Detector Correction Files

   

If you have selected to subtract a background image, the SELECT BACKGROUND IMAGE file selection form now appears.

When you have selected a file, the image is displayed and you are asked if the image is correct:

  

Figure 7: First Data Image Input O.K. ?

If it is not the right image, click on NO, and the file selection form will re-appear to allow you to select another file. When the image is the correct background image, click on YES.

If flat-field correction    has been selected, you will be asked CHANGING FLAT-FIELD FILE:

  

Figure 8: Changing Flat-Field File

For best reconstructed data, the experiment may have taken a series of flat-field  images evenly through the experiment. If this is the case click YES. Alternatively, if only one flat-field image was collected click NO.

Either way, you will be prompted with the file selection utility to SELECT FIRST FLAT-FIELD IMAGE. Here you should select the file containing the first (and may be only) flat-field image. This image is displayed and you need to confirm that it is the correct image.

If you have answered YES to the changing flat-field prompt, you will now be prompted SELECT LAST FLAT-FIELD IMAGE. Again the image is displayed and you must confirm that the correct data has been found.

For changing flat field sequences the COUNTER INTERVAL BETWEEN NEW FLAT-FIELD FILES is now requested. This is number of data files which are input between flat-field images. e.g. If a new flat-field image has been taken every 100 projection images, then this number should be set to 100, and the flat field images should be numbered 100, 200, 300, etc.