NAME:
    it_init
 PURPOSE:
    Itool initialization.
 DESCRIPTION:

    The contents of the image parameter structure is:
      These usually come from image header information.
        airmass  - float,  airmass of image
        date     - string, UT date of image at start
        exptime  - float,  exposure time of image in seconds
        expdelta - float,  time between frames in seconds for image cubes
        filter   - string, filter used for image
        imfile   - string, name of file where image came from
        jd       - double, Julian Date of middle of exposure for image.
        object   - string, Descriptive name of object
        ut       - string, UT time of image at start

        xsize    - int,    width of image(s) in pixels
        ysize    - int,    height of image(s) in pixels
        nframes  - long,   Number of frames in image cube
        imageptr - Pointer to image cube

        asis     - boolean array
                     false --> call autostrech computer, if NOT ready, then
                               scl is computed and set to cur, if ready, then
                               there is no change.
                     true  --> cur is valid, use it.
        autophot - int,    Flag, set when auto photometry requested.
        frame    - long,   Current frame being displayed
        curmin   - float array, actual display min
        curmax   - float array, actual display min
        lastfwhm - float, Last FWHM of object or anchor object
        lastmag  - float, Last magnitude of object or anchor object
        lastpos  - intarr(2), Last photometry position
        lasttype - int, type of last click 0=none, 1=left, 2=right
        minvalue - float array, minimum in each frame
        maxvalue - float array, maximum in each frame
        ready    - boolean array, true --> autoscale values are valid
        sclmin   - float array, autoscale display min
        sclmax   - float array, autoscale display max
        title    - string, name for structure
 CATEGORY:
    Compound Widgets
 CALLING SEQUENCE:
    it_init, image, im_parms
 INPUTS:
    image : The image array.
 OPTIONAL INPUT PARAMETERS:

 KEYWORD PARAMETERS:
 OUTPUTS:
    im_parms : The image parameters structure.
 OPTIONAL OUTPUT PARAMETERS:

 COMMON BLOCKS:

 SIDE EFFECTS:

 RESTRICTIONS:

 PROCEDURE:

 MODIFICATION HISTORY:
    Written by Doug Loucks, Lowell Observatory, July 29, 1994.
    1996 Jun 24, MWB, added items for automatic photometry operation