This page gives a brief description of how to use the FIGDISP window for display and analysis of images. The FIGDISP/GUI control window is depicted below.

Common Operations

Zooming and Panning

Zoom
Click the IN button on the GUI to zoom in, and click OUT to zoom out. Click NORMAL to reset the zoom to its nominal value.
Pan
Click CENTER to re-center the window on the image. Click the left mouse button in any window (except the pixel values window) to move the point under the cursor to the center of the main window.

Colormap Adjustment

Scaling algorithm
Click LINEAR for a linear colormap, or HIST EQ for a histogram-equalized colormap (which usually gives the best result). The AUTODISP and MANUAL buttons are not often used.
Contrast adjustment
After clicking the PAN/COLORS button, click and drag the right mouse button to adjust contrast (vertical motion) and brightness (horizontal motion).
Reverse video
Click the REVERSE VID button to invert the colormap.

Line Graphics

Row plot
Press the r button to plot the row under the cursor. Press comma button to increase the numbers of rows to average (default is 1), and press period button to decrease.
Column plot
Press the c button to plot the column under the cursor. Press comma button to increase the numbers of rows to average (default is 1), and press period button to decrease.
Vector plot
Click and drag the middle mouse button to plot pixel values along a vector.

Pixel Values

Local
Click the TITLE BAR DISP button and move over a pixel to have its location and value displayed in the window titlebar.
Regional
Press the p button to pop up a window listing pixel values within a 10×10 pixel region centered on the current location.

Statistics

Centroid/FWHM
Center the cursor over a star and press s to pop up a window displaying the measured centroid and FWHM in column and row space.
Min, Max, Mean, Sigma of region
Click on the STAT BOX button, then move cursor onto image. Define a rectangular region by clicking the left mouse button to define the upper left corner, and the right mouse button to define the lower right corner. A window will pop up and display the mean, minimum, and maximum values within the region, plus the standard deviation (sigma).

Key Bindings

The following keys are defined:

FIGDISP Key Bindings
Key Function
Z Zoom in
a Go to normal zoom factor
z Zoom out
X Zoom in X coordinates
x Zoom out X coordinates
Y Zoom in Y coordinates
y Zoom out Y coordinates
H Help (display list of key bindings)
v Toggle cursor display (Pixel location/ADU's)
o Recenter image
l Toggle display of panner window (a la SAOimage)
Q Quit
L Show a window containing the color map
p Toggle display of pixel values near the cursor
r Produce a row plot in the line graphics window
P Print the image
V Print the visible portion of the image
i Toggle color map inversion
s Toggle display of centroid/FWHM window
c Produce a column plot in the line graphics window
comma Decrease number of pixels averaged for a line plot
period Increase number of pixels averaged for a line plot
slash Reset number of pixels averaged for a line plot
! Toggle function key inhibiting
< Decrease number of times LUT entries are recycled
> Increase number of times LUT entries are recycled
? No longer use LUT entry recycling
e Cycle through display scaling algorithms (histogram equalization, autodisp, normal)
m Toggle between PAN/COLORS and STAT BOX modes
S Print image statistics within box


Notes:

All windows except the location window may be resized arbitrarily. The location window can be resized within limits, and the program will often adjust the user defined size. The line graphics window should not be resized while it is being modified.

``p'' or ``s'' pressed in the main window or in the location window will cause the pixel values or seeing window to appear. The window may be dismissed by the same button inside that window. All other functions work from all windows (``Z'' always zooms in).

No transformations (zoom, resize window) will move the point at the center of the window, unless that would cause the entire window to be empty.