2-D Maximum
Compute maximum value of input or sequence of inputs
Libraries:
Computer Vision Toolbox /
Statistics
Description
The 2-D Maximum block identifies the index of the largest element in an input array. The input can be a 1-D vector, 2-D matrix, or an N-D-array. The block can compute the maximum value along a specified dimension of the input or the entire input. The 2-D Maximum block can also track the maximum values in a sequence of inputs over a period of time.
Examples
Replace Intensity Values in ROI with its Maximum Value
Find maximum intensity value of region of interests (ROI) in the input image and replace the pixels in the ROI with its maximum value
Ports
Input
In — Input array
vector | matrix | N-D- array
Input array, specified as a vector, matrix, or N-D- array. This
port is unnamed until you select the Enable ROI processing
parameter or set the Mode parameter to
Running
.
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
| Boolean
| fixed point
Complex Number Support: Yes
Rst — Reset port
scalar
Reset port, specified as a scalar. This port specifies the event that causes the block to reset the running maximum. The sample time of the Rst input must be a positive integer and a multiple of the input sample time.
Dependencies
To enable this port, set the Mode parameter to
Running
and set the Reset port
parameter to Rising edge
, Falling
edge
, Either edge
, or
Non-zero sample
.
Data Types: single
| double
| int8
| int16
| int32
| uint8
| uint16
| uint32
| Boolean
ROI — Region of interest
four-element vector | m-by-4 matrix | M-by-N matrix
Region of interest (ROI), specified as a four-element vector, m-by-4 matrix, or M-by-N matrix. The input value to this port depends on the ROI type parameter.
Note
You can use the ROI
port only if the input is a
matrix.
Dependencies
To enable this port, set the Find the maximum value over
parameter to Entire input
and select the Enable
ROI processing parameter.
Data Types: single
| double
| int8
| int16
| int32
| uint8
| uint16
| uint32
Label — Label matrix
matrix of nonnegative integers
Label matrix, specified as a matrix of nonnegative integers. The label matrix represents the objects in an image. The pixels labeled 0 are the background. The pixels labeled 1 make up one object; the pixels labeled 2 make up a second object; and so on. The size of the label matrix must be the same size as the 2-D input.
Dependencies
To enable this port, select the Enable ROI processing
parameter and set the ROI type parameter to
Label matrix
.
Data Types: uint8
| uint16
| uint32
Label Numbers — Label values of ROIs
M-element vector
Label values of ROIs, specified as a M-element vector. The value of M can be less than or equal to the number of objects that are labeled in the label matrix.
Dependencies
To enable this port, select the Enable ROI processing
parameter and set the ROI type parameter to
Label matrix
.
Data Types: uint8
| uint16
| uint32
Output
Val — Output maximum value
scalar | vector | matrix | N-D-array
Output maximum value, returned as a scalar, vector, matrix, or N-D-array. The size of the returned maximum value depends on the size of the input, and the settings for the Find the maximum value over parameter.
This port is unnamed if Mode is set to
Running
.
Compute Maximum Value of Input Array
The Mode parameter is set to Value and
Index
or Value
. In this case, you can
compute the maximum value along any specified dimension of the input or the entire
input. The output maximum value is a:
Scalar if the input is of any size and Find the maximum value over parameter is set to
Entire input
.Vector if the input is a matrix and the Find the maximum value over parameter is set to any one of
Each row
,Each column
, andSpecified dimension
. In this case, the Dimension value forSpecified dimension
can be either 1 or 2.(N-1)-D array if the input is an N-D array and the Find the maximum value over parameter is set to
Specified dimension
and the Dimension value is N.N-D array with one singleton dimension if the input is an N-D array and the Find the maximum value over parameter is set to either of
Each row
,Each column
, andSpecified dimension
.Example: For a 3-D input array of size M-by-N-by-P, the dimension of the returned output is:
1-by-N-by-P if you set the Find the maximum value over parameter to
Entire row
.M-by-1-by-P if you set the Find the maximum value over parameter to
Entire column
.M-by-N if you set the Find the maximum value over parameter to
Specified dimension
and the Dimension value to 3.
Compute Maximum Value of Sequence of Inputs
When you set the Mode parameter to
Running
, the block computes the maximum value relative
to each sample in the input sequence. The output is of the same size as the
input.
Data Types: single
| double
| int8
| int16
| int32
| uint8
| uint16
| uint32
| fixed point
Idx — Indices of maximum values in the input array
scalar | vector | matrix | N-D-array
Indices of maximum values in the input array, returned as a scalar, vector, matrix, or N-D-array. The size of the returned indices depends on the size of the input, and the settings for the Find the maximum value over parameter.
To enable this port set the Mode parameter to
Value and Index
or Index
. The
indices returned at the output is a:
Scalar if the input is a N- element vector and Find the maximum value over parameter is set to
Entire input
.Vector if the input is a matrix and the Find the maximum value over parameter is set to any one of
Entire input
,Each row
,Each column
, andSpecified dimension
. In this case, the Dimension value forSpecified dimension
can be either 1 or 2.(N-1)-D array if the input is a N-D array and the Find the maximum value over parameter is set to
Specified dimension
and the Dimension value is N.N-D array with one singleton dimension if the input is an N-D array. In this case the Find the maximum value over parameter is set to
Each row
,Each column
, orSpecified dimension
. In this case, the Dimension value forSpecified dimension
is an integer less than N.Example: For a 3-D input array of size M-by-N-by-P, the dimension of the returned output is:
1-by-N-by-P if you set the Find the maximum value over parameter to
Entire row
.M-by-1-by-P if you set the Find the maximum value over parameter to
Entire column
.M-by-N if you set the Find the maximum value over parameter to
Specified dimension
and the Dimension value to 3.
Note
When a maximum value occurs more than once, the computed index corresponds to
the first occurrence. For example, in the input vector [3 2 1 2
3]
, the maximum value is 3 and the one-based index of the maximum value
is 1
.
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
| Boolean
| fixed point
| enumerated
| bus
Flag — Validation for ROI
0 | 1
Validation for ROI, returned as 0 or 1. The output value signifies if all of the ROIs specified at the input lie within the image bounds. The output value depends on the values of the Output and ROI Type parameters.
ROI Type | Output | Output from Flag port | Description |
| Individual statistics for each
ROI | 0 | ROI is completely outside the input image. |
1 | ROI is either completely or partially inside the input image. | ||
Single statistic for all
ROIs | 0 | ROI is completely outside the input image. | |
1 | ROI is either completely or partially inside the input image. | ||
Label matrix | Individual statistics for each
ROI | 0 | Label number is not in the label matrix. |
1 | Label number is in the label matrix. | ||
Single statistic for all
ROIs | 0 | None of the label numbers are in the label matrix. | |
1 | At least one of the label numbers is in the label matrix. |
Note
If the ROI is partially outside the image, the block computes the variance values only for the portion of the ROI that lies within the image bounds.
Dependencies
To enable this port, select the Output flag indicating if ROI is
within image bounds parameter and set the value of ROI
type parameter to Rectangle
,
Lines
, or Label
Matrix
.
Parameters
Main Tab
Mode — Output mode
Value and Index
(default) | Value
| Index
| Running
Specify the type of output to be returned by the block. Select the output mode as:
Value and Index
to return the maximum values and the corresponding indices in the given input.Value
to return only the computed maximum values.Index
to return only the indices of the maximum values in the given input.Running
to return the maximum values in a sequence of inputs.
Index Base — Index origin
One
(default) | Zero
Specify the index for the first element in the input array. Select the index origin as:
One
for one-based numbering. The range of the index values for the elements in an N-D input array is set to (1, N). For example, the index value for the first element in the matrix is set to (1,1).Zero
for zero-based numbering. The range of the index value for the elements in an N-D input array is set to (0, N-1). For example, the index value for the first element in the matrix is set to (0,0).
Find the maximum value over — Dimension along which maximum is computed
Entire input
(default) | Each row
| Each column
| Specified dimension
Specify the dimension of the input along which the block computes the maximum.
Entire input
— Computes maximum over the entire input.Each row
— Computes maximum over each row.Each column
— Computes maximum over each column.Specified dimension
— Computes maximum over the dimension specified in the Dimension parameter.If Dimension is 1, the output is the same as when you select
Each column
.If Dimension is 2, the output is the same as when you select
Each row
.
Dependencies
To enable this parameter, set the Mode parameter to
Value and Index
, Value
, or
Index
.
Dimension — Custom dimension
1 (default) | scalar
Specify the dimension of the input array over which the maximum is computed as a one-based value. The value of this parameter must be greater than 0 and less than or equal to the number of dimensions in the input array.
Dependencies
To enable this parameter, set the Find the maximum value over
parameter to Specified dimension
.
Reset port — Reset event
None
(default) | Rising edge
| Falling edge
| Either edge
| Non-zero sample
Specify when the block detects a reset event. The block resets the running mode when a reset event is detected at the optional Rst port. The reset sample time must be a positive integer and a multiple of the input sample time.
Specify the reset event as:
None
to disable the Rst port.Rising edge
to trigger a reset event when the Rst input does one of the following:Rises from a negative value to either a positive value or zero
Rises from zero to a positive value, where the rise is not a continuation of a rise from a negative value to zero
Falling edge
to trigger a reset event when the Rst input does one of the following:Falls from a positive value to either a negative value or zero
Falls from zero to a negative value, where the fall is not a continuation of a fall from a positive value to zero
Either edge
to trigger a reset event when the Rst input is aRising edge
orFalling edge
.Non-zero sample
to trigger a reset event at each sample time, when the Rst input is not zero.Note
When running simulations in the Simulink® multitasking mode, reset signals have a one-sample latency. Therefore, when the block detects a reset event, there is a one-sample delay at the reset port rate before the block applies the reset.
Dependencies
To enable this parameter, set the Mode parameter to
Running
.
ROI Processing
Enable ROI processing — Compute maximum value within a particular region
off (default) | on
Select to calculate maximum within a particular ROI in the image.
Note
Full ROI processing is available only if you have a Computer Vision Toolbox™ license. If you do not have a Computer Vision Toolbox license, you can still use ROI processing, but the ROI
type is limited to Rectangles
.
Dependencies
To enable this parameter, set the Find the maximum value over
parameter to Entire input
.
ROI type — Type of ROI
Rectangles
(default) | Lines
| Label matrix
| Binary mask
Specify the type of ROI that represents the regions in the image over which the block computes the variance. The type of ROI can be a rectangle, line, label matrix, or a binary mask.
Parameters | Description | |
ROI type | Inputs to the ROI port | |
Rectangles |
|
|
Lines |
|
|
Label matrix | M-by-N matrix | Matrix of the same size as the input image. The matrix contains label values that represent different objects in an image. The pixels labeled 0 are the background. The pixels labeled 1 make up one object; the pixels labeled 2 make up a second object; and so on. |
Binary mask | M-by-N matrix | Matrix of the same size as the input image. The binary mask classifies image pixels as belonging to either the region of interest or the background. The mask pixel values of 1 indicate that the image pixel belongs to the ROI. The mask pixel values of 0 indicate that the image pixel is part of the background. |
Dependencies
To enable this parameter, set the Find the maximum value over
parameter to Entire input
and select the Enable
ROI processing parameter.
ROI portion to process — Portion of ROI in which to calculate maximum
Entire ROI
(default) | ROI perimeter
Specify the portion of the ROI from which the block has to calculate 2-D maximum. The ROI portion is either the entire ROI or the ROI perimeter.
Dependencies
To enable this parameter, select the Enable ROI processing
parameter and set the ROI type parameter to
Rectangles
.
Output — Calculate maximum for individual or entire ROI
Individual statistics for each
ROI
(default) | Single statistic for all ROIs
Specify whether to calculate 2-D maximum individually for each ROI or for the entire ROI.
If you select
Individual statistics for each ROI
, the block outputs a vector of maximum values. The size of the output vector is equal to the number of ROIs.If you select
Single statistic for all ROIs
, the block outputs a scalar value. The scalar value represents the statistical value for all the specified ROIs.
Dependencies
To enable this parameter, select the Enable ROI processing
parameter and set the ROI type parameter to
Rectangles
, Lines
, or
Label matrix
.
Output flag indicating if ROI is within image bounds — Enable Flag port
off (default) | on
Select to expose the Flag port. For a description of the Flag port output, see Flag.
Dependencies
To enable this parameter, select the Enable ROI processing
parameter and set the ROI type parameter to
Rectangles
, Lines
, or
Label matrix
.
Data Types Tab
For details on the fixed-point block parameters, see Specify Fixed-Point Attributes for Blocks (DSP System Toolbox).
Lock data type settings against change by the fixed-point tools — Prevent fixed-point tools from overriding data types
off (default) | on
Select this parameter to prevent the fixed-point tools from overriding the data types you specify in this block. For more information, see Lock the Output Data Type Setting (Fixed-Point Designer).
Block Characteristics
Data Types |
|
Multidimensional Signals |
|
Variable-Size Signals |
|
More About
Maximum value of complex inputs
For complex inputs, the block computes the squared magnitude value for the elements in the input array. The squared magnitude value for a complex number is computed as . The array element with maximum squared magnitude is the maximum value of the input array.
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.
Version History
Introduced in R2011a
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