7k_reflectivity_check

Description

7k_reflectivity_check is a utility designed to extract and compare reflectivity (intensity) data from different Reson 7k data records. It reads a Reson 7k (.s7k) file, processes 7k_7000_Sonar_Settings, 7k_7006_Bathymetry, 7k_7007_Backscatter, and 7k_7008_Generic_Data (snippets) records, and then outputs selected intensity values for each beam.

The primary purpose of this tool is for quality control and detailed analysis of backscatter data, allowing users to assess the consistency of intensity measurements from different sources within the 7k data stream.

Usage 

7k_reflectivity_check -s7k <input_name> [-v] [-debug]

Arguments

Option Description  
-s7k <input_name> Required. Path to the input Reson 7k .s7k file.  
-v Enable verbose output (prints DRF information).  
-debug Enable debug output (currently unused).  

How It Works

  1. Initialization: Parses command-line arguments, sets the input .s7k filename, and initializes Reson 7k data structures (Reson_7K_DRF, Reson_7K_7000_Sonar_Settings, Reson_7K_7006_Bathymetry, Reson_7K_7007_Backscatter, Reson_7K_7008_Generic_Data).
  2. File Opening: Opens the input .s7k file for reading and creates four output ASCII files: intensity.dat, snippet.dat, snippet_max.dat, and snippet_min.dat.
  3. Record Processing Loop: Reads the .s7k file record by record:
    • Sync Search: Calls seek_next_7K_sync() to find the next Reson 7k synchronization pattern.
    • DRF Reading: Reads the Reson_7K_DRF (Data Record Format) to determine the record type and size.
    • Record Parsing: Uses a switch statement to call the appropriate read_Reson_7K_*() function (read_Reson_7K_7000_Sonar_Settings, read_Reson_7K_7006_Bathymetry, read_Reson_7K_7007_Backscatter, read_Reson_7K_7008_Generic_Data) based on the record_type_id.
    • Ping Matching and Corruption Check: It skips records if the ping_number does not match across all relevant record types (Sonar Settings, Bathymetry, Backscatter, Snippets) or if any record is marked as corrupt.
    • Data Extraction and Output: If a consistent set of records for a ping is found:
      • For each beam in the bathymetry record:
        • Writes bathymetry.beams[beam].intensity to intensity.dat.
        • Writes snippets.records[beam].magnitude_16[74] (a fixed sample index) to snippet.dat.
        • Finds the max and min amplitude within the first 150 samples of the snippet record and writes them to snippet_max.dat and snippet_min.dat, respectively.
  4. Cleanup: Closes all open files.

Output Files

  • intensity.dat: ASCII file containing bathymetry-derived intensity values for each beam.
  • snippet.dat: ASCII file containing a specific snippet sample (sample 74) for each beam.
  • snippet_max.dat: ASCII file containing the maximum snippet amplitude for each beam.
  • snippet_min.dat: ASCII file containing the minimum snippet amplitude for each beam.

Dependencies

  • Reson_7K_parser.h: For Reson 7k data structures and parsing functions.
  • support.h: For general utility functions and error handling.

Notes

This tool is invaluable for quality control and detailed analysis of backscatter data from Reson 7k systems. It helps in assessing the consistency of intensity measurements between different data sources within the 7k stream, which is crucial for accurate seafloor characterization. The output ASCII files can be used for plotting and further statistical analysis.