window command

This page is part of the ING document INS-DAS-29: Operations manual for UltraDAS


The window command defines the size and position of readout windows, and can also be used to disable and later re-enable the effect of a window without losing the system knowledge of the window parameters.

There are four windows that can be set, numbered 1 to 4.


    window [<camera>] <n> <image-section>
    window [<camera>] <n> enable
    window [<camera>] <n> disable
where n is the window number in the range 1..4. The image-section is in the IRAF image-section notation: [x1:x2,y1:y2] where the section includes all columns from x1 to x2 inclusive and all rows from y1 to y2 inclusive. The image sections of windows may not overlap. The image sections are define in the detector coordinate-space.


     window 1 "[501:1500,1:4200]"
Sets a 1000-pixel-wide window starting at column 501 (500:1500 would be 1001 columns wide, since column 500 would be included) and defines that window to be window 1. The previous definition of window 1 is lost.
    window 1 disable
prevents the system from applying window 1 in a readout, but causes the system to rember where the window was.
    window 2 enable
tells the system to start using window 1 again.

Notes and caveats

All four windows are defined at all times, even when they are disabled. When the DAS is newly started or newly reset, all four windows are set to [0:0,0:0] and disabled.There is no way to destroy a window; you can only disable it.

Since the windows are defined in detector coordinates (a.k.a "d-space"), it may be difficult to place windows on multi0channel devices. The geometry command runs a GUI which may help.

You can set a window that goes beyond the edge of the detector. In this case, the system fills the part with no data with zeros. If you set a window in a region of d-space which is entirely off the detector you will be warned, but the system will still accept the window. You always get images exactly as large as the windows you set up.

If you window and bin at the same time, the images are as large as the windows divided by the binning factors. That is, if you bin by a factor n on an axis you get one binned pixel for each n unbinned pixels in the window specification, and any remainder is left out of the readout. Note that the window command always works in unbinned pixels.

The window command was introduced to UltraDAS in system s9.1. The command does not work in system s8.