Invoking the File :: Open menu item creates a file selection dialog . The File :: open dialog box is used to load extra-focal images, flat field images and dark images into the program. On the top left hand portion of the Dialog, you will find two text entry boxes, 1 labeled Directory and the other labeled Pattern. These two entry boxes govern which directory and which file name patterns are displayed in the scrolling list. To change directories, just change the entry in the Directory field. The Pattern field contains a regular expression which matches the desired file names, it defaults to anything ending in "fits".
Since you may load images into one of several possible destinations, loading an image is a two step process. On the right hand side of the dialog you will see a box labeled Select destination, use the radio-buttons in this box to select the destination of the image you are about to load. The extra-focal images should be loaded into image buffer 1 and 2, their ordering is unimportant provided the extra-focal distances are specified correctly. However, for convenience we will use the convention that the pre-focus image should be loaded into buffer 1.
To load an image, either double click on the file name in the scrolling list-box, or type the desired name into the entry box titled File Name and hit return.
If you load a flat field, and of a dark image, these will be applied to the extra-focal images as they are loaded. The operation performed is: Image = (Image-Dark)/Flat. Notice that the Flat field is not itself dark subtracted. If you wish to use a flat field or dark, you should load these before loading the extra-focal images. If you need to use a separate flat field or dark for each extra-focal image, load the appropriate flat and dark immediately before each extra-focal image.
You may change the search pattern for the lower (file) list box, using entry field labeled pattern just above the file listbox. You may also swap between standard Unix/(MS DOS) shell type pattern matching (globbing), or the more powerful, but more obtuse regular expression matching. This is done by selecting one of the radio-buttons marked G or R on the pattern matching line.
You may make the choice of several common file formats in this display. Within the constraints of the output format, the program attempts to format the Zernike list as a table. You may also choose between several output normalisations by using the appropriate radio button. You may also choose the export file name, and whether to overwrite or append the data to existing files. Any text that you add to the Title entry will be printed above the Zernike table.
The image output dialogs all have the following common features:
Excluding a large number of Zernike terms can result in long execution times for these operation, due to the cost of least squares fitting large number of Zernikes to the wavefront.
Using this sub-window you may save the current wavefront.
This sub-window allows you to generate a synthetic image from the current wavefront. You may select the over-sampling factor for the image, which should allow you to match the pixel scale of the synthetic image to the pixel scale of a real camera. An oversampling factor of 1, means Nyquist sampling, i.e. 2 pixels over the FWHM of the central Airy spike, or 2.44 pixels to the first Airy zero. You cannot set the oversampling less than 0.5, since this would result in loss of information. Setting the oversampling factor too high can result in a lengthy calculation time. If you need to model a very under-sampled camera, you should output a PSF with pixels some integral times smaller than the camera, then bin down the resulting image.
If you select the Add scale button, appropriately labeled axis will be placed around the image.
You may vary the tilt of the synthetic reference wavefront using the tilt slider. The scale is in total number of fringes across the pupil that you would see with a perfect test wavefront. If you set the number of tilt fringes to be Zero, the program will generate "fluffed-out" fringes. One small difference that you may see between these fringes and those from some physical interferometer, is that the reference wavefront is tilted without introducing undesirable beam shift. The angle of the reference wavefront shear may be adjusted by moving the slider. You may also adjust the wavelength for which the fringe pattern is computed.
On multi-user systems, the default location of the configuration file for additional configurations is in the users home directory. This means that each user can specify a list of private configurations which will not be seen by other users. If the default location is used, additional configurations will be loaded automatically when the program starts.
On startup the program loads configurations from the users configuration file and from the system configuration file (ef_configurations.tcl). Both of these files are plain text files, which contain tcl procedures to initialize each optical configuration. If you wish, you may use any text editor to transfer configurations from a personal file to the system configuration file. On a multi-user system you will need the appropriate permission to modify the system file. Configurations are clearly delimited by start and end comments.
If you wish to change a configuration without changing its name, just save the configuration for a second time after making the required changes. Note that the old configuration is not actually deleted, but becomes superseded by the later definition.
If you are about to start defining a new configuration, it is best to start by selecting the none configuration and building from this. If you extend a pre-existing configuration, be sure to check every entry for to make sure it is appropriate for your new configuration.
This dialog uses the same file load dialog as the Open File dialog. Use the top listbox, labeled Change directory, to select a directory. You may load a file using the lower listbox, labeled Select a file name, by double clicking on the desired file name, or by typing its name into the File Name entry and hitting return. The files shown in the select a file name listbox are filtered to match the contents of the pattern entry. You may select between simple (Globbing) name matching, or the more complex regular expression matching by selecting one of the two radiobuttons marked G or R.