2-D Minimum
Find minimum values in input or sequence of inputs
Libraries:
Computer Vision Toolbox /
Statistics
Description
The 2-D Minimum block identifies the value, and optionally the position, of the smallest
element in the input. The input can be a vector, a matrix, or an N-D array.
The block identifies the minimum value either along a specified dimension of the input or
across the entire input. It also tracks the minimum values in a sequence of inputs over a
period of time when the Mode parameter is set to
Running
.
Examples
Find Minimum Value in ROI
Calculate the minimum value in an image ROI by using the 2-D
Minimum
block. By using the minimum value, the model removes indistinct pixels in the image regions.
Ports
Input
In — Input array
scalar | vector | matrix | N-D array
Input array, specified as a vector, matrix, or N-D array.
Dependencies
The port is named only when you either select Enable ROI
processing parameter or set the Mode parameter to
Running
.
Data Types: single
| double
| int8
| int16
| int32
| uint8
| uint16
| uint32
| fixed point
Complex Number Support: Yes
Rst — Reset running minimum
scalar
Reset the running minimum, specified as a scalar. This port specifies the event that causes the block to reset the running minimum. The sample time of the Rst input must be a positive integer and a multiple of the block 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. This port accepts different input values depending on the setting of the ROI type parameter.
Note
You can use the ROI port only if the input to the In port is a 2-D image.
You cannot use the ROI port if the Mode parameter is set to
Running
.
Dependencies
To enable this port, set the Find the minimum value over
parameter to Entire input
and select the Enable
ROI processing parameter.
Data Types: single
| double
| int8
| int16
| int32
| uint8
| uint16
| uint32
| Boolean
| fixed point
Label — Label matrix
matrix of nonnegative integers
Label matrix, specified as a matrix of nonnegative integers. The label matrix
represents the objects in a 2-D image. The pixels labeled 0
are the
background. The pixels labeled 1
make up the first object, the
pixels labeled 2
make up the second object, and so on. The size of
the label matrix must be same as the size of the 2-D input image.
Dependencies
To enable this port, select the Enable ROI processing
parameter and set the ROI type parameter to
Label matrix
.
Note
You cannot enable the Label port if the Mode
parameter is set to Running
.
Data Types: uint8
| uint16
| uint32
Label Numbers — Label values of ROIs
M-element vector
Label values of ROI, specified as an M-element vector. This represents the object names for the corresponding numbers in the label matrix. M must be less than or equal to the number of objects in the label matrix.
Dependencies
To enable this port, select the Enable ROI processing
parameter and set the ROI type parameter to
Label matrix
.
Note
You cannot enable the Label Numbers
port if the
Mode parameter is set to
Running.
Data Types: uint8
| uint16
| uint32
Output
Val — Minimum values of input
scalar | vector | matrix | N-D array
Minimum values of the input, returned as a scalar, vector, matrix, or N-D array. The size of this output depends on the size of the input, and the settings of the Mode and Find the minimum value over parameters.
Note
This port is unnamed if the Mode parameter is set to
Running
. It doesn't appear if the
Mode parameter is set to
Index
.
Compute Minimum Value of Input Array
Set the Mode parameter to Value and
Index
or Value
. The block computes the
minimum value along the specified dimension of the input or across the entire input.
The size of the output minimum value depends on the size of the input and the
setting of the Find the Minimum value over parameter.
Scalar — The input is of any size, and the Find the minimum value over parameter is set to
Entire input
.Vector — The input is a matrix, and the Find the minimum value over parameter is set to
Each row
,Each column
, orSpecified dimension
. IfSpecified dimension
is selected, the value of the Dimension parameter must be either1
or2
.(N–1)-D array — The input is an N-D array, the Find the minimum value over parameter is set to
Specified dimension
, and the value of the Dimension parameter is N.N-D array with one singleton dimension — The input is an N-D array, and the Find the minimum value over parameter is set to
Each row
,Each column
, orSpecified dimension
. IfSpecified dimension
is selected, the value of the Dimension parameter must be 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 minimum value over parameter to
Entire row
.M-by-1-by-P if you set the Find the minimum value over parameter to
Entire column
.M-by-N if you set the Find the minimum value over parameter to
Specified dimension
and the Dimension parameter to3
.
Compute Minimum Value of Sequence of Inputs
Set the Mode parameter to
Running
. The block finds the minimum value of all the
inputs in the given sequence and compiles them into a single array. 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 minimum values in the input
scalar | vector | matrix | N-D array
Indices of the minimum values in the input array, returned as a scalar, vector, matrix, or N-D array.
To enable this port, set the Mode parameter to
Value and Index
or Index
.The
size of the output depends on the size of the input and the setting of the
Find the minimum value over parameter.
Scalar — The input is an N-element vector, and the Find the minimum value over parameter is set to
Entire input
.Vector — The input is a matrix, and the Find the minimum value over parameter is set to
Entire input
,Each row
,Each column
, orSpecified dimension
. IfSpecified dimension
is selected, the value of the Dimension parameter must be either1
or2
.(N–1)-D array — The input is an N-D array, the Find the minimum value over parameter is set to
Specified dimension
, and the value of the Dimension parameter is N.N-D array with one singleton dimension — The input is an N-D array, and the Find the minimum value over parameter is set to
Each row
,Each column
, orSpecified dimension
.IfSpecified dimension
is selected, the value of the Dimension parameter must be 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 minimum value over parameter to
Entire row
.M-by-1-by-P if you set the Find the minimum value over parameter to
Entire column
.M-by-N if you set the Find the minimum value over parameter to
Specified dimension
and the Dimension parameter to3
.
Note
When a minimum value occurs more than once, the computed index corresponds to
the first occurrence. For example, if the input vector is [3 2 1 2
1]
, then the minimum value is 1
and the one-based
index of the minimum value is 3
.
Data Types: single
| double
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
| fixed point
Flag — ROI Validation
scalar | vector
ROI Validation, returned as a scalar or vector of logical 1
s
(true
) or 0
s (false
). If
the ROI type parameter is set to
Rectangles
or Lines
, the
output signifies whether or not the specified ROIs lie completely or partially within
the input image. If the ROI type parameter is set to
Label matrix
, the output signifies whether or not the
label numbers specified in the Label Numbers input are present in
the input label matrix.
ROI type | Individual statistics for each ROI | Single statistics for all ROIs |
Rectangles | The port returns an m element vector,
wherem is the number of rows in the
m-4 matrix in the input to the ROI
port. Each element of this vector is a 1 or
0 , indicating that the rectangular ROI is either
completely or partially inside the input image (1 ) or
completely outside the input image (0 ). | The port returns a scalar. The scalar is a 1 or
0 , indicating that any of the rectangles in the
ROI input is present completely or partially inside
(1 ) or completely outside (0 ) the
input image. |
Lines | The port returns a scalar. The scalar is a 1 or
0 , indicating that the input given to the
ROI port is either completely or partially inside
(1 ) the input image or completely outside
(0 ) the input image. | The port returns a scalar. The scalar is a 1 or
0 , indicating that the input given to the
ROI port is either completely or partially inside
(1 ) the input image or completely outside
(0 ) the input image. |
Label matrix | The port returns an M-element vector, where
M is the number of elements in the input to the
Label Numbers port. Each element of the vector is a
1 or 0 , indicating that the
associated label from the Label Numbers input is
present in (1 ) or absent from (0 ) the
Label Matrix input. | The port returns a scalar. The scalar is a 1 or
0 , indicating that any of the labels in the
Label Numbers input are present in
(1 ) or all are absent from (0 ) the
Label Matrix input. |
Note
If the ROI is partially outside the image, the block computes the statistical values for only 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 the ROI
type parameter to Rectangle
, or
Lines
, or select the Output flag indicating
if input label numbers are valid parameter and set the value of
ROI type parameter toLabel
matrix
.
Parameters
Main
Mode — Output mode
Value and Index
(default) | Value
| Index
| Running
Specify the output mode of the block as one of these options.
Value and Index
— Return both the minimum values and their corresponding indices in the given input.Value
— Return only the minimum values.Index
— Return only the indices of the minimum values in the given input.Running
— Tracks the minimum values in a sequence of inputs.
Index Base — Index for first element
One
(default) | Zero
Specify the index for the first element in the input array.
One
for one-based numbering. The range of index values for each dimension is 1 to m, where m is the length of that dimension. For example, the index of the first element in a matrix is (1,1
).Zero
for zero-based numbering. The range of index values for each dimension is 0 to m–1, where m is the length of that dimension. For example, the index of the first element in a matrix is (0,0
).
Find the minimum value over — Dimension along which minimum is computed
Entire input
(default) | Each row
| Each column
| Specified dimension
Specify the dimension of the input along which the block computes the minimum.
Entire input
— Computes minimum over the entire input.Each row
— Computes minimum over each row.Each column
— Computes minimum over each column.Specified dimension
— Computes minimum over the dimension specified in the Dimension parameter.If the Dimension parameter is set to
1
, the output is the same as whenEach column
is selected.If the Dimension parameter is set to
2
, the output is the same as whenEach row
is selected.
Dependencies
To enable this parameter, set the Mode parameter to
Value and Index
, Value
, or
Index
.
Dimension — Custom dimension
1
(default) | positive scalar
Specify the dimension of the input array over which the block computes the minimum as a one-based value. The value of this parameter must be greater than zero and less than or equal to the number of dimensions in the input array.
Dependencies
To enable this parameter, set the Find the minimum value over
parameter to Specified dimension
.
Reset port — Reset event
None
(default) | Rising edge
| Falling edge
| Either edge
| Non-zero sample
Specifies what the block detects as a reset event. The block resets the running minimum when a reset event is detected at the Rst port. The reset sample time must be a positive integer and a multiple of the input sample time.
Specify the reset event as one of these options.
None
— Disable the Rst port.Rising edge
— 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
— 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
— Trigger a reset event when the Rst input is either aRising edge
or aFalling edge
.Non-zero sample
— Trigger a reset event at each sample time, where the Rst input is not zero.Note
When running simulations in Simulink® multitasking mode, reset signals have a one-sample latency. In this case, when the block detects a reset event, there is a one-sample delay at the Rst port rate before the block applies the reset.
Dependencies
To enable this parameter, set the Mode parameter to
Running
.
Enable ROI processing — Compute minimum value within ROI
off
(default) | on
Select to calculate the minimum within an 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 parameter is limited to
Rectangles
.
Dependencies
To enable this parameter, set the Find the minimum value over
parameter to Entire input
.
ROI type — Format of ROI
Rectangles
(default) | Lines
| Label matrix
| Binary mask
Specify the ROI format that represents the regions in the image over which to compute the minimum. The type of ROI can be a rectangle, line, label matrix, or a binary mask.
ROI type | Inputs to the ROI port | Description |
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.
Binary mask values of 1 indicate that the corresponding
image pixel belongs to the ROI. Binary mask values of 0
indicate that the corresponding image pixel is part of the background. |
Dependencies
To enable this parameter, set the Find the minimum value over
parameter to Entire input
and select the Enable
ROI processing parameter.
ROI portion to process — Portion of ROI in which to calculate minimum
Entire ROI
(default) | ROI perimeter
Specify the portion of the ROI for which the block calculates the 2-D minimum.
Entire ROI
— The block computes the minimum value over the entire region of the rectangular ROI.ROI perimeter
— The block computes the minimum value along the perimeter of the rectangular ROI.
Dependencies
To enable this parameter, select the Enable ROI processing
parameter and set the ROI type parameter to
Rectangles
.
Output — Calculate individual or universal minimum for ROIs
Individual statistics for each
ROI
(default) | Single statistic for all ROIs
Specify whether to calculate the 2-D minimum individually for each ROI or across all ROIs.
If you select
Individual statistics for each ROI
, the block outputs a vector of minimum values, each element representing an ROI. 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 is the minimum value across all 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 enable the Flag output port.
Note
The name of this parameter changes to Output flag indicating if input
label numbers are valid when the ROI type
parameter is set to Label matrix
.
Dependencies
To enable this parameter, select the Enable ROI processing
parameter and set the ROI type parameter to
Rectangles
, or Lines
.
Data Types
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 |
|
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.
Version History
Introduced before R2006a
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