New
Limovie 0.9.25d has been released (Mar.3 2007)
New Features:
Gamma
Reverse Correction
This function is the filtre to add the
gamma correction to bmp image.
(1) Click “Gamma Reverse
Correction” check box and check it.
(2) Input the gamma
value which is considered to be added by video camera.
eg. Watec
WAT100N :
Gamma Hi:0.45 Lo:0.60 OFF:1.0 ..... If the switch is
selected Hi then gamma value 0.45 should be input.
(3) Then, the
image is changed to gamma corrected. You can confirm the result of
this effect using 3D graph function.
(4) Addition to, the
Limovie's photometry works using this image, therefore the result of
photometry is also “gamma corrected”. This means that
videos pictured with gamma correction added by camera.
Notice:
The
pixel value (ADU) is decrease by this filtre. When measuring a faint
star, the measurement region of Limovie may be difficult to track the
target star. In such case, set the threshold to large value.
Fixed
bugs:
“The coordinate of x and y recorded into
CSV-file was incorrect” was fixed. (The problem was in only
ver. 0.9.25)
“The central event time was incorrect”
was fixed. (The problem was in only ver. 0.9.25)
“The anchor
mode of star tracking doesn't work correctly” was fixed.
Using Limovie 0.9.25
Limovie Ver.0.9.25 has been released. This version has several new features to analyze the event time and light curve more accurately..
1.Using
with Avisynth
Limovie
became possible to read long video clip recorded as AVI Type1
file.
Thanks: Steve Preston discovered this useful method.
2.Multiple
Object Measurement
This
version is able to measure three objects simultaneously. It can be
used to examine the influence of the scintillation of the atmosphere
etc.
Thanks : Tony George suggested this function and checked this
program.
3.Load
CSV file
It can
re-analyze CSV file.
4.Graph
Draw
Spread sheet is
not necessary for viewing the light curve any longer.
5.Fitting
the light curve to diffraction simulation
This function
gives accurate time, and
inclination of lunar limb.
Thanks: Tsutomu Hayamizu checked this
article and gave useful suggestion to explain more accurately.
6.
Gamma Reverse Correction
This
function is the filtre to add the gamma correction to bmp image.
Using with Avisynth
Limovie
has limitation of “280 seconds” about the length of video
clip.
Steve Preston had discovered the method to solve this
issue. That is using Limovie with Avisynth.
He discribed how to
use Avisynth on his website.
Using Avisynth with LiMovie : Steve Preston's website. There is mentioned detail of this method.
It is significant advance of Limovie. The method is possible to analyze long time video clip and also possible to read avi file which is compressed by DV codec. Dave Herald suggested the way to use Avisynth more easily. He said “I wonder ... have an option to read an avi file using Avisynth - with Limovie doing the necessary handling to avoid having to create a batch file each time.” Then, I improve Limovie to make .avs file automatically.
To read image by AviSynth, you must check the check-box of Use AviSynth in the "Update Setting Items". Please do this at first.
In environment which already installed AviSynth. The operation is same as previous version for usual file loading. When .AVI-file is selected by dialog box, Limovie makes AVS-file which has same filename as AVI-file, in the same directory as the AVI-file. And Limovie read .AVS-file automatically.
eg.
Obtain
video file name : observation.avi
-> Make .avs file :
observation.avs
-> Read video file (observation.avi)
If you want to edit .AVS file, Click "AVS File Edit" in "Option" in the main menu. It will be able to edit for your purpose, and it will be able to save it with arbitrary name.
Multiple
Object Measurement
This
version can measure three objects simultaneously.
Tony George
suggested this function to know the influence of cloud or poor
transparency etc. to compare other stars or sunlit point on the moon.
To add the new measurement region, please operate it as
follows.
(1)
Clicking right button on _another_ target star.
(2) Click "ADD
Object" in popup menu.
(3) New measurement region is
high-lighted, and it will be able to re-set its position by
left-click on the target star.
(4) And it can be selected using
Object1,2,3 button in the right of control area.
Graph
Draw
This
function is made to obtain the event time more easily.
When it is
done clicking Start and Stop button of measurement, then click Graph
button. The graph window drawn the lightcurve will be appeared. If
multiple target is measured then multiple lines are drawn.
Find
the point which indicate the central time of event( it has 25%
intensity of full bright of target star ).
Clicke the point, then
the image of video frame is changed to relative frame.
You can
read the time of centre of event easily usinfg Field Show button.
Load
.CSV files
This is the function possible to re-analyze the previous measurement. Especially, it does not need to spend your time to measure the long video clip.
Click [Load CSV] button and select the .csv file. Limovie load the data of previous measurement with reading the video clip (.avi file).
Graph
function & Diffraction Fitting
If you have a video
tape recorded grazing occultation event, operate as follows. The
operation can be also used similarly at the case of general
occultation and asteroidal occultation.
1. Click
[AVI File Read] button
Select the .AVI clip and execute
loading.
2. Click
the target star on the image area
It will centre the
measurement region on the target star.
3. Click
[Start] button
Measure the entire of video clip if possible.
4. Save
.CSV File
I recommend to save the .CSV file into same
directory as .AVI file.
It will be able to load this file again
when the program is re-started.
5. Click
[Graph] button
The graph window drawing light curve is
opened.
It display entire video clip.
6.Find the
point of occultation event
Look
at the graph and find the point which indicate the time of event.
Click the point. Then, the point is turned to red. And it is
selected as a base point for diffraction fitting.
If you want to
reset the selection, click the point again.
7. Click
[Part] button
The scale
of X-axis is stretched. And the selected point is moved to the centre
of graph.
And Click [Scale] updown button.
The scale of X-axis
is expanded or reduced. I recommend to set to 4-16.
8. Click
[Diffraction] button
The
window of Fresnel Diffraction Analyzing is opened.
9. Set the
lunar(asteroid) distance
#
If you do not need to obtain the data of the contact angle, this
setting is unnecessary.
Lunar distance is predicted by LOW(Lunar
Occultation Workbench.)
Notice: Limovie
needs the observer centric distance to calculate the diffraction
effect. However, it is thought the numerical value obtained from
prediction software is a geocentric distance. It can be used as an
approximate value.
For
asteroidal occultation
It
can be obtained simply using the value of “Parallax”
described to Steve Preston's prediction.
Distance = Radius
of Earth / (Parallax(rad))
eg. Parallax=4.728" =
0.001313(deg) = 0.00002292(rad)
Distance = 6,378[km] /
0.00002292[rad]) = 278,200,000[km]
10.Set the
lunar velocity
# If you
do not need the data of the contact angle, this setting is
unnecessary.
This is speed of shadow of lunar passed on the plane
which is perpendicular to the direction of target star.
In grazing,
this is obtained by the method as follows.
*
IOTA prediction contains lunar velocity eg.
LUNAR VELOCITY: 1.621
DEG. OF POSITION ANGLE/MIN.
This velocity is displayed as
position angle of circumference of lunar.
It is able to convert to
[m/sec] as follows.
V = R * Pi * LV / (180 * 60)
V : lunar
velocity [m/sec]
LV: lunar velocity [position angle/min]
R :
lunar's radius [=1738000m]
Pi: pi [=3.14159...]
*As an
example:
V=1738000*3.14159*1.621/10800=820m/sec
In the case
of general lunar occultation
*OCCULT
or LOW predicted "Radial Velocity(RV)".
It means the
speed of change of diffraction effect.
If there is large angle
between lunar limb and lunar direction, the lunar shadow, which has
various density, is changed slowly.
The change speed slows in
proportion to 1/cos(C.A.). (C.A.:contact angle)
Lunar Velocity
which is requested by Limovie is at the case of "contact angle =
0", and also it is necessary to input contact angle to the edit
box. However, it can be substituted by writing the “Radial
Velocity" in the "Shadow Velocity" box. You need not
write anything about the angle. (The angle is considered as 0.)
*
As an example..
Radial Velocity(RV) = 0.396 "/sec
Lunar
Distance(LD) = 378000km
Shadow Velocity(SV)
SV = LD * Pi * RV
/ (180 * 3600) <- It is "considered SV"
= 378000000 *
3.14159 * 0.396 / 648000 = 726 [m/sec]
Notice: Limovie
needs the observer centric distance to calculate the diffraction
effect. However, it is thought the numerical value obtained from
prediction software is a geocentric distance. It can be used as an
approximate value.
For
asteroidal occultation
It
is given by simple equation using the data which is predicted by
Steve Preston.
V[m]=(Diameter[km] / MaxDuration[sec]) * 1000
*
As an example.. (22)Kalliope at Nov.7 in Japan..
SV=181000 / 30.1
= 6103 [m/sec]
Notice: It is an approximate calculation. If
you need more accurate result, especially when the movement of
asteroid is slow, compute in consideration of the rotation of the
earth.
11.Select
[for Occultation / for Grazing] radio button
If
you want to analyze grazing occultation then click [for Grazing]. It
can also be used for analyzing asteroidal occultation.
[for
Grazing] mode is able to calculate the contact angle of lunar limb.
Therefore, we can obtain a information about geographical feature of
lunar limb.
In the case of general lunar occultation, if you only
need time data of event, I recommend to use [for Grazing] mode,
because it is easier than using [for Occultation] mode. Limovie
compute and fit the diffraction curve to the observed data.
[for
Occultation] mode is used for doing measurement more accurately. (in
the case of : Limovie obtained the rate less than 1.0 .. )
12.Click
[Fit to Diffraction Curve] button
For
a while.. The fitness curve is displayed. The yellow line indicate
the centre time of event. And the cross indicate estimated error as
one sigma.
The time is displayed on the Fresnel Diffraction
Analyzing Window as offset time[millisecond] from the centre time of
selected frame.
I
think it is possible to obtain the event time with accuracy 1/100 sec
or less using this method. Of course, without considering the effect
of diffraction, using above procedure from No.1 to No.8, you can
decide the event time more easily than using old version of Limovie.