specification.readme

超声仿真软件

 Specification of the beamforming toolbox. The beamforming toolbox can 
beamform one line or one image at a time.  The way it operates depends
on the user.


Commands :
-------------------------------------------------------------------------   
BFT_INIT - Initialize the beamforming toolbox. Set some of the constants
   SYNTAX  : bft_init
   INPUT   : None
   OUTPUT  : None
   
   
-------------------------------------------------------------------------   
BFT_END - End working with the toolbox. Release all the allocated memory.
   SYNAT   : bft_end
   INPUT   : None
   OUTPUT  : None
   
   
   
-------------------------------------------------------------------------   
BFT_PARAM - Set a parameter, necessary for the beamforming. 
   SYNTAX  : bft_param('param_name', param_value)
   INPUT   : 'param_name' - String with the name of the parameter. 
                            Currently recognized are :
                            'c'  - Speed of sound         [ m / s]
                            'fs' - Sampling frequency     [  Hz  ]
   OUTPUT  : None




-------------------------------------------------------------------------   
BFT_NO_LINES - Number of lines beamformed at teh same time by calling
       the command "bft_beamform". Calling this command makes all previous 
       definitions of delays and focus points disappear.
   SYNTAX  : bft_no_lines(no_lines)
   INPUT   : no_lines  - Number of lines to define. The default value 
                         is 1 (when this command is not invoked)
   OUTPUT  : None



-------------------------------------------------------------------------
BFT_TRANSDUCER - Set the transducer. This command is necessary to call 
       in order to set the transducer coordinates. They are used later in
       the calculations of the delays.
   SYNTAX  : xdc = bft_transducer(element_centers)
   INPUT   : element_centers - a matrix of the form [x[1], y[2],  z[1];
                                                     x[2], y[2],  z[2];
                                                           . . .
                                                     x[n], y[n],  z[n]]
                               The coordinates [x,y,z] are given in meters.
   OUNPUT  : xdc - handle to a transducer definition




/************************************************************************
 *   FUNCTIONS OPERATING ONLY ON ONE LINE AT A TIME. IN THIS CASE THE 
 *   USER MUST DEFINE  A LOOP IN MATLAB AND BEAMFORM A SINGLE LINE PER
 *   ITERATION. THESE ARE USEFUL WHEN THE DEMAND FOR MEMORY IS TOO BIG
 *   OR WHEN THE USER USES THE SAME SYNTAX AS IN Field II.
 ************************************************************************/
-------------------------------------------------------------------------
BFT_CENTER_FOCUS - Set the center focus for the focusing. This point is 
      used as reference for calculating the focusing delay and times, and
      as a starting point for the dynamic focusing.
   SYNTAX  : bft_center_focus(xdc, point)
   INPUT   : xdc - Handle of the aperture associated with the focusing
             point - Focus center point (x,y,z)
   OUTPUT  : None
   
   
   
   
-------------------------------------------------------------------------   
BFT_FOCUS  - Set the focus time line (for the definition of time-line 
       look in the documentation of FieldII) for a given line in the 
       image. The command must be used when there is only one line in 
       the image. 
   SYNTAX  : bft_focus(xdc, times, points)
   INPUT   : xdc   - Handle of the transducer definition
             times - Time after which the associated focus is valid
             points- Focus points. Vector with three columns (x,y,z) and
                     one row for each field point
   OUTPUT  : None
   



-------------------------------------------------------------------------   
BFT_FOCUS_TIMES - Set the delays for the beamforming. 
      The command must be used when only one is defined.
   SYNTAX  : bft_focus_times(xdc, times, delays, );
   INPUT   : xdc - Handle of a transducer definition.
             times - Time after which the associated focus is valid.
             delays - Matrix with the delays - one column per element, 
                      one row per field time.
   OUTPUT  : None




-------------------------------------------------------------------------   
BFT_DYNAMIC_FOCUS - Use dynamic focusing.
   SYNTAX  - bft_dynamic_focus(xdc, time, dir_zx, dir_zy)
   INPUT   - xdc - Handle to the transducer definition.
             time - Time after the dynamic focus is valid
             dir_zx - Direction (andle) in radians for the dynamic focus
                     The direction is taken from the center for the focus
                     of the transducer in the z-x plane.
             dir_zy - Direction (andle) in radians for the dynamic focus
                     The direction is taken from the center for the focus
                     of the transducer in the z-y plane.
   OUTPUT  - None
   



/************************************************************************
 * FUNCTIONS FOR BEAMFORMING A WHOLE IMAGE. THE USER MUST FIRST DEFINE 
 * THE IMAGE AND THEN START CALLING THE BEAMFORMING ROUTINE IN ORDER TO 
 * GAIN SPEED. USEFUL WHEN MAKING MOVIES OR PROCESSING HUGE AMOUNTS OF
 * DATA.
 *
 ************************************************************************/

-------------------------------------------------------------------------
BFT_TIMES Set the times after which the next focusing zone for all the lines
      is valid. This command must be called prior to calling the other 
      routines for setting the focusing and the times.
   SYNTAX  : bft_times(xdc, times)
   INPUT   : xdc - Handle to trasnducer definition
             times - Time after which the next focus is valid. 
   OUTPUT  : None
   
   
   
-------------------------------------------------------------------------
BFT_CENTER_FOCUSLN - Set the center focus for the focusing for. This point is 
      used as reference for calculating the focusing delay and times, and
      as a starting point for the dynamic focusing.
   SYNTAX  : bft_center_focusln(xdc, point, line_no)
   INPUT   : xdc - Handle of the aperture associated with the focusing
             point - Focus center point (x,y,z)
             line_no - Number of line for which we set the center.
   OUTPUT  : None
   
   
   
   
-------------------------------------------------------------------------   
BFT_FOCUSLN - Set the focus time line (for the definition of time-line 
       look in the documentation of FieldII) for a given line in the 
       image. The command must be used when there is only one line in 
       the image. 
   SYNTAX  : bft_focusln(xdc, times, points, line_no)
   INPUT   : xdc   - Handle of the transducer definition
             points- Focus points. Vector with three columns (x,y,z) and
                     one row for each field point. The number of points 
                     must be equal to the number of times set by 
                     BFT_TIMES
             line_no - Number of line.
   OUTPUT  : None
   



-------------------------------------------------------------------------   
BFT_FOCUS_TIMESLN - Set the delays for the beamforming. 
      The command must be used when only one is defined.
   SYNTAX  : bft_focus_timesln(xdc, delays, line_no);
   INPUT   : xdc - Handle of a transducer definition.
             delays - Matrix with the delays - one column per element, 
                      one row per field time. The number of rows is 
                      equal to the number of times set by the BFT_TIMES
             line_no - Number of line.
   OUTPUT  : None




-------------------------------------------------------------------------   
BFT_DYNAMIC_FOCUSLN - Use dynamic focusing.
   SYNTAX  - bft_dynamic_focus(xdc, time, dir_zx, dir_zy, line_no)
   INPUT   - xdc - Handle to the transducer definition.
             time - Time after the dynamic focus is valid
             dir_zx - Direction (andle) in radians for the dynamic focus
                     The direction is taken from the center for the focus
                     of the transducer in the z-x plane.
             dir_zy - Direction (andle) in radians for the dynamic focus
                     The direction is taken from the center for the focus
                     of the transducer in the z-y plane.
             line_no - Number of line
   OUTPUT  - None
   
   

   
   
-------------------------------------------------------------------------   
BFT_BEAMFORM Beamforms the image using the definitions associated with 
      given aperture.
   SYNTAX  : [bf_lines] = bft_beamform(xdc, start_time, rf_data)
   INPUT   : xdc - Aperture defining the delays and the image and etc.
             start_time - The acquisition time of the first sample.
             rf_data    - The recorded RF lines.
   OUTPUT  : bf_lines - Beamformed RF lines. The number of RF lines 
                        corresponds to the number of lines defined by 
                        the command BFT_NO_LINES.



-------------------------------------------------------------------------   
BFT_BEAMFORMLN Beamforms one line using the definitions associated with 
      given aperture. 
   SYNTAX  : [bf_line] = bft_beamformln(xdc, start_time, rf_lines, line_no)
   INPUT   : xdc - Aperture defining the delays and the image and etc.
             start_time - The acquisition time of the first sample.
             rf_lines   - The recorded RF lines.
             line_no    - Number of line to beamform.
   OUTPUT  : bf_line - Beamformed RF line.