About algorithms

This reference section provides details of algorithms and equations used in Echoview. Our objective is to provide enough detail that you can replicate, outside Echoview, the calculation of any quantity that can be exported from Echoview. Other algorithms such as line picking algorithms and inclusion algorithms (for example, is a sample inside a given region?) are described so that you can understand how Echoview works and thus how your data are processed.

Terminology used in Echoview and Echoview Help follows the definitions, units and symbols recommended in MacLennan, D.N. and Fernandes P. (2000): Appendix D - Definitions, Units and Symbols in Fisheries Acoustics. Report of the Working Group on Fisheries Acoustics Science and Technology, Ijmuiden/Haarlem, Netherlands 10-14 2000. This report can be downloaded from Report of the Working Group on Fisheries Acoustics Science and Technology, Ijmuiden/Haarlem, Netherlands 10-14 2000

• 2D school detection - SHAPES variables
• 3D school detection
• Analysis domain
• Analysis variable algorithms
• Background noise analysis variables
• Beam compensation models
• Bottom classification
• Calibration Assistant
• Calibration sphere modeling and references
• Calculation for new complex magnitude
• Echosounder calculations for instrument file formats
• Echosounder calculations (other) including TVG algorithms
• Fish tracking
• GPS fix status
• Integration line
• Integration variables
• Line pick
• Mapping and projections
• Minimum TS threshold
• Multibeam bottom detection
  
• Off-axis angle
• Water current speed distance equation
• Operators

Arithmetic

Code Constant divide Constant multiply Current velocity magnitude Formula Linear minus

Linear plus Maximum Mean of 3 Minus Minimum

Plus Variance of 3

Data manipulation

Attenuated signal removal Background noise estimation Background noise removal Calibration subset Cell statistic Cell statistic - Single targets Copy Data generator Deadzone estimation Extract bottom feature Extract transmission characteristic

FIR filter IIR filter Impulse noise removal Join opposing pings Live export Match geometry Match ping times Maximum intensity - Matrix Merge GPS Merge pings Motion correction (Dunford method) Ping subset

Ping time shift Processed Data Reduce pings Reduce pings (method 2) Region statistic Resample by distance interval Resample by number of pings Resample by time interval Sector select Signal to background noise ratio Threshold

Towed body Transect subset Transient noise ping removal Transient noise sample removal Wideband frequency select Wideband frequency subset

Bitmap operators

And Line bitmap Mask Not

Or Data range bitmap Line range bitmap Motion range bitmap Region bitmap

Select Target bitmap Target samples bitmap Trained model bitmap (experimental)

Conversion

dB to linear Type conversion Linear to dB

Sv to TS TS to Sv Current velocity component to linear conversion

Convolution

3x3 convolution 5x5 convolution 7x7 convolution

XxY convolution XxY statistic XxYxZ convolution XxYxZ statistic

Blur Dilation filternxn Erosion filternxn

Sharpen

Imaging

3 color maximum GLCM Energy GLCM Entropy GLCM Contrast

GLCM Homogeneity GLCM Correlation GLCM Shade GLCM Prominence Monochrome

Overlay To Color

Line

Arithmetic Best bottom candidate line pick Crop

Fixed depth Linear offset Maximum Sv line pick Near-field depth estimation

Off-axis angle offset Smoothing filter Span gaps

Statistical combination Threshold offset Time offset Towed body time offset Trained model bottom exclusion (experimental)

Movement

Distance correction GPS filter

Kalman GPS smoothing filter Ping time difference

Vessel speed at pings

Multibeam

Angle select Beam select Beam closing filter 3x3 Beam convolution 3x3 Beam dilation filter 3x3 Beam erosion filter 3x3

Beam median filter 3x3 Beam opening filter 3x3 Beam scan Beam subset Bottom Echo Bitmap Bottom Echo Bitmap H-mode - Furuno Combine Fans

Double threshold Kovesi image denoising Maximum Intensity Mean of n previous pings Median of N pings Minimum of N pings

Multibeam background removal Multibeam roll at transducer Multibeam target detection and Target linking Multibeam target overlay Multibeam target samples bitmap Resample multibeam pings Sample statistic subtract Target conversion XxYxZ convolution XxYxZ statistic

Single target detection

Single target detection - single beam (method 1) Single target detection - single beam (method 2) Single target detection - split beam (method 1) Single target detection - split beam (method 2) Single target detection - dual beam (method 1) Single target detection - dual beam (method 2) Single target detection - wideband Single target detection - Furuno FCV-30

Beam compensation

Single target manipulation

Target length calculator Target length conversion Target property threshold

TS substitution ST difference ST intersection

ST union

Surface

Fixed Depth Fixed Range Linear Offset

• Ping position status
• Processing GPS
• Region gridding
• Region tracking
• Sonar calculator
• Time-varied threshold

Please contact Echoview support if an algorithm or equation that you require is not described or if you require further information.