About calibration settings

Calibration settings are values that are used to achieve calibrated data within an acoustic variable.

Calibration model

Echoview's calibration model takes calibration settings from data, uses default settings where none are available and modifies calibration values using an ECS file. To achieve calibrated data for quantitative analysis, you must verify and correct calibration settings especially when the Message box flags the use of default values or when you know there are incorrect settings recorded with your data. Default values enable Echoview to display echogram data, however the values may be unsuitable for your data. Refer to calibration workflow for more information.

Note: An ECS file may affect multiple EV files or multiple variables. For more information refer to Echoview Calibration Supplement files.

Echoview calibration setting values

Echoview calibration setting names and values are displayed on the Calibration page of the Variable Properties dialog box. Data file values that have been used since the data was loaded or the ECS file was added, saved or removed are displayed in black text. Default values that have been used are displayed in orange text. Data file or ECS values that have been read but not used are displayed in grey text.

Calibration setting values can be changed by using an ECS file, that is added to a fileset through the Calibration section of the Filesets window. Refer to Echoview calibration supplement files for information about the grammar and syntax of ECS files. Echoview can auto-generate an ECS file based on the calculations performed with your data. You can then Copy-Paste calibration setting information to it from the:

Most settings on the calibration pages are used for calculating data point values and data point ranges and must therefore be correctly set for each variable to achieve meaningful displays and analyses. For information on recording calibration settings with exports see Exporting Data.

Settings on the Calibration page of the Variable Properties dialog box are directly associated with the data within the variable. The selection of a transducer and the properties of the transducer used to collect your data should be defined prior to entering calibration settings. See About transducer geometry.

Notes:

  • Echoview initially calculates and displays data using default calibration settings that are not useful for quantitative analyses. Until you change these values, the data values that are displayed in your echograms and used for analyses will be incorrect. Newly modified calibration settings are applied when you recalculate or step through the pings of the echogram.
  • Calibration settings on the Variable Properties dialog box use colored-text cues to indicate the processing that has been done since the data and ECS files were loaded. For more information refer to Calibration page: Settings and Notes.
  • Changes in calibration settings used for range calculations may shift ping data in the depth dimension but will not automatically adjust the position of regions and lines. You should review any existing regions and lines to ensure they are still valid. For more information refer to Range calculation effects on regions and lines.
  • Calibration settings for analysis exports are specific to each variable, and are not included in export data.
  • Data management tips:
    • To ensure that you have a permanent record of the calibration settings for your export, create a read-only folder to store your export data.
    • For each export, save a copy of the EV file to the folder path of the export. If you used an ECS file, save a copy of the ECS file as well.

A summary of how the calibration settings are used for the variables in each data set is available on the following pages:

Additional uses of calibration settings

Some calibration settings are used for purposes other than calculating the data point values or ranges.

Calculations affected by specific calibration settings are:

The tables below describe which calibration settings affect these calculations. If you intend using TVG, background noise analysis variables, corrected schools analysis variables, beam volume sum or single targets the calibration settings listed must be entered correctly for the specified variables.

Note: The tables apply to both raw and virtual variables from data logged with any echosounder.

Sv variables

Setting

Affects

Calibration page of Variable Properties dialog box

AbsorptionCoefficient

Background noise analysis variables.
Time-varied thresholds.

TwoWayBeamAngle

Beam volume sum

PulseDuration

Corrected schools analysis variables.

Sample thickness.

SoundSpeed

Sample thickness.

SimradDraftLogging (where available)

Corrected schools analysis variables.

Frequency

Frequency Response graph.

MajorAxis3dBBeamAngle

MinorAxis3dBBeamAngle

Multibeam bottom detections export (Athwartship).

WedgeVolumeBeamAngle

Wedge volume sampled algorithm (when you want to override the Major-axis 3 dB beam angle).

MinorAxis3dBBeamAngle

Corrected schools analysis variables.

TS variables

Setting

Affects

Calibration page of Variable Properties dialog box

AbsorptionCoefficient

Time-varied thresholds

SoundSpeed

Sample thickness.

PulseDuration

Virtual variables created by single target detection operators using the PLDL and normalized pulse length.

Single target and target length variables

Setting

Affects

Calibration page of Variable Properties dialog box

CalibrationOffsetTs

Calibration Assistant, Output Generic, Narrowband.

See also the Calibration Assistant note below.

FrequencyTableWideband

MajorAxisAngleOffsetTableWideband

MajorAxisBeamWidthTableWideband

MinorAxisAngleOffsetTableWideband

MinorAxisBeamWidthTableWideband

TSOffsetTableWideband

Calibration Assistant, Output Generic, Wideband

FrequencyTableWideband

GainTableWideband

MajorAxisAngleOffsetTableWideband

MajorAxisBeamWidthTableWideband

MinorAxisAngleOffsetTableWideband

MinorAxisBeamWidthTableWideband

Calibration Assistant, Output Simrad Specific, Wideband

PulseDuration

Single target display thickness1

Virtual variables created by single target detection operators using the PLDL and normalized pulse length.

Sample thickness.

SoundSpeed

Single target display thickness1

Sample thickness.

Calibration Assistant, Output Simrad Specific, Narrowband/Wideband

Calibration Assistant, Output Generic, Narrowband/Wideband

SamplingFrequency

Sample thickness.

TwoWayBeamAngle

Beam volume sum2

 

MajorAxis3dBBeamAngle

MinorAxis3dBBeamAngle

Beam compensation of single targets detected in Echoview.
3D Single targets graph beam rings.

Calibration Assistant, Output Simrad Specific, Narrowband

Calibration Assistant, Output Generic, Narrowband

MajorAxisAngleOffset

MinorAxisAngleOffset

TwoWayBeamAngle

Calibration Assistant, Output Simrad Specific, Narrowband

Calibration Assistant, Output Generic, Narrowband

TransducerGain

SaCorrectionFactor

 

Calibration Assistant, Output Simrad Specific, Narrowband

Notes:

  • 'Single target' refers to single target data from single target detection variables. The calibration settings for raw single target variables can be different to single target detection variables.
  • 1 Except for virtual variables in the Single target manipulation operators group. The Single target display thickness for these virtual variables is inherited from the first operand.
  • 2 Except for Target length variables, where the calculation of Beam volume sum is not supported.
  • The Calibration Assistant is launched from a selection or region on a single target detection variable and considers the calibration values of the contributing operands when calculating calibrated settings.

Deprecated calibration names

Echoview supports multiple names for a calibration setting name. Deprecated names used in existing EV files and scripts and current calibration names for the same setting are handled seamlessly.

Affected names include:

Note: The single target data export outputs Pulse_duration in place of Transmitted_pulse_length.

See also

About calibrated data
Calibrating an echosounder
Calibration settings for virtual variables
About time varied gain