1.1 HOW-TO Inspect
This HOW-TO deals primarily with image inspection methods. Other
inspection routines are described in their relevent sections
(see, e.g., http://www.astro-wise.org/portal/howtos/man_howto_qcastrom/man_howto_qcastrom.shtmlastrometry inspection and http://www.astro-wise.org/portal/howtos/man_howto_zeropoint/man_howto_zeropoint.shtmlphotometry inspection)
These and other inspection routines may eventually be linked from this HOW-TO formally, but they will never be described in any detail here.
Image inspection takes place primarily a MatPlotLib (PyLab) window and is
illustrated in figure . The plot contains a representation
of the image with a title containing the filename of the frame being inspected.
There are also pixel coordinate indicators for convenience. As this plot is
within a Pylab window, all the familiar manupulation routines are available
(e.g., panning, zooming, etc.) In addition to these, there are some single-key
commands to create new plots that illustrate specific details around the cursor
position. The next section gives details on these.
Figure:
A typical image inspection window without the PyLab controls.
|
Image inspection can be called from any BaseFrame-derived frame,
and is called by executing the frame's inspect() method:
awe> frame = BaseFrame(pathname='filename.fits')
awe> frame.inspect()
There are also a large number of options to control how the plot looks and even
what is plotted. A summary of the options is given below:
- pixels:
- optional list or array representing the image to be inspected (can be MxN for
greyscale, or MxNx3 for RGB)
- zone:
- tuple of (x0, y0, x1, y1) representing the image coordinates of the two
oposing corners of the sub image to consider
- kappa:
- the factor by which the dynamic range is increased in units of sigma (0 gives
full range)
- iterations:
- number of iterations in the kappa-sigma range clipping
- cmap:
- PyLab color map instance
- vmin:
- lower display range in native units (e.g. ADU)
- vmax:
- upper display range in native units (e.g. ADU)
- interpolation:
- type of interpolation the PyLab viewer uses (nearest, bilinear, etc.)
- width:
- width of the PyLab figure window (in inches)
- ratio:
- ratio by which to scale the figure height (default: x_dim/y_dim)
- viewer:
- external viewer to use in case the image is too large
- force_viewer:
- always use the viewer
- subplot_size:
- width and height in pixels of region of interest
- contour_levels:
- number of contour levels for the contour plot of the region of interest
- num_bins:
- number of bins in the histogram plot
- extension:
- extension of the filetype to save plot to (png, ps, or eps) None disables
saving
- compare:
- compare this frame to its previous version using difference imaging
(current-previous), pixels is ignored
- level:
- depth of query for previous version (0 goes as deep as possible) when compare
is True
- other:
- a second of the same type of Frame object to replace previous when compare is
True (if color is True, other can be a list of two images)
- clip:
- kappa-sigma clip each image prior to subtraction when compare is True
- color:
- use color combining (RGB) instead of differencing when compare is True (kappa,
vmin/vmax only honored when clip is True), this image is R, other is B if
single, other is [G, B] if it is a list (EXPERIMENTAL)
Also, there are a number of commands that work on an area around the current
cursor position. A summary of these commands are given below:
- q
- closes the most recent plot window when pressed in the main window
- SPACE
- displays the X and Y coordinate (FITS standard unit indexed) and the count
level
- a
- performs aperture photometry on brightest feature in the region of interest
(NOT YET IMPLEMENTED)
- c
- displays a contour plot of the region of interest (see contour_levels)
- h
- displays a histogram of the pixel values of the region of interest (see
num_bins)
- r
- displays a radial plot of the brightest feature in the region of interest
- w
- displays a wireframe plot of the region of interest
- p
- displays profile plots in both X and Y dimensions versus intensity (count
level)
Please see the inspect docstring for more details and current details on
both of these:
awe> help(frame.inspect)
A display method is available for all frames:
awe> frame.display()
This will open up the frame in skycat, by default.
page generated Tue Nov 21 10:29:30 CET 2017