Start-up of HST_MASTER

 

hst_master starts with a start-up message in the terminal window. (On Windows systems the terminal window will be created automatically if necessary.) The message should look similar to the following:

           --------------------------
           WELCOME to HST_MASTER V1.5
           --------------------------

    (High-Speed Tomographic reconstruction)

           Written by Andy Hammersley

Purpose: Development, testing, and timing of CT reconstruction techniques

(Support for horizontal rotation added.)

NOTE: Display uses 'TrueColor' colour mapping with 24 bits.

At the same time a graphics window  should appear, with a similar appearance to the Figure 1, Page .

  

Figure 1: HST_MASTER Start-up

On Unix systems it is possible to get an error    message similar to the following:

Xlib: connection to "expgpch:0.0" refused by server
Xlib: Invalid MIT-MAGIC-COOKIE-1 key
WARNING: Failed to open X-11 display
WARNING: X-11 workstation not opened successfully (LG_OPEN_WK)
WARNING: There was a problem opening the graphics output window. This may be a
         problem of the X-terminal not accepting graphics output from the host
         running HST. If this is the case it can be cured by using the xhost
         program e.g. if HST is running on system 'esrf01', then enter:
         xhost +esrf01
         on the local machine which is being used as an X-terminal.

         If the problem does not seem to be linked to 'xhost' then check that
         the "DISPLAY" variable is properly defined. You can enter:
         printenv DISPLAY
         (for users of the "C"-shell or "T"-shell) to check the current
         output destination.

         e.g. If the X-terminal is called 'esrft1' then the "DISPLAY" variable
         should be set to 'esrft1:0'. To achieve this enter:
         setenv DISPLAY esrft1:0

HST exiting owing to lack of graphics

As the message explains, this is most likely to be a problem of the ``environment variable'' DISPLAY  not being properly set, or of the X-terminal not accepting graphical output from the computer where you are running hst_master. If you do not understand how to solve this problem from the message, you will need to seek assistance from a more knowledgeable Unix user.

If the graphics window opens normally, you need to click on the I ACCEPT button to enter the program.

The program then poses the following question:

  

Figure 2: Direct Reconstruction from Sinograms

For normal use, click on ``NO''. (Direct reconstruction from sinograms    requires that they have been previously created. This is normally only done when the sinograms themselves must be treated to improve data quality.)

(Reconstruction from sinograms is covered in Section 4, Page ).