View_AB
VIEW_AB.EXE allows
to display and analyse the contents of rawdata files (V*.AB).
All Operations
like opening files, certain display modes etc. could be done right within the
program.
VIEW_AB.EXE will
quit when <ESC> is pressed. Alternatevely the program quits when clicking
the “Close”-option within the File-Menu.
The Menu-Option
“Rawdat Parameter” controls the behaviour of the program.
There you can
start and stop displaying raw-data and you can also choose the
appropriate kind of view.
Display
and analysis of raw data
1. Asynchronous display
The asynchronous
raw data display is called by starting RAWDAT with the Menu-Option “Asynchrone
view” (could be found in Rawdat Parameter). The two data streams of the two
cameras are visualized in the left and the right half of the
screen (upper system =
cam A = front view = left half of screen, lower system = cam B = side view =
right half). The two displays are not synchronized.
The x-axes
represent the 512 pixel of each of the cameras. The y-axis represents a time scale, one line corresponds to around 29 microseconds (at a
line scan frequency of approx. 34.5 kHz). The full height of the picture
corresponds to around 1800 lines, i.e. approx. 52 milliseconds. Periods with no
data are omitted in the display, a horizontal line
indicates such a time jump.
After having
detected shadowed areas within one line it is the next task of data
preprocessing to identify valid
elements in each of the cameras data streams. The result of this procedure is
visualized in this display. Elements recognized as valid are shown in red resp.
blue colour. Invalid elements are shown in grey colour.
Fig. 1 Asynchronous View
2. Synchronous display
The synchronous
raw data display is called by invoking RAWDAT with with the Menu-Option
“Synchrone view” (could be found in Rawdat Parameters).
The two data
streams of the two cameras are visualized in the left and the right half of the
screen (upper system = cam A = front view = left half, lower system = cam B =
side view = right half). The two displays are synchronized. The x-axes
represent the 512 pixel of each of the cameras. The y-axis represents a time scale, one line corresponds to around 29 microseconds (at a
line scan frequency of approx. 34.5 kHz). Periods with no data are omitted in
the display, a horizontal line indicates such a time
jump.
Elements discarded
as invalid in the first preprocessing step are not displayed here.
As the next task
elements of the two cameras have to be linked to pairs. If such a pair is
considered to be a valid one, it is displayed in red and blue colour. In case
of an invalid pair (e.g. big front view element, small side view element) the
colour is grey. Particles outside the intersecting measuring area are seen in
only one camera, they are displayed in grey color.
Valid pairs found
in here go into the hydrometeor data file (V*.HYD) which may be displayed by
OFFL.
Fig. 2
Synchronous View
3.
Access to the raw data
The user may
access the raw data files. A full sample how to decompress the file format is
given in the subdirectory TYPE_AB. TYPE_AB has been prepared to be compiled by
the Microsoft Visual C++-compiler (Version 6.0 and higher).