ISOCAM Interactive Analysis User's Manual Version 5.0 - ISO - ESA

132 CHAPTER 14. IMAGE ANALYSIS AND DISPLAY
Mean
The selected region in the Frame Window can be a rectangle. In this case, it is the sum
(or the mean) of the intensity of the pixels of this region which is plotted versus time in the
Plot Window. This can be useful when you have an observation with a pixel field of view of 3
arcseconds and some jitter: you sum over a region containing the source.
You can also select a range of indexes, the displayed image will be the average over this range.
14.4.4.2 Example
CIA> old_raster = raster
CIA> deglitch, raster, method=’mm’
CIA> {\bf xcube}, raster, old_raster
>> click in the Plot Window, to select one image
>> click in the Frame Window on a masked pixel
>> if needed type new values in the "Min/Max" text widgets of the Plot Window
>> click on the "pixel" button
>> click on the button "File", then select "Quit"
14.4.5 Cube analysis with x3d
x3d is a widget-based program specifically for analysing cubes of images. x3d is started by
calling it on the CIA command line with an IDL cube or a PDS as input. If the input is a
PDS then the data in CUBE and MASK are loaded. Optionally, the CUBE and MASK can be
explicitly specified as the first two arguments. An example call is:
CIA> x3d, cvf_pds
The x3d window (Figure 14.9) displays the current image from the cube being investigated.
The current image is changed by either clicking on the buttons (next frame and previous frame),
or by moving the slider bar to scroll through the cube. A plot window displays either the
temporal history of the current pixel, a horizontal cut of the row of the current pixel or a
vertical cut of the column of the current pixel. The current pixel is changed simply by clicking
on the image and the type of plot displayed in the plot window is changed by choosing one of
the buttons: temporal cut, horizontal cut or vertical cut.
If the x3d input is a PDS, or the CUBE and MASK are explicitly supplied, then the masked
pixels in each image of the CUBE may be viewed. Clicking on the button mask will activate
this feature. In the plot window, all the masked pixels will be marked with an +, and in the
image display window, masked pixels will not be displayed, i.e. will show up blank in the image.
A newly added feature of x3d is the button glitch – see Section 14.4.6.
14.4.6 x3d as a calibration aid
x3d is an excellent tool for examining cubes of CAM images and looking at the temporal and
spatial behaviour of a pixel in a CAM observation. It can even perform manually deglitching.
This makes it a very useful calibration aid. To preform the functions described below x3d should
be given a PDS or a CUBE and MASK as input.
• Dark correction: In a PDS that has not been dark corrected, a regular pattern of dark
and bright lines are apparent in the IMAGEs in the CUBE. When viewing the CUBE with
x3d, click on the button vertical cut to display a plot of pixel intensity against image line