OpticalFlow

OpticalFlow estimates the 2-D velocity of a field using optical flow tracking.

Overview

OpticalFlow estimates the 2-D velocity of a field in an MDV file by performing optical flow tracking. The optical flow code was provided by Alan Seed of the Australian Bureau or Meteorology.

Prerequesites

The following items are required:

• MDV radar files

Parameter file

OpticalFlow uses one parameter file that includes the input/output directories and optical flow algorithm parameters.

Ensure file is up to date

To obtain the default parameter file, use the following command:

/path/to/lrose/install/bin/OpticalFlow -print_params > param_file_name

If you already have a parameter file and simply want to check for (and add) updated parameters while retaining current parameters, use the following command:

/path/to/lrose/install/bin/OpticalFlow -params orig_param_file_name -print_params > new_param_file_name

Important parameters

Debug and process control

• mode: determines if the program waits for new files (REALTIME), moves through start and end times specified on the command line (ARCHIVE), or moves through list of files specified on the command line (FILELIST)

Data input

• input_url: path of the input data
• set_vlevel_limits: option to set limit on vertical levels included in the composite
• tracking_field_name: name of the field to be tracked

Data output

• output_url: path where the output files are written to
• write_composite_field_to_output: option to write the composite field used in the calculation to the output field

Running OpticalFlow

To check all command line options for OpticalFlow, including debugging options and file paths, type the following command into a terminal.

/path/to/lrose/install/bin/OpticalFlow -h

Once your parameter file is complete, use a command similar to the following to run the application:

/path/to/lrose/install/bin/OpticalFlow -params param_file_name

The user can also specify the location of cfradial files in the following manner:

/path/to/lrose/install/bin/OpticalFlow -f /path/to/cfradial/files/ -params param_file_name