L. Haikin, M. Rozhkov, A. Petrov
INTELLIGENT AUTOMATIC SYSTEM FOR DIGITIZING OF SEISMOGRAMS
Software Manual Version 1.2.2 January 30, 1995 Prepared by SYNAPSE SCIENCE CENTER
Moscow Data Center " SYNAPSE" Ostozhenka street 9 Moscow 107065
***  OLD VERSION  *** (without figures)
        C O N T E N T:
1. DESTINATION

2. ABSTRACT

3. DESCRIPTION OF WINDOWS
                3.1. MAIN WINDOW
                3.2. SAVE LINE WINDOW
                3.3. CLEAR VERT WINDOW
                3.4. ROTATE WINDOW
                3.5. ARC WINDOW

1. DESTINATION
INTELLIGENT AUTOMATIC SYSTEM FOR DIGITIZING OF SEISMOGRAMS (IDS) is intended to digitize the photo and paper seismograms and convert these data into standard WF-disc files of CSS 2.8 format. Photo and paper seismograms are to be scanned previously into PCX-format files. Source information: PCX-file of multi-channels seismogram. Results: Corresponding WF-disc files in current directory. System Soft environment: Computer SUN/4, OS-4.1

2. ABSTRACT

Multi-channels seismogram PCX-file is loaded into the memory and imaged onto the canvas. This image is viewed by User. The User performs the time tieing of the image to epoch time and sets the time scale. Then he sequentially selects, digitizes and puts out every channel as a file. All User's commands and interaction take place directly within the graphical display windows. Control buttons appear at the top of the window. The effects of mouse pointer and button events in the display windows depend on where the mouse is currently located. To perform a time scale tieing, the visible seismogram's time marks are used. The selection of one channel trace is performed on the base of User's drawn horizontal axis and automatic segment cluster analysis method [M.Rozhkov, A.Petrov]. The segment is an uninterrupted domain of black pixels onto the screen. The digitizing is based upon the spline approximation method. During the digitizing The User is able to correct graphically the list of selected segments in order to achieve a maximum of coincidence of digitizing line with channel trace. Every User's approached step may be displayed onto the screen, thus the whole process is performed recursively. The last stage of digitizing is the handle editing of line by means a mouse. The conversion of data to CSS format demands the resampling and scaling of the digitized pixels coordinates values array in concordance of real data acquisition system, from which the data were received. This conversion is controlled by User by means the setting up of new sampling rate and scale coefficient. During the resampling the new amplitude values are estimated by means of linear interpolation of two nearest pixel's values. The quality of resampling may be checked visually by drawing of new curve along the old trace. The output data representation (double precision, float, integer 4, integer 2 or arbitrary ASCII format) may be selected by the User. The formed output data are placed into the two files. Header of data array is placed into the WF-disc file in current directory. Header is a standard WF-disc record, that includes a Julian date, time of trace, name of station, channel code and others characters of channel. Besides it contains a directory name for wave form file, which is assigned as a sub directory of current one. If time is the same as in a present record, the new record will replace old one in WF-disc file and new trace will do so, else a new WF-disc file will be formed. During selection the User is able to perform some added operations over the traces such as a rotate of image, transforming of arcous image to rectangular one and clearance the vertical scale lines.

3. DESCRIPTION OF WINDOWS

The goal is achived in interactive regime, supported by five pop-up windows (fig.1).
3.1. MAIN WINDOWS
Main window (SCANNED SIGNAL DIGITIZING) is used for reading of file, time tieing of image, selection and digitizing of trace.
Save data window is used for forming of results WF-disc files.
Rotate image window is used to rotate the seismogram, if scanning was not done correctly and trend in direction will disturb to achieve a good results.
Arc window (Transforming to rectangular coordinates) is used for conversion of arceous image to rectangular one, so the only admissible source form to digitize is a rectangular image.
Clear verticals window (Clear vertical scale lines) is used for clearance of vertical scale lines, those cause the falacious deviation from true curve direction during the automatic segments selection.

3.1 MAIN WINDOW

Main window contains the canvas for seismogram image and panel with some panel's tools. The Main Window control buttons are as follows:

Quit             Causes the termination of the job.
Help             Causes help information to be displayed.
Clear vert   Creates a new display Window for Clearance of vertical scale lines.
Rotate         Creates a new display Window for rotate of image.
Arc              Creates a new display Window for Convertion of the arceous image to rectangular one.
Save line     Creates a new display Window for resampling of data array and forming of output WF-disc files.

Then the Main Window pannel contains some Command strings for typing of users data and appropriate pull-down buttons. This strings are as follows:
Source file     Is the area for typing PCX file name.
Load               Causes the loading of mentioned file.
Human time   Is the area for typing of epoch time in accordance of the drawned line.
Apply              Causes the tiped Human time to set.
Seconds between time marks -     is the area for typing of amount of seconds between last two time marks during the tyeing.
Apply            Causes the tiped interval to set.

Besides the Main Window pannel contains Choice button Scale for icreasing of image by 2,4 or 8 times. At last the Main Window pannel contains pull-down menu for setting of Mode as follows:

3.2 SAVE LINE WINDOW
Save line Window is intended to set the some parameters for output data. The Window control buttons are as follows.
3.3. CLEAR VERT WINDOW
Clear verticals window (Clear vertical scale lines) is intended to erase the vertical scale lines, those cause the falacious deviation from true curve direction during the automatic segments selection. This tool is important, when the steady bold vertical scale lines take place onto the image. The Window control buttons are as follows. Then Window pannel contains pull-down menu for setting of Mode as follows:
3.4. ROTATE WINDOW
Rotate window is intended to rotate the seismogram, if scanning was not done correctly and steady trend in direction will disturb to achieve a good results. The Window control buttons are as follows. Then the Rotate Window pannel contains pull-down menu for setting of Mode as follows:
3.5. ARC WINDOW
Arc window (Transforming to rectangular coordinates) is intended to convert the arceous image into rectangular one, so the only admissible source form to digitize is a rectangular image. The Window control buttons are as follows. Then the Arc Window pannel contains pull-down menu for setting of Mode as follows:
4. PROGRAM INTERACTION
4.1. DIGITIZING
After starting of job (dgs & ) the main window is appeared (fig.1). First of all it is needed to type the PCX file name and push the button "Load". The loading is a comparatively long ti- me process (10-30 s) and it should be wait until the whole cop- letion. The order of next actions of User may be arbitrary: time scale tieing, human time setting, digitising. The only demand is : Before saving of line, all three actions mentioned above, are to be performed and before digitising the two boundaries are to be set. Despite this, to provide a minimum efforts, we recommend, in general, the next order of user's actions: At the beginning of job: human time setting of seismogram and time scale tieing of image. Then for every interested trace:
- select axe;
- select and unselect segments;
- set two boundaries;
- digitising, repeated selection and anselection of segments and recoursive repeated digitising;
- manual edit the trace;

- show the save line window;
- set the output representation (only for first trace) ;
- set the Station and channel code;
- set the sampling rate (only for first trace) ;
- set the scale coefficient (only for first trace) ;
- set the comment;
- create wfdisc and waveform files.
If the quality of scanned image is dood enough, the recou sive segment selection is not necessary and well digitising line will be formed at once.

4.2. SETTING OF VARIABLE TIME SCALE
In order to provide a maximal precision of tieing, the lines must be drawn through the well visible marks only. The number of time marks would like to be as much as possible. The time marking may begin from arbitrary mark of diagram sequentially in both direction. Poor visible marks may be skipped. After drawing of the first two lines it is necessary to enter the amount of seconds between these two lines and continue marking. Every interval between next two marks (in seconds) is defined automatically on the basis of previous step. If during this automatic definition the deviation from integer second will exceed the permitted value (for example 0.1) , the user is prompted to precise the number of seconds in interval. Then the automatic process will be continued. If during the process the User has decided to go back to to the one of the previous point, He should take into account, that all lines set already futhermore will be deleted. To check the tieing process by the User, every time after drawing of the next line, the table of variabe time scale of ima- ge is displayed onto console.
4.3  CLEARANCE OF THE VERTICAL SCALE LINES
Clearance of the vertical scale lines is intended to erase the vertical scale lines, those cause the falacious deviation from true curve direction during the automatic segments selection. This tool is important, when the steady bold vertical scale lines take place onto the image. To achieve this goal it is needed to define the line, that may be considered as a strict vertical (fig.2,3). This line is defined by the two points in the upper and downer parts of the image. For more convenience it is provided a number of intermediate points, while the line is drawn throughout the two extreme points only. The points are placed in the mode "Set points". If new point is positioned near the old one, it replaces old point on the screen. When pressing the "Draw axis" button, the vertical line is drawned. The drawned line may be deleted for more precise line (if desirable) in "Delete axes" mode. The vertical lines may be erased or replaced by the left neighboring pixels columns (the transforming of the image is performed from the left side to write). The method is slected by the "Method to replace line" choice button. After setting of method it is needed to define the Saturation - a percentage black pixels in column, that is a criterion to concider this column as a vertical scale line, to be deleted. At last it is needed to press onto the "Apply" button and wait the new image, to be futher digitized.
4.4. ROTATION OF IMAGE
Rotation of seismogram is used, when the scanning was not done correctly and steady trend in direction will disturb to achieve a good results. To rotate the image it is needed at first to draw the axis in main screen, so that the line must overlay the medium point of trace onto the left side of image. Then it is needed to push the "Rotate" button and after appearance of new window - select right point of real trace axis (fig. 4). The drawned new axis may be moved by placing of new point near axis or deleted in "Delete new axis" mode. If the clearance of vertical lines is desirable, the parameters of this procedures must be defined as in the special Clear verticals window.(see 4.3.) Then the User will have to push the "Apply" button and wait the new image, to be futher digitized (fig.5).
4.5. TRANSFORMING TO RECTANGULAR COORDINATES
This function is used for conversion of the arceous image to rectangular one, so the only admissible source form to digitize is a rectangular image. To transform the image it is needed to push the "Arc" button in main window just after the loading of arceous PCX-file. So the new appropriate window will emerge. Then we have to set the "Sel axes" mode and draw all axes. The control number of axes will be written in relevant string of the window. The order of axes may be arbitrary. Besides we are able to precise a location of axis by pressing the left mouse button near the old axis. In "Del axes" mode these actions will cause the mentioned axes to be deleted. The axis definition is needed for futher estimation of pen shoulder radius and transorming of arceous coordinates. If we know exactly the apparatus size of pen radius we should merely to input this value (in pixels) in "Average radius" command string and push the "Apply", and we should take into acount the real characters of our SUN computer monitor. If we don't know the apparatus size of pen radius we should to perform some graphic measuring on the screen. To define a radius we should take two points on the good visible arc: one on the axis (on diameter) and one far from axis. The program estimates a radius size and writes a value onto the screen. In order to exclude the random factor we should repeat this experience several times and confirm the average by pressing onto the nearest "Apply" button. The number of experience is shown in the string, named as "Number of test". If we don't satisfy about the results, we may cancel the radius by pressing the button, named as "Cancel radius" and repeat measure once again. If all is O.K. we should push the upper "Apply" button to start the transforming procedure. Futher User's interaction is the same, as with ordinary rectangular seismogram (fig.7). The downer part of Arc window is also intended for clearance of vertical scale lines.