Aligns images graphically by interactive object selection
The basic method used is to supply a list of images and an optional reference image. The first image or the reference image is initially displayed and you are invited to mark the positions of centroidable image features on it using a graphical interface. This window then remains on the screen for reference while you identify the same features on each of the other images in the same way.
After centroiding you are then given the option to stop. If you decide to, then you will have labelled
position lists to use in the other CCDPACK routines (the labelled positions will be called
IMAGE_NAME.acc). If you choose the option to continue then a full registration of the images will be
attempted. This may only be performed for ’
linear’
transformations.
After choosing a transformation type the procedure will then go on to calculate a transformation set between all the images; this is used (with the extended reference set from REGISTER) to approximate the position of all possible image features, which are then located by centroiding and a final registration of all images is performed. The resultant images then have associated lists of labelled positions, and attached coordinate systems which may be used to transform other position lists or when resampling the data.
If the EXTRAS parameter is true you may also enter, for each of the original images, a group of images which is almost registered with it (within the capabilities of centroiding, i.e. a few pixels). In this way similar registration processes can be performed on many almost-aligned images without additional work from the user.
The graphical interface used for marking features on the image should be fairly self-explanatory. The
image can be scrolled using the scrollbars, the window can be resized, and there are controls for
zooming the image in or out, changing the style of display and altering the percentile cutoff limits.
The displayed index numbers of any identified features on each image must match those on the
reference image (though it is not necessary to identify all of the features from the reference image on
each one), and there is also a control for selecting the number of the next point to mark. Points are
added by clicking mouse button 1 (usually the left one) and may be removed by clicking mouse
button 3 (usually the right one). It is possible to edit the points marked on the reference image while
you are marking points on the other images. When you have selected all the points you wish to on
a given image, click the ’
Done’
button and you will be presented with the next one.
1 – shift of origin
2 – shift of origin and rotation
3 – shift of origin and magnification
4 – shift of origin, rotation and magnification (solid body)
5 – a full six parameter fit
6 – self defined function
[5]
If the logging system has been initialised using CCDSETUP then the value specified there will be
used. Otherwise, the default is ’
CCDPACK.LOG’
. [CCDPACK.LOG]
TERMINAL – Send output to the terminal only
LOGFILE – Send output to the logfile only (see the LOGFILE parameter)
BOTH – Send output to both the terminal and the logfile
NEITHER – Produce no output at all
If the logging system has been initialised using CCDSETUP then the value specified there will be
used. Otherwise, the default is ’
BOTH’
. [BOTH]
"
attribute=value"
type strings. The available attributes are:
colour – Colour of the marker in Xwindows format.
size – Approximate height of the marker in pixels.
thickness – Approximate thickness of lines in pixels.
shape – One of Plus, Cross, Circle, Square, Diamond.
showindex – 1 to show index numbers, 0 not to do so.
This parameter only gives the initial marker type; it can be changed interactively while the program is
running. If specifying this value on the command line, it is not necessary to give values for all the
attributes; missing ones will be given sensible defaults. ["
"
]
If USESET is false, then regardless of Set headers, each individual image will be displayed for marking separately. If the input images have no Set headers, or if they have no CCD_SET coordinates in their WCS components, the value of this parameter will make no difference.
If a global value for this parameter has been set using CCDSETUP than that value will be used. [FALSE]
’
associated with each one. "
x1008,x1009,x1010"
refndf=xmos extras=yes
continue ’
is being used as the reference image, so that will be presented first for marking
features. When you have marked features on all four images, the program will go on to
match them all up and produce a global registration, attaching a new coordinate system in
which they are all registered to each file. ’
current’
value is the value assigned on the last run of the application. If the
application has not been run then the ’
intrinsic’
defaults, as shown in the parameter help,
apply.
Certain parameters (LOGTO, LOGFILE and USESET) have global values. These global values will always take precedence, except when an assignment is made on the command line. Global values may be set and reset using the CCDSETUP and CCDCLEAR commands.
Some of the parameters (MAXCANV, PERCENTILES, WINX, WINY, ZOOM, MARKSTYLE) give initial values for quantities which can be modified while the program is running. Although these may be specified on the command line, it is normally easier to start the program up and modify them using the graphical user interface. If the program exits normally, their values at the end of the run will be used as defaults next time the program starts up.