The image above
shows the general functions available on the Alignpage. The 3 buttons
on the left are connected to the 3 steps of alignment. After loading a
set of images the "Set alignpoints" button will become available, after
setting alignpoints the "Alignbutton" will become available and after
alignment the "Limit" function will become availble. All the other
checkboxes are used to show information before or after alignment.
loading your images Alignment can be started. The alignment-process is divided into 3 steps:
- Set Alignpoints
- Limit the number of frames to be stacked
R6 allows you to set alignpoints both manually or using the "Set
Alignpoints" button, you can also mix these methods.
setting of Alignpoints is simple, you press the left-mousebutton on a
location where you want an Alignpoint and it will be set at
that point. Using the
right-mousebutton you can remove the nearestby alignpoint.
I suggest using the "Set Alignpoints" button in most cases,
this will generate a set of alignpoints ordered in "strength".
alignpoints will most likely align easier than weak
The alignpoints are selected based on the settings for minimum-distance,
free space from
the edge and the image intensity
around a possible alignpoint. The selection based on intensity around
can be done in 3 ways. Default
means an area of 48x48 pixels around a possible alignpoint is used to
estimate the image intensity, using 3x3 the
average is calculated
on very few pixels and using lowest pixel
will select on the lowest
pixelintensity in a 48x48 pixelarea. An alignpoint will only be
generated if the intensity is between the
LO-HI intensity settings.
TIP:When large black or
areas (often with planets) exist in an image using the 3x3/lowest
pixelvalue method is preferred to prevent setting of
alignpoints in dark
areas. Alignpoints should ideally be positioned inside areas that are
not too dark and with a
good amount of contrast.
"set alignpoints" you can reduce the number of alignpoints by moving the
from left to right. This will keep the "strongest" alignpoints
for alignment and disable the weaker alignpoints. The thresholdslider
remembers its position, if you however set the threshold at the weakest
position that will not be recorded to prevent the default usage of very
weak alignpoints. If you have decided
which alignpoints you want to use and you think some areas still lack
alignpoints this is the right time to add alignpoints manually. They
will be added at the bottom of the list of alignpoints.
NOTE:When you press "Set
alignpoints" again your manual placed points will be lost !
EXAMPLE: SET ALIGNPOINTS
you start the
actual Alignment you can set several alignment parameters. During the
setting of alignpoints we havent decided how large each alignmentbox
is. In V5 this was a major part of the alignment-process and
we were using
different sized alignboxes. In V6 this is not the case. The default
alignmentbox is 30 pixels, this might feel small compared to the
settings in V5 but this seems to be a good setting for the new
alignmethods. You can always change this off course, and that setting
will be your default from that moment on.
movement setting is used
to make sure that no alignpoint suddenly starts to move away from the
other alignpoints. The default of 5 means that no
alignpoint can move more than 5 pixels in X or Y direction (compared to
the other alignpoints). If an alignpoint does move more than the set
value its alignment will be set to the average movement of the other
Use Centre of
has the same functionality as in R5, during alignment the Centre of
Gravity will be calculated as an initial guess and then the normal
alignment will be calculated. The Lum-threshold for Centre of Gravity
is as in R5.
only use 2 alignpoints during alignment, you can set more alignpoints
but only alignpoint 1 and 2 will be used to estimate rotation and
WHen you press this button NO alignment will be performed and
will be directly moving to the stackingstage. This can be used
stack images without alignment, for instance to create
This allows you to set a Region of Interest, after pressing the button
a yellow box will appear on the screen. You can move and resize this
position it on the area you want to keep for stacking. If you press
"Set alignpoints" after setting the ROI the alignpoints will only be
set inside the ROI. When the ROI is visible you cannot set alignpoints
manually inside the ROI. To do this first uncheck "show ROI". The set
ROI will be kept but will not be visible. Pressing the R.O.Interest
button once more will disable the ROI.
allows you to run a
fast alignment using up to 5 alignpoints (based on the alignpoints
available). After alignment is done you will be shown the area (yellow
box) which is available on all frames. RegiStax will also automatically
generate alignpoints inside this area.
After all parameters are set you can press the ALIGN button
to start Alignment.
alignment you w
alignment you w
alignment you will
need to decide how many frames you want to keep for stacking.
RegiStax 6 there are 2 methods to do this and you can use both those
methods in a relative (%) or absolute manner. Lowest quality and
Frames/Apoint will select a number of frames for each alignpoint. If
for instance 100 frames (frames/Apoint) are selected this means that
for each alignpoint the best 100 frames (based on quality) will be
selected, the total amount of frames selected (after pressing LIMIT)
will be larger than 100. When using many alignpoints the amount of
frames selected to be stacked can be a lot larger than the setting.
using the Best Frames (% or number) option only "full"frames will be
selected. So selecting 100 will only use the 100 frames that have - for
all the alignpoints - the best overall imagequality. The
of the slider below the image after alignment is based on the setting
of the Limit-Setup.
Quality % and Best frames % will set the position of the slider to the
image with at least a quality of X % compared to the best image. In
this example a setting of 95% means that probably only a few frames
will be selected. When using the number (80 in this example) as a
selector the slider will be set to this amount of frames or less if
your sequence has less frames available.
Although the slider
is set to a position after alignment this should not stop you
inspecting the images or changing its position. If you decide that you
want to use more/less frames simply position the slider to the last
image you want to use (for best frames) or to the amount of frames you
want to use (for lowest quality and frames/apoint) for each alignpoint.
You can also change - based on the limit method choosen - the % or
number of frames using the controls in the Limit setup, changing these
will move the slider.
After setting the slider to the number of frames you want to use you can Press the LIMIT button, that will
select the frames and move you to the next stage: Stacking.