Operators

Operator

Description

Code

The multi-threaded Code operator allows you to apply a Python® script from a *.py file to specified operands. Echoview supports and includes the Python NumPy and SciPy modules which offer a wide range of open-source scientific computing and numerical integration capabilities. The Code operator is licensed under the Advanced Operators module.

The Code operator outputs a ping for each matched operand ping. The data type of the output is the same as the operand. However, the Complex power dB, Complex Sv, Complex TS, Pulse compressed complex power dB, Pulse compressed complex Sv, Pulse compressed complex TS data types are output as single beam Sv, TS and power respectively. Calculations are carried out in the domain specified by the Python file.

See also: Code settings and further notes.

Constant divide

This operator divides a variable by a constant number. The Constant divide operator is licensed under the Advanced Operators module.

See also: Constant Divide settings and further notes.

Constant multiply

This operator multiplies a variable by a constant number. The Constant mulitply operator is licensed under the Advanced Operators module.

See also: Constant Multiply settings and further notes.

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. The Current velocity magnitude operator is licensed under the Advanced Operators module.

Echoview accepts operands of the following data types as input:
 

Formula

This operator runs an arbitrary mathematical equation on a per-sample basis on the echogram data. The Formula operator is licensed under the Advanced Operators module. The operator may handle many operands.

See also: Formula settings and further notes.

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:
 

Linear plus

This operator adds two variables in the linear domain.

Echoview accepts operands of the following data types as input:
 

Maximum

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

Echoview accepts operands of the following data types as input:
 

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:
 

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:

Notes:

• Output for ping 0 is no data for the case where the Operand 2 variable is made up of all no data pings.
• Effect of No data samples on the Wideband Frequency Response graph page.

Minimum

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

Echoview accepts operands of the following data types as input:
 

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:
 

Notes:

• Output for ping 0 is no data for the case where the Operand 2 variable is made up of all no data pings.
• Effect of No data samples on the Wideband Frequency Response graph page.

Variance of 3

This operator takes the variance of three variables.

Echoview accepts operands of the following data types as input:
 

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

Operator

Description

And

This operator does a logical AND on two bitmaps.

Echoview accepts operands of the following data types as input:
 

Line bitmap

This operator is used to create a bitmap of the area between two specified lines.
The input variable is used to determine the ping times and ping geometry.

See also: Line Bitmap settings and notes.

Line range bitmap

This operator creates a bitmap using the ping geometry of operand 1. Every datapoint in each output ping will be true if the line depth (from operand 2) at the time of that ping was within the specified limits, and false otherwise.

See also: Line range bitmap and notes.

Mask

This operator applies a bitmap mask to another variable. Data corresponding to true values in the bitmap are unchanged. Data corresponding to false values in the bitmap will be converted to the value specified on the Mask page of the Variable Properties dialog.

All operands must be exclusively single beam or multibeam.

See also: Mask settings and notes.

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.

Or

This operator does a logical OR on two bitmaps.

Data range bitmap

This operator creates a bitmap (Boolean or multibeam Boolean variable) with a "true" value for each input value that is within a specified range, and a "false" value for each input value that is outside the specified range. "No data" values are always translated to "false".

See also: Data Range Bitmap settings and notes.

Motion range bitmap

This operator creates a bitmap using the ping geometry of operand 1. Every datapoint in each output ping will be true if the roll, pitch or heading (from operand 2) at the time of that ping was within the specified limits, and false otherwise.

See also: Motion Range Bitmap settings and notes.

Region bitmap

This operator is used to create a bitmap of the area corresponding to regions of specified type and/or classification. The input variable is used to determine the ping times and ping geometry.

See also: Region Bitmap settings and notes.

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.
 

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. See also Effect of No data samples on the Wideband Frequency Response graph page.

Target samples bitmap

This operator creates a Boolean (bitmap) variable which has the same ping geometry as the first operand. The datapoint values are false, when samples on a ping in the first operand do not fall within the range of a single target (specified by the Near margin and Far margin) in the corresponding ping of the second operand.

See also: Target Samples Bitmap settings and notes.

Trained model bitmap (experimental)

This operator creates a bitmap using a trained inference model that represents a chosen feature in an acoustic variable. This is an experimental operator that uses machine learning techniques.

See also: Trained model bitmap (experimental) settings and notes.

Operator

Description

dB to linear

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

linear = 10 (dB / 10)

Type conversion

This operator is used for changing the data type of a variable to a different data type. This operator does not, by itself, change the input variable. However, any settings specified on the Data page of the Variable Properties dialog box will be applied.

See also: Type Conversion settings and notes.

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.

Sv to TS

This operator applies Sv to TS conversion to the individual dB values in the input variable.

See also: Sv to TS settings and notes.

TS to Sv

This operator applies TS to Sv conversion to the individual dB values in the input variable.

See also: TS to Sv settings and notes.

Current velocity component to linear conversion

This operator returns the magnitude of the current velocity given three orthogonal current velocity component variables.

Operator

Description

3x3 convolution

This operator applies a user-specified 3x3 convolution matrix to the echogram.

See also: 3x3 Convolution settings and notes.

5x5 convolution

This operator applies a user-specified 5x5 convolution matrix to the echogram.

See also: 5x5 Convolution settings and notes.

7x7 convolution

This operator applies a user-specified 7x7 convolution matrix to the echogram.

See also: 7x7 Convolution settings and notes.

XxY convolution

This operator applies an XxY convolution algorithm to the echogram.

See also: XxY Convolution settings and notes.

This operator applies an XxY statistic filter to the echogram.

See also: XxY Statistic settings and notes.

XxYxZ convolution

This operator applies an XxYxZ convolution algorithm to the echogram.

See also: XxYxZ Convolution settings and notes.

XxYxZ statistic

This operator applies an XxYxZ statistic filter to the echogram.

See also: XxYxZ Statistic settings and notes.

Blur

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

The convolution kernel used in the Blur operator is:

Notes:

• Under live viewing, the Live Export based on a convolution variable may be limited.
• Convolution algorithms: Sliding window and kernel.
• Convolution operators illustrated.

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.

Notes:

• Under live viewing, the Live Export based on a convolution variable may be limited.
• Convolution filters.
• Convolution operators illustrated.

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.

Notes:

• Under live viewing, the Live Export based on a convolution variable may be limited.
• Convolution filters.
• Convolution operators illustrated.

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.

Notes:

• Under live viewing, the Live Export based on a convolution variable may be limited.
• Convolution filters.
• Convolution operators illustrated.

Sharpen

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

The convolution kernel used in the Sharpen operator is:

Notes:

• Under live viewing, the Live Export based on a convolution variable may be limited.
• Convolution algorithms: Sliding window and kernel.
• Convolution operators illustrated.

Operator

Description

Attenuated signal removal

This operator identifies pings which show an attenuated signal strength when compared to the surrounding pings. The operator is based on the “attenuated signal filter” algorithm and definitions described in Ryan et al. (2015).

See also: Attenuated Signal Removal settings and notes.

Background noise estimation

This operator estimates the background-noise level. Background noise manifests as a ‘TVG rainbow’ on an echogram. The operator is based on the algorithm and definitions described in De Robertis & Higginbottom (2007).

See also: Background Noise Estimation settings and notes.

Background noise removal

This operator estimates the background-noise level and subtracts it from the value of each sample. Background noise manifests as a ‘TVG rainbow’ on an echogram.

See also: Background Noise Removal settings and notes.

Calibration subset

This operator creates a variable containing the subset of pings that have a specified calibration value.

See also: Calibration Subset settings and notes.

Cell statistic

This operator produces an output variable with samples set based on a statistic calculated from each cell.

See also: Cell Statistic settings and notes.

Cell statistic [Single targets]

This operator produces an output variable with samples set based on a statistic calculated from each cell. Operand 2 is used to provide the geometry for the output ping, but note that ping times must still match.

See also: Cell Statistic [Single targets] settings and notes.

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

Note: See also Effect of No data samples on the Wideband Frequency Response graph page.

Data generator

This operator is used to create data pings. It can create pings with constant values using a specified value. It can also create Sv and TS pings with time-varied gain (TVG), based on the Sv or TS value at 1 meter and a specified absorption coefficient. The input variable is used to determine the ping times and ping geometry.

See also: Data Generator settings and notes.

Deadzone estimation

This operator calculates estimations for the Sv values in the deadzone, a zone on the echogram specified by two lines. Each data sample in the deadzone is replaced by the average of all values in a layer with specified thickness above the deadzone.

See also: Deadzone Estimation settings and notes.

FIR filter
(Finite Impulse Response)

This operator implements a finite impulse response filter. It returns a weighted average of the current and previous pings.

See also: FIR Filter settings and notes.

IIR filter
(Infinite Impulse Response)

This operator implements an infinite impulse response filter. It returns a weighted average of the current ping and the calculated previous ping.

See also: IIR Filter settings and notes.

Impulse noise removal

This operator identifies and adjusts sample values that are significantly higher than those of surrounding samples at the same depth.

Based on the combination of settings applied, it can be used to adjust the value of samples that are affected by impulse noise such as interference from other sonars (which manifest as short ‘flecks’ on an echogram). Care is required to prevent it from adjusting good data.

The operator is based on the “impulsive noise (IN)” algorithm and definitions described in Ryan et al. (2015).

See also: Impulse Noise Removal settings and notes.

Join opposing pings

Joins the ping data from two transducers which are pinging in opposite directions. The ping data from operand 2 is projected onto the ping data from operand 1.

See also: Join Opposing Pings settings and further notes.

Live export

This operator incrementally exports its data to a file during live viewing.

See also: Live Export settings and notes.

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

Match ping times

This operator selects pings from the first operand in such a way as to match the times of the pings in the second operand.

See also: Match Ping Times settings and notes.

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:
 

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

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.
• See also Effect of No data samples on the Wideband Frequency Response graph page.

Motion correction (Dunford method)

This operator compensates sample values for attenuation due to changes in orientation of the transducer between the time of the transmitted pulse and the time of each sample's reception.

See aslo: Motion correction (Dunford method) settings and notes.

Ping subset

This operator creates a variable containing a specified subset of the pings in another variable.

See aslo: Ping Subset settings and notes.

Ping time shift

This operator makes a copy of another variable, shifting the time on each ping by a specified time or to times corresponding to a relative ping index.

See also: Ping Time Shift settings and notes.

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. Also note the Effect of No data samples on the Wideband Frequency Response graph page.

Reduce pings

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

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.
• See also Effect of No data samples on the Wideband Frequency Response graph page.

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).

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.
• See also Effect of No data samples on the Wideband Frequency Response graph page.

Region statistic

This operator is used to fill the datapoints in matching regions with a statistic calculated on the first operand for those regions. Datapoints in overlapping matching regions will be assigned a "no data" value.

See also: Region Statistic settings and notes.

Resample by distance interval

This operator resamples the input variable using a fixed distance interval in the time/distance domain, and a specified upper range, lower range and number of datapoints in the range domain. You may choose to sample all datapoints, or only those from the ping at the center of each interval. A mean, median, maximum, minimum or percentile resampling operation can be performed.

See also: Resample by Distance Interval settings and notes.

Resample by number of pings

This operator resamples the input variable using a fixed number of pings in the time/distance domain, and a specified upper range, lower range and number of datapoints in the range domain. You may choose to sample all datapoints, or only those from the ping at the center of each interval. A mean, median, maximum, minimum or percentile resampling operation can be performed.

See also: Resample by Number of Pings settings and notes.

Resample by time interval

This operator resamples the input variable using a fixed time interval in the time/distance domain, and a specified upper range, lower range and number of datapoints in the range domain. You may choose to sample all datapoints, or only those from the ping at the center of each interval. A mean, median, maximum, minimum or percentile resampling operation can be performed.

See also: Resample by Time Interval settings and notes.

Resample multibeam pings

This operator resamples the input variable using a fixed number of beams (with specified minimum/maximum beam angles) and a fixed number of datapoints (with specified start/stop range). A mean, median, maximum, minimum or percentile resampling operation can be performed.

The resampled virtual variable can then be used with multibeam operators (e.g., Multibeam Background Removal) that require a regular ping geometry across pings.

Refer to Resample multibeam page for details on the settings for this operator.

Signal to background noise ratio

This operator estimates the ratio between the signal and the background-noise level for each sample in decibels. Background noise manifests as a ‘TVG rainbow’ on an echogram.

The operator is based on the algorithm and definitions described in De Robertis & Higginbottom (2007).

See also: Signal to Background Noise Ratio settings and notes.

Threshold

This operator compares datapoint values from two variables. If the Maximum or Minimum threshold is set and the value of a datapoint in Operand 1 is greater or less than the corresponding datapoint value from Operand 2 then the output datapoint is set to a thresholded value selected on the Variable Properties dialog. Otherwise it is set to the value of the datapoint from Operand 1.

All operands must be exclusively single beam or multibeam.

See also: Threshold settings and notes.

Towed body

This operator is used to adjust the start ranges of pings using the depths of a specified line. It is designed for use with downwards-pointing transducers, and lines with positive depths.

The Towed Body operator is only suitable in specific circumstances and has been superceded by heave support in the platform.

See also: Towed Body settings and notes.

Transect_subset

This operator creates a variable containing a subset of the pings in another variable based on transects.

See also: Transect subset settings and notes.

Transient Noise Ping Removal

This operator identifies pings which show an amplified signal strength when compared to the surrounding pings, typically associated with transient noise.

The operator is based on the “attenuated signal filter” algorithm and definitions described in Ryan et al. (2015).

See also: Transient Noise Ping Removal settings and notes.

Transient Noise Sample Removal

This operator identifies and adjusts sample values that are significantly higher than those of surrounding samples.

Based on the combination of settings applied, it can be used to adjust the value of samples that are affected by transient noise such as sound generated by wave-hull collisions (which manifest as long ‘spikes’ on an echogram). Care is required to prevent it from adjusting good data.

The operator is based on the “transient noise (TN)” algorithm and definitions described in Ryan et al. (2015).

See also: Transient Noise Sample Removal settings and notes.

Wideband frequency select

This operator creates a single frequency echogram by suppressing all other frequency components from a wideband acoustic variable. The pulse length is not adjusted in the calculation for this operator, so when used with Sv data, it will result in lower values.

See also: Wideband frequency select settings and notes.

Wideband frequency subset

This operator suppresses the components of the data which lie outside the requested frequency range, for a wideband acoustic variable. The pulse length is not adjusted in the calculation for this operator, so when used with Sv data, it will result in lower values.

See also: Wideband frequency subset settings and notes.

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:
 

Note: The color of data points in virtual variables created using this operator is determined by the operands' 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
• Complex angular position
• Complex power dB
• Complex Sv
• Complex TS
• Linear
• Multibeam boolean
• Multibeam magnitude
• Multibeam phase
• Multibeam Sv
• 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
• Sv
• TS
• Unspecified dB

Notes:

• 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.
• See also Effect of No data samples on the Wideband Frequency Response graph page.

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:

• on the algorithm, see the Best bottom candidate line pick algorithm
• on the topic, see About the Best bottom candidate line pick
• on the settings, see Best bottom candidate settings

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.

Creates a virtual line at the depth corresponding to the estimated on-axis range of the near field (Fresnel zone), multiplied by a factor (default is 2).

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

Notes:

• Echoview recomputes the near-field depth when you change the
• transducer geometry (refer to Near-field depth and transducer geometry)
• Heave
• for Operand 1
• This operator accounts for transducer and platform geometry.
• The Multiply near-field range by setting on the Near-field Depth Estimation page is a factor by which to extend the near-field range that Echoview computes. The default is 2.
• Where the operator encounters invalid operand 1 ping data, the Near-field depth line status is set to None and a value of -10000.99.
• Invalid cases include:
  • an unavailable value for frequency/major-axis 3dB beam angle/minor-axis 3dB beam angle
  • 0° for major-axis 3dB beam angle/minor-axis 3dB beam angle
• CTD data is not supported.

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.

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.

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

• Acoustic variable

Operand 2

• Line

Operand 3

• Line

Notes:

• See Statistical combination operator algorithm for more details.
• When using lines from multiple frequencies or high frequencies, you may need to pre-process input lines with the Crop line operator.

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.

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

Creates a virtual line for the visualization of a towed body's position using an acoustic variable and a depth line. The time offset is calculated relative the platform and considers the platform speed, tow point, tow length and tow depth. See also: Synchronizing towed body media data with echograms.

The settings for this operator are on the Towed Body Time 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

Creates a virtual line using a trained inference model for excluding the bottom in an acoustic variable.

Settings for this operator may be specified on the Trained Model Bottom Exclusion page of the Line Properties dialog box.

Echoview accepts operands with the following data type:

Operand 1

• Sv

Notes:

• This operator employs the Trained model bottom exclusion (experimental) Line picking algorithm
• CTD data is not supported
• The accuracy of this operator depends on how closely your input echogram resembles the bottom exclusion Machine learning training dataset
• This operator benefits from GPU acceleration (refer to Machine learning operator performance)
• Operand pings with the same timestamp produce a poor bottom line

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.

Linear offset

Creates a surface at a fixed distance from an existing surface. The operand and distance are specified on the Surface Properties dialog box.

Note: Linear Offset surfaces cannot be exported or displayed on scenes.

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 smooths 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:

• Convolution filters.
• Convolution operators illustrated.

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:

• Convolution filters.
• Convolution operators illustrated.

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:

• Convolution filters.
• Convolution operators illustrated.

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:

• Convolution filters.
• Convolution operators illustrated.

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 smooths 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:

• Convolution filters.
• Convolution operators illustrated.

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

This operator combines simultaneous ping fans from two operands. Echoview assumes both pings are from the same transducer. All operands must be of the same data type. The Combine fans operator is licensed under the Advanced Operators module.

See also: Combine Fans settings and further notes.

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 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. Note, under the Maximum intensity operator range and depth are the same.

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

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:
 

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 magnitude
• Multibeam Sv
• Multibeam TS
• Multibeam unspecified dB

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 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

Operator

Description

Single target detection - single beam (method 1)

This operator detects single targets using the algorithm implemented by Simrad in the EK500 echosounder.

See also: Single target detection - single beam (method 1) settings and notes.

Single target detection - single beam (method 2)

This operator detects single targets using an algorithm based on Echoview Software's understanding of the single target detection algorithm implemented by Simrad in the EK60 echosounder.

See also: Single target detection - single beam (method 2) settings and notes.

Single target detection - split beam (method 1)

This operator detects single targets using a modified version of the single target detection single beam (method 1) algorithm that applies compensation estimates (based on split-beam angle data) to the peak selection criteria.

See also: Single target detection - split beam (method 1) settings and notes.

Single target detection - split beam (method 2)

This operator detects single targets using a modified version of the single target detection single beam (method 2) operator that applies compensation estimates (based on split-beam angle data) to the peak selection criteria.

See also: Single target detection - split beam (method 2) settings and notes.

Single target detection - dual beam (method 1)

This operator detects single targets using a modified version of the single target detection single beam (method 1) algorithm that applies compensation estimates (based on difference between a narrow beam and wide beam signal) to the peak selection criteria.

See also: Single target detection - dual beam (method 1) settings and notes.

Single target detection - dual beam (method 2)

This operator detects single targets using a modified version of the single target detection single beam (method 2) algorithm that applies compensation estimates (based on the difference between a narrow beam and wide beam signal) to the peak selection criteria.

See also: Single target detection - dual beam (method 2) settings and notes.

Single target detection - wideband

This operator detects single targets for wideband data. It supports both single beam and split-beam data. When operand 2 is Pulse compressed complex angular position the data is assumed to be split beam.

See also Single target detection - wideband settings and notes.

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:

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

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:

• Multibeam target detection operator followed by the Target conversion operator (where target length is the maximum distance between samples in a single target).
• Target length calculator operator (where target length is calculated from TS and species-specific coefficients).

Echoview accepts a single target variable as input.

For more information, refer to:

• About target properties

Target property threshold

Target Property Threshold

TS substitution

TS Substitution

ST difference

ST Difference

ST intersection

ST Intersection

ST union

ST Union