map the IMS result onto the detector, the input to each detector element should be based on the average brightness and color over a region of 10 x 10 object-file pixels. To correctly represent the real detector blurring, you must downsample the IMS result of 1000 x 1000 pixels down to 100 x 100 pixels.
To produce an image with correct detector blurring, a macro can be used to conduct post-processing on the IMS output data file. Here is an example that you can try using the macro downsample.seq.