Operators

In Echoview, an operator is an algorithm which acts upon an operand to produce a virtual variable. The operators implemented in Echoview have been chosen for their generality to allow maximum flexibility in visualizing and analyzing data. All operators are licensed with the Advanced Operators module, except those indicated in Operator licensing in Echoview.

Notes:

Echoview operators are grouped for convenience, as follows:

Arithmetic operators
Data manipulation operators
Bitmap operators
Conversion operators
Convolution operators
Imaging operators
Line operators
Surface operators
Movement operators
Multibeam operators
Single target detection operators
Single target manipulation operators

Arithmetic operators

Operator

Description

Code

Code

Constant divide

Constant Divide

Constant multiply

Constant Multiply

Current velocity magnitude

This operator returns the magnitude of the current velocity given three orthogonal current velocity component variables. The resultant acoustic virtual variable has a linear data type.

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

Operand 3

  • Current velocity component

  • Current velocity component

  • Current velocity component

Formula

Formula

Linear minus

This operator subtracts two variables in the linear domain. Operand 2 is subtracted from operand 1.

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Sv
  • TS
  • Unspecified dB
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Sv
  • TS
  • Unspecified dB

Linear plus

This operator adds two variables in the linear domain.

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Sv
  • TS
  • Unspecified dB
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Sv
  • TS
  • Unspecified dB

Maximum

This operator returns the maximum data point values from two variables.

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

  • Color
  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB
  • Color
  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB

 

Note: For color variables, comparisons are made using the sum of the red, green and blue channels. If these values are equal, the value from operand 1 is returned.

Mean of 3

This operator takes the mean of three variables.

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

Operand 3

  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB
  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB

     

  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB

 

Note: The mean for SV, TS and unspecified dB variables is calculated in the linear domain.

Minus

This operator subtracts two variables. Operand 2 is subtracted from operand 1.

Echoview accepts operands of the following data types as input:

Operand 1

Operand 2

  • Color
  • Linear
  • Multibeam color
  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Sv
  • TS
  • Unspecified dB
  • Color
  • Linear
  • Multibeam color
  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Sv
  • TS
  • Unspecified dB

Minimum

This operator returns the minimum data point values from two variables.

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

  • Color
  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB
  • Color
  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB

 

Note: For color variables, comparisons are made using the sum of the red, green and blue channels. If these values are equal, the value from operand 1 is returned.

Plus

This operator adds two variables.

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

  • Color
  • Linear
  • Multibeam color
  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Sv
  • TS
  • Unspecified dB
  • Color
  • Linear
  • Multibeam color
  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Sv
  • TS
  • Unspecified dB

Variance of 3

This operator takes the variance of three variables.

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

Operand 3

  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB
  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB
  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB

 

Note: The variance for SV, TS and unspecified dB variables is calculated in the linear domain.

Bitmap operators

Operator

Description

And

This operator does a logical AND on two bitmaps.

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

  • Boolean

  • Multibeam boolean

  • Boolean

  • Multibeam boolean

Line bitmap

Line Bitmap

Line range bitmap

Line range bitmap

Mask

Mask

Not

This operator applies a Boolean NOT operation to the individual values in a Boolean variable, i.e. it changes true values to false and vice-versa.

Echoview accepts a single operand of the following data types as input:

  • Boolean

  • Multibeam boolean

Or

This operator does a logical OR on two bitmaps.

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

  • Boolean

  • Multibeam boolean

  • Boolean

  • Multibeam boolean

Data range bitmap

Data Range Bitmap

Motion range bitmap

Motion Range Bitmap

Region bitmap

Region Bitmap

Select

This operator uses a bitmap to select between values from two other variables.

If there is a true value in the bitmap then the corresponding data value from the first variable will be used at that position, otherwise the corresponding data value from the second variable will be used.

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

Operand 3

  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB
  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB
  • Boolean

Target bitmap

This operator creates a bitmap of pings which contain single target detections.

The resulting virtual variable is a boolean variable with the same number of pings and ping geometry as the first operand. Each sample in the result has a value of true if it is on the same ping as one or more single targets in the second operand and false if not.

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

  • Angular position
  • Boolean
  • Color
  • Complex angular position
  • Complex power dB
  • Complex Sv
  • Complex TS
  • Linear
  • Power dB
  • Pulse compressed complex angular position
  • Pulse compressed complex power dB
  • Pulse compressed complex Sv
  • Pulse compressed complex TS
  • Sv
  • TS
  • Unspecified dB
  • Single targets

Target samples bitmap

Target Samples Bitmap

Conversion operators

Operator

Description

dB to linear

This operator converts dB values in an input variable to linear values using the formula:

linear = 10 (dB / 10)

Echoview accepts a single operand of the following data types as input:

  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Sv
  • TS
  • Unspecified dB

Type conversion

Type Conversion

Linear to dB

This operator applies linear to dB conversion to the individual values in the input variable using the formula:

dB = 10 x log10(linear).

Zero or negative input values are converted to "no data" values.

Echoview accepts a single operand of the following data types as input:

  • Linear 

  • Multibeam Magnitude

Sv to TS

Sv to TS

TS to Sv

TS to Sv

Current velocity component to linear conversion

This operator changes a current velocity component variable to a linear variable.

Echoview accepts a single current velocity component variable as input.

Convolution operators

The Convolution operators group lists single beam convolution operators. Multibeam convolution operators are listed under Multibeam operators.

For more information about convolution operators, their differences, and how they are used, see Convolution algorithms and Convolution operators illustrated.

Operator

Description

3x3 convolution

3x3 Convolution

5x5 convolution

5x5 Convolution

7x7 convolution

7x7 Convolution

XxY convolution

XxY Convolution

XxY statistic

XxY Statistic

XxYxZ convolution

XxYxZ Convolution

Blur

This operator applies a standard 3x3 convolution matrix to blur the image.

The convolution kernel used in the Blur operator is:

1

2

1

2

1

2

1

2

1

 

Echoview accepts a single operand of the following data types as input:

  • Color
  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB

Notes:

Dilation filter n x n

This operator applies an n x n dilation convolution filter to the echogram (where n = 3, 5 or 7).

A dilation filter replaces each data point with the maximum of the data points in the surrounding cell.

Echoview accepts a single operand of the following data types as input:

  • Boolean
  • Color
  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB

Notes:

Erosion filter n x n

This operator applies a n x n erosion filter to the echogram (where n = 3, 5 or 7).

An erosion filter replaces each data point with the minimum of the data points in the surrounding cell.

Echoview accepts a single operand of the following data types as input:

  • Boolean
  • Color
  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB

Notes:

Median filter n x n

This operator applies a n x n median filter to the echogram (where n = 3, 5 or 7).

A median filter replaces each data point with the median of the data points in the surrounding cell.

Echoview accepts a single operand of the following data types as input:

  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB

Notes:

Sharpen

This operator applies a standard 3x3 convolution matrix to sharpen the image.

The convolution kernel used in the Sharpen operator is:

-1

-1

-1

-1

9

-1

-1

-1

-1

 

Echoview accepts a single operand of the following data types as input:

  • Color
  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB

Notes:

Data manipulation operators

Data manipulation operators offer a wide variety of operations for single beam and multibeam data. Other groups list operators that address data manipulation themes.

Operator

Description

Attenuated signal removal

Attenuated Signal Removal

Background noise removal

Background Noise Removal

Calibration subset

Calibration Subset

Cell statistic

Cell Statistic

Cell statistic (Single targets)

Cell Statistic (Single targets)

Copy

This operator copies a variable. It does not change the input variable, but any settings specified on the Data page of the Variable Properties dialog box will be applied.

The resulting virtual variable can be useful for:

  • displaying the "same" variable simultaneously with different display or processing settings

  • thresholding purposes

Echoview accepts operands of the following data types as input:

  • Angular position
  • Boolean
  • Color
  • Complex power dB
  • Complex Sv
  • Complex TS
  • Current velocity
  • Linear
  • Multibeam angular position
  • Multibeam boolean
  • Multibeam color
  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam targets
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Pulse compressed complex angular position
  • Pulse compressed complex power dB
  • Pulse compressed complex Sv
  • Pulse compressed complex TS
  • Single targets
  • Sv
  • Target length
  • TS
  • Unspecified dB

Data generator

Data Generator

Deadzone estimation

Deadzone Estimation

FIR filter
(Finite Impulse Response)

FIR Filter

IIR filter
(Infinite Impulse Response)

IIR Filter

Impulse noise removal

Impulse Noise Removal

Live export

Live Export

Match geometry

Creates a virtual variable that takes data from Operand 1 and the Start range, Stop range, and Number of data points from Operand 2. In effect, it enables you to resample operand 1 to the exact ping geometry of operand 2. The resampling is a weighted mean calculation. This virtual variable is useful to change resampled data back to its original ping geometry. See also: Match geometry algorithm.

Notes:

  • Ping times for operand 1 and 2 must match. See also: Match ping times operator.
  • Echoview offers various Resample operators with more sampling options.

Echoview accepts operands of the following data types as input:

Operand 1:

  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB

Operand 2:

  • Angular position
  • Boolean
  • Color
  • Linear
  • Power dB
  • Pulse compressed complex angular position
  • Sv
  • TS
  • Unspecified dB

Match ping times

Match Ping Times

Merge GPS

This operator merges the position data in two variables to create a single position variable. You can use Merge GPS to merge position data from multiple filesets to partner processed and merged echogram data from multiple filesets.

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

  • Position
  • Position

 

Notes:

  • In the resulting virtual variable, position data are ordered according to time.

  • In the case that position data in both input variables have exactly the same times, the position data from the second variable will be assigned a time 1ms after its original time.

Merge pings

This operator merges the data in two variables of the same data type to create a single variable containing the pings from both the input variables.

Examples of use:

  • merge multiplexed raw variables collected with compatible transducer settings
  • merge corrected data; data may have been time-corrected or corrected in another way

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

  • Angular position
  • Boolean
  • Color
  • Complex angular position
  • Complex power dB
  • Complex Sv
  • Complex TS
  • Current velocity
  • Linear
  • Multibeam angular position
  • Multibeam boolean
  • Multibeam color
  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam targets
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Pulse compressed complex angular position
  • Pulse compressed complex power dB
  • Pulse compressed complex Sv
  • Pulse compressed complex TS
  • Single targets
  • Sv
  • Target length
  • TS
  • Unspecified dB
  • Angular position
  • Boolean
  • Color
  • Complex angular position
  • Complex power dB
  • Complex Sv
  • Complex TS
  • Current velocity
  • Linear
  • Multibeam angular position
  • Multibeam boolean
  • Multibeam color
  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam targets
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Pulse compressed complex angular position
  • Pulse compressed complex power dB
  • Pulse compressed complex Sv
  • Pulse compressed complex TS
  • Single targets
  • Sv
  • Target length
  • TS
  • Unspecified dB

 

 

Notes:

  • In the resulting virtual variable, pings are ordered according to time.
  • In the case that pings in both input variables have exactly the same times, the ping from the second variable will be assigned a time 1ms after its original time. If that time already exists in the virtual variable, Merge pings will add another 0.1 second until a unique and non-identical time is achieved.

Motion correction (Dunford method)

Motion Correction (dunford method)

Ping subset

Ping Subset

Ping time shift

Ping Time Shift

Processed data

This operator applies the exclusions (line and surface) and bad data analysis settings specified on the Analysis page of the Variable Properties dialog box for its input variable. Changes may include: data points to 'no data' values, special handling for Thickness mean calculations and data points to empty water values. For more detailed information refer to About analysis domains.

Echoview accepts a single operand of the following data types as input:

  • Complex power dB
  • Complex Sv
  • Complex TS
  • Linear
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Pulse compressed complex power dB
  • Pulse compressed complex Sv
  • Pulse compressed complex TS
  • Single targets
  • Sv
  • TS
  • Unspecified dB

Reduce pings

This operator is used to remove pings which meet certain criteria.

Echoview accepts a single operand of the following data types as input:

  • Angular position
  • Boolean
  • Color
  • Current velocity
  • Linear
  • Power dB
  • Pulse compressed complex angular position
  • Single targets
  • Sv
  • TS
  • Unspecified dB

 

Notes:

  • Single target pings are dropped if they have no targets.

  • Other pings are removed if:

  • they have no data points, or

  • all values are black (color), all values are false (Boolean), or all values are 'no data' (Sv, TS, dB, linear, current velocity or angle).

  • The number of pings in the Reduced pings echogram can be equal to or less than the input operand.
  • The Reduce pings (Method 2) operator removes pings in a similar way and can offer savings in display time however no-data pings are used at the end of the echogram and this causes an incorrect NASC for the last cell.

Reduce pings (Method 2)

This operator is used to remove pings which meet certain criteria. With respect to the 'reduced pings' for display and export, the Reduce pings and Reduce pings (Method 2) operators are identical.

The differences with the Method 2 operator are:

  • The faster display speed. Pings are calculated only when they are required. In the case where a section of the echogram is displayed, the time savings can be significant. Hence, the Method 2 operator can be useful in developing and testing virtual variable chains.
  • The Method 2 operator differs from the Reduce pings operator in that the Method 2 echogram has the same number of pings as the input operand, but the data is padded with no data values for the number of pings removed by the Reduce pings algorithm. The NASC calculation for the last cell or any region that extends into the last pings of a Reduce pings (Method 2) echogram will be incorrect. To avoid the calculation error, you can use the Ping subset operator to remove the no data pings at the end of the echogram (used for padding).

Echoview accepts a single operand of the following data types as input:

  • Angular position
  • Boolean
  • Color
  • Current velocity
  • Linear
  • Power dB
  • Pulse compressed complex angular position
  • Single targets
  • Sv
  • TS
  • Unspecified dB

Notes:

  • Single target pings are dropped if they have no targets.

  • Other pings are removed if:

  • they have no data points, or

  • all values are black (color), all values are false (Boolean), or all values are 'no data' (Sv, TS, dB, linear, current velocity or angle)

  • The Reduce pings operator removes pings in the same way but the number of pings in the echogram is generally less than the input operand.

Region statistic

Region Statistic

Resample by distance interval

Resample by Distance Interval

Resample by number of pings

Resample by Number of Pings

Resample by time interval

Resample by Time Interval

Threshold

Threshold

Towed body

Towed Body

Transient Noise Removal

Transient Noise Removal

 

Wideband frequency select

Wideband frequency select

 

Wideband frequency subset

Wideband frequency subset

 

Imaging operators

Operator

Description

3 color maximum

3 Color Maximum

GLCM texture feature

GLCM Texture Feature

Monochrome

This operator converts a color echogram to monochrome by averaging the red, green and blue color intensities using the equation:  

       Luminance = 0.2125 * Red + 0.7154 * Green + 0.0721 * Blue

Echoview accepts a single operand of the following data types as input:

  • Color

  • Multibeam color

Notes:

  • The color of data points in virtual variables created using this operator is not affected by the color scheme that is selected for the virtual variable, i.e. they are monochrome representations of the colors that are currently displayed on the operand. Other elements of the color scheme (e.g. lines and regions) are determined by the color scheme selected for the virtual variable.
  • Monochrome algorithm further details.

Overlay

This operator overlays two echograms to create a color image. The second echogram is laid over the first, so that the first is only visible where there are 'no data' values in the second echogram.

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

  • Boolean
  • Color
  • Linear
  • Multibeam boolean
  • Multibeam color
  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Sv
  • TS
  • Unspecified dB
  • Linear
  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam targets
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Single targets
  • Sv
  • TS
  • Unspecified dB

 

Note: The color of data points in virtual variables created using this operator is determined by the operands's color schemes, not by the color scheme of the selected for the virtual variable. Other elements of the color scheme (e.g. lines and regions) are determined by the color scheme selected for the virtual variable, see About setting variable properties for more information.

To Color

This operator converts an echogram to a color image by assigning an RGB (red, green, blue) value to each data point.

Echoview accepts a single operand of the following data types as input:

  • Angular position
  • Boolean
  • Linear
  • Multibeam boolean
  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB
  • Power dB
  • Pulse compressed complex angular position
  • Sv
  • TS
  • Unspecified dB

 

Note: The color of data points in virtual variables created using this operator is determined by the operand's color scheme, not by the color scheme selected for the virtual variable. Other elements of the color scheme (e.g. lines and regions) are determined by the color scheme selected for the virtual variable, see About setting variable properties for more information.

Line operators

Operator

Description

Arithmetic

Creates a virtual line that is the arithmetic sum of the specified operand lines, with the ping time stamps specified by Operand 1. Echoview currently offers the addition or subtraction of line depths for this operator.

The settings for this operator are on the Arithmetic page of the Line Properties dialog box.

Echoview accepts operands with the following data type as input:

Operand 1

  • Complex power dB
  • Complex Sv
  • Complex TS
  • Power dB
  • Pulse compressed complex power dB
  • Pulse compressed complex Sv
  • Pulse compressed complex TS
  • Sv
  • TS
  • Unspecified dB

Operand 2

  • Line

Operand 3

  • Line

Notes:

  • The Arithmetic operator may be used to remove heave from sounder-detected-lines that include it.

Best bottom candidate line pick

Creates a virtual line from an acoustic variable using the Best bottom candidate line pick algorithm and the settings on the Best candidate line pick page of the Line Properties dialog box.

It accepts operands with the following data types:

  • Complex power dB
  • Complex Sv
  • Complex TS
  • Power dB
  • Pulse compressed complex power dB
  • Pulse compressed complex Sv
  • Pulse compressed complex TS
  • Sv
  • TS
  • Unspecified dB

For more information:

Crop

This operator creates a virtual line by cropping the input operand line at a specified minimum and maximum depth.

It accepts operands with the following data types:

  • Line

The settings for this operator are on the Crop page of the Line Properties dialog box.

Note: The Crop operator is useful to pre-process lines that you want to use with the Statistical combination line operator.

Fixed depth

Creates a virtual line with a fixed depth. The settings for this operator are on the Fixed depth page of the Line Properties dialog box. No operand is required.

Linear offset

Creates a virtual line that is linearly offset from another line. The settings for this operator are on the Linear offset page of the Line Properties dialog box.

Echoview accepts a line of any line type as an input operand.

Maximum Sv line pick

Creates a virtual line from an acoustic variable using a Maximum Sv line pick algorithm and the settings on the Maximum Sv Line Pick page of the Line Properties dialog box.

Echoview accepts input operands with the following data types:

  • Complex power dB
  • Complex Sv
  • Complex TS
  • Power dB
  • Pulse compressed complex power dB
  • Pulse compressed complex Sv
  • Pulse compressed complex TS
  • Sv
  • TS
  • Unspecified dB

For more information on the algorithm offered by this operator see the Line Pick algorithms page.

Off-axis angle offset

Creates a virtual line that is at an off-axis angle offset from another line.

The Off-axis angle offset operator makes a translated copy of the input operand line by calculating the equivalent depth change for a specified change in off beam axis angle. This calculation importantly assumes a vertically oriented echosounder and a flat bottom. The transducer draft only is taken from the specified transducer. If the line is based upon a sounder-detected bottom then the transducer associated with that variable is used (another transducer cannot be selected). The settings for this operator are on the Off-axis angle offset page of the Line Properties dialog box.

Echoview accepts a line of any line type as an input operand.

See: About off-axis angle line offsets for more details.

Smoothing filter

Creates a virtual line that is the smoothed version of the operand line.

The settings for this operator are on the Smoothing filter page of the Line Properties dialog box.

Echoview accepts a line of any line type as an input operand.

Span gaps

Creates a virtual line by bridging any gaps from another line. The bridging line segments can be set to a specified line status. The settings for this operator are on the Span Gaps page of the Line Properties dialog box.

Echoview accepts a line of any line type as an input operand.

Statistical combination

Creates a virtual line that is a statistical combination of specified input operand lines with ping time stamps specified by Operand 1. Echoview currently supports mean, maximum, minimum and median depth statistics for this operator. Up to six input lines can be specified. This operator is useful for deriving a single bottom line from bottom lines detected at multiple frequencies.

The settings for this operator are on the Statistical combination page of the Line Properties dialog box.

Echoview accepts operands with the following data type:

Operand 1

Operand 2

  • Line

Operand 3

  • Line

Notes:

Threshold offset

Creates a virtual line offset to another line at the threshold of samples in an acoustic variable. Can be used to detect boundaries such as the end of ring down below the water surface, and vegetation layers above a bottom line. For each ping the algorithm traces downwards or upwards from the original line until a threshold value is reached. The time resolution of Operand 1 dictates the time resolution of the Threshold offset line. As a result, it is advised that the time resolution of Operand 1 and Operand 2 match. Otherwise, unwanted line time-mismatch artifacts may occur.

The settings for this operator are on the Threshold Offset page of the Line Properties dialog box.

Echoview accepts operands with the following data type:

Operand 1

  • Complex power dB
  • Complex Sv
  • Complex TS
  • Power dB
  • Pulse compressed complex power dB
  • Pulse compressed complex Sv
  • Pulse compressed complex TS
  • Sv
  • TS
  • Unspecified dB

Operand 2

  • Line

See also: About the Threshold offset operator.

Time offset

Creates a virtual line by applying a specified time offset to the time of the operand line.

The settings for this operator are on the Time Offset page of the Line Properties dialog box.

Echoview accepts operands with the following data type:

Operand 1

  • Line

Surface operators

Operator

Description

Fixed depth

Creates a surface with a fixed depth.

No operands are required.

The Depth is specified on the Fixed Depth page of the Surface Properties dialog box. Visibility and Notes may also be specified.

Note: Fixed depth surfaces can't be exported or displayed on scenes.

Fixed range

Creates a surface with a fixed range.

No operands are required.

The Range is specified on the Fixed Range page of the Surface Properties dialog box. Visibility and Notes may also be specified.

Note: Fixed range surfaces can't be exported or displayed on scenes.

Movement operators

Operator

Description

Distance correction

Distance Correction

GPS filter

GPS Filter

Kalman GPS smoothing filter

Kalman GPS Smoothing Filter

Scan position

Scan Position

Vessel speed at pings

This operator creates an echogram where the values of all samples within a ping are set to the speed of the vessel at that ping, in nautical miles per hour. Only fixes with a GPS fix status of "good" and pings with "good" position status are used in speed calculations. When no speed is available, the samples of the ping are assigned the special export value of -9999.0

Echoview accepts a single operand of the following data types as input:

  • Linear
  • Power dB
  • Sv
  • TS
  • Unspecified dB

Multibeam operators

The multibeam operators group is not an exhaustive list of operators that can manipulate multibeam data. Operators in other groups may accept multibeam data. For more information refer to Operators that accept multibeam data.

For more information about how Echoview uses the convolution type operators in this group, see Convolution algorithms and Convolution operators illustrated.

Operator

Description

Angle select

Angle Select

Beam select

Beam Select

Beam closing filter 3x3

This operator applies a 3x3 closing filter to each ping of multibeam data.

A closing filter is a dilation followed by an erosion. It smoothes the contours of an image, fuses narrow breaks and long thin gulfs, eliminates small holes, and fills gaps in the contours.

Echoview accepts a single operand of the following data types as input:

  • Multibeam boolean
  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB

Notes:

Beam convolution 3x3

Beam Convolution 3x3

Beam dilation filter 3x3

This operator applies a 3x3 dilation filter to each ping of multibeam data.

Echoview accepts a single operand of the following data types as input:

  • Multibeam boolean
  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB

Notes:

Beam erosion filter 3x3

This operator applies a 3x3 erosion filter to each ping of multibeam data.

Echoview accepts a single operand of the following data types as input:

  • Multibeam boolean
  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB

Notes:

Beam median filter 3x3

This operator applies a 3x3 median filter to each ping of multibeam data.

Echoview accepts a single operand of the following data types as input:

  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB

Notes:

Beam opening filter 3x3

This operator applies a 3x3 opening filter to each ping of multibeam data.

An opening filter is an erosion followed by a dilation. It smoothes the contour of an image, breaks narrow joins between larger areas, and eliminates thin protrusions.

Echoview accepts a single operand of the following data types as input:

  • Multibeam boolean
  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB

Notes:

Beam scan

Beam Scan

Beam subset

Beam Subset

Bottom Echo Bitmap

Bottom Echo Bitmap

Bottom Echo Bitmap H-mode - Furuno

Bottom Echo Bitmap H-mode - Furuno

Double threshold

Double Threshold

Kovesi image denoising

Kovesi Image Denoising

Maximum Intensity

This operator produces a maximum intensity (single beam) echogram from multibeam data, where each sample (at range R) contains the maximum value of all of the corresponding multibeam samples that are at range R.

The maximum intensity echogram can be evaluated against your target conversion variable to ensure that your multibeam target detection settings correctly identify all targets.

This variable could also indicate swim shape and tail-beat frequency of targets, which may be used for species identification. This concept is highly developmental, for further information, refer to use of target range extent to identify swim shape.

Echoview accepts a single variable of the following types as input:

  • Multibeam magnitude
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB

Mean of n previous pings

Mean of N Previous Pings

Median of N pings

Median of N Pings

Minimum of N pings

Minimum of N Pings

Multibeam background removal

Multibeam Background Removal

Multibeam roll at transducer

This operator applies roll from a roll variable to a multibeam variable.

The roll will be applied as if it occurred at the transducer location, and in the same plane as the beam fan. A positive roll rotates the positive major axis clockwise when viewed in the direction of the positive minor axis (that is from the negative minor axis to the positive minor axis).

The operator will give useful results only when the following applies:

  • Firstly, the transducer and roll sensor are physically close to the center of motion of the vessel.

  • Secondly, the beam fan is in the athwartship plane.

Echoview accepts operands of the following data types as input:
 

Operand 1

Operand 2

  • Multibeam angular position
  • Multibeam boolean
  • Multibeam color
  • Multibeam magnitude
  • Multibeam phase
  • Multibeam Sv
  • Multibeam TS
  • Multibeam unspecified dB
  • Roll

See: About roll data for further information.

Multibeam target detection

Multibeam Target Detection

Multibeam target overlay

This operator overlays multibeam targets on the specified multibeam data.

It accepts operands with the following data types:

Operand 1:

  • Multibeam targets

Operand 2:

  • Multibeam Sv

Notes:

  • This operator is designed to be used with virtual variables created with the Multibeam target detection operator.
  • If you want to approximate the visual view from the the Sound Metrics viewer with Sound Metrics data in Echoview, use the Type conversion operator with the Sound Metrics unspecified dB frames variable as Operand 1, and select Sv as the Output type setting on the Type Conversion page of Type conversion virtual variable's Properties dialog box. The Type conversion variable will then be available on the Operand 2 list of the Multibeam target overlay variable.
  • The Filter Targets page is used by this operator.
  • The display of multibeam target data from the first operand is affected by the color scheme of the Multibeam target overlay variable. Similarly, the multibeam target overlay Data tab minimum and maximum color display thresholds control the visibility of overlaid targets.
  • Displayed echogram data from the second operand is affected by the settings of the second operand. It may be necessary to adjust the second operand’s color display settings to improve the viewing of the specified multibeam data under the multibeam target overlay echogram.

Sample statistic subtract

Sample Statistic Subtract

Target conversion

Target Conversion

XxYxZ convolution

XxYxZ convolution

Single target detection operators

See About single target detection for details.

Operator

Description

Single target detection - single beam (method 1)

Single Target Detection - Single Beam (Method 1)

Single target detection - single beam (method 2)

Single Target Detection - Single Beam (Method 2)

Single target detection - split beam (method 1)

Single Target Detection - Split Beam (Method 1)

Single target detection - split beam (method 2)

Single Target Detection - Split Beam (Method 2)

Single target detection - dual beam (method 1)

Single Target Detection - Dual Beam (Method 1)

Single target detection - dual beam (method 2)

Single Target Detection - Dual Beam (Method 2)

Single target detection - wideband

Single Target Detection - Wideband

Single target detection - Furuno FCV-30

This operator outputs FCV-30 single targets found in processed compensated TS data produced by the Furuno FCV-30 sounder.

It accepts operands with the following data types:

Operand 1

Operand 2

  • TS

  • Angular position

Note: A proprietary Furuno beam compensation algorithm is available for use with Single target detection - split beam (Method 1 and Method 2) operators.

Single target manipulation operators

All distance calculations for single target manipulation operators are performed using coordinates that have been adjusted for transducer geometry.

Warning: When you apply a single target manipulation operator, you must, on the Calibration page of the Variable Properties dialog box for the resulting virtual variable, select the same transducer that was selected for the first operand (input variable). If a different transducer is selected, the results may be misleading.

Operator

Description

Target length calculator

Target Length Calculator

Target length conversion

This operator creates a Target length variable from a single targets variable. For each single target the Target Strength is replaced by a Target length value.

The target length values may be obtained from the:

Echoview accepts a single target variable as input.

For more information, refer to:

Target property threshold

Target Property Threshold

TS substitution

TS Substitution

ST difference

ST Difference

ST intersection

ST Intersection

ST union

ST Union

See also

About virtual variables
Data Types

Dataflow window

Variable Properties dialog box

Using multiple operands

Operator licensing in Echoview
Operators that accept multibeam data