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

Arithmetic operators

Constant divide
Constant multiply
Current velocity magnitude
Linear minus

Linear plus
Mean of 3
Variance of 3

Data manipulation operators

Attenuated signal removal
Background noise estimation
Background noise removal
Calibration subset
Cell statistic
Cell statistic [Single targets]
Data generator
Deadzone estimation

FIR filter
IIR filter
Impulse noise removal
Join opposing pings
Live export
Match geometry
Match ping times
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

Signal to background noise ratio
Towed body
Transect subset
Transient noise ping removal
Transient noise sample removal
Wideband frequency select
Wideband frequency subset

Bitmap operators

Line bitmap

Data range bitmap
Line range bitmap
Motion range bitmap
Region bitmap

Target bitmap
Target samples bitmap
Trained model bitmap (experimental)

Conversion operators

dB to linear
Type conversion
Linear to dB

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

Convolution operators

3x3 convolution
5x5 convolution
7x7 convolution

XxY convolution
XxY statistic
XxYxZ convolution
XxYxZ statistic

Dilation filternxn

Erosion filternxn

Imaging operators

3 color maximum
GLCM Energy
GLCM Entropy
GLCM Contrast

GLCM Homogeneity
GLCM Correlation
GLCM Shade
GLCM Prominence

To Color

Line operators

Best bottom candidate line pick

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 operators

Distance correction
GPS filter

Kalman GPS smoothing filter
Ping time difference
Scan position
Vessel speed at pings

Multibeam operators

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
Resample multibeam pings
Sample statistic subtract
Target conversion
XxYxZ convolution
XxYxZ statistic

Single target detection operators

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 operators

Target length calculator
Target length conversion
Target property threshold

TS substitution
ST difference
ST intersection
ST union

Surface operators

Fixed Depth
Fixed Range
Linear Offset


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