NDPluginROI

author:Mark Rivers, University of Chicago

Overview

NDPluginROI selects a rectangular “Region-Of-Interest” (ROI) from the NDArray callback data. The ROI can be any size, from a single array element to the entire array. NDPluginROI  does the following operations, in this order:

  1. Extracts the ROI as defined by its offset (starting array element) and size in each dimension.
  2. Optional binning in any dimension.
  3. Optional orientation reversal (mirroring) in any dimension.
  4. Optional scaling (dividing) by a scale factor.
  5. Optional conversion to a new data type.
  6. Optional collapsing (removing) of dimensions whose value is 1.
  7. Export the ROI as a new NDArray object. The NDPluginROI is both a recipient of callbacks and a source of NDArray callbacks, as a driver is. This means that other plugins like NDPluginStdArrays and NDPluginFile can be connected to an NDPluginROI plugin, in which case they will display or save the selected ROI rather than the full detector driver data.

If scaling is enabled then the array is promoted to a double when it is extracted and binned. The scaling is done on this double-precision array, and then the array is converted back to the desired output data type. This makes scaling relatively computationally intensive, but ensures that correct results are obtained, without integer truncation problems.

Note that while the NDPluginROI should be N-dimensional, the EPICS interface to the definition of the ROI is currently limited to a maximum of 3-D. This limitation may be removed in a future release.

NDPluginROI inherits from NDPluginDriver. The NDPluginROI class documentation describes this class in detail.

NDPluginROI.h defines the following parameters. It also implements all of the standard plugin parameters from NDPluginDriver. The EPICS database NDROI.template provide access to these parameters, listed in the following table. Note that to reduce the width of this table the parameter index variable names have been split into 2 lines, but these are just a single name, for example NDPluginROIName.

Parameter Definitions in NDPluginROI.h and EPICS Record Definitions in NDROI.template
Parameter index variable asyn interface Access Description drvInfo string EPICS record name EPICS record type
NDPluginROI
Name
asynOctet r/w Name of this ROI NAME $(P)$(R)Name
$(P)$(R)Name_RBV
stringout
stringin
ROI definition
NDPluginROI
Dim0Enable
asynInt32 r/w Enable ROI calculations in the X dimension. If not enabled then the start, size, binning, and reverse operations are disabled in the X dimension, and the values from the input array are used. DIM0_ENABLE $(P)$(R)EnableX
$(P)$(R)EnableX_RBV
bo
bi
NDPluginROI
Dim1Enable
asynInt32 r/w Enable ROI calculations in the Y dimension. If not enabled then the start, size, binning, and reverse operations are disabled in the Y dimension, and the values from the input array are used. DIM1_ENABLE $(P)$(R)EnableY
$(P)$(R)EnableY_RBV
bo
bi
NDPluginROI
Dim2Enable
asynInt32 r/w Enable ROI calculations in the Z dimension. If not enabled then the start, size, binning, and reverse operations are disabled in the Z dimension, and the values from the input array are used. DIM2_ENABLE $(P)$(R)EnableZ
$(P)$(R)EnableZ_RBV
bo
bi
NDPluginROI
Dim0Bin
asynInt32 r/w Binning in the X dimension DIM0_BIN $(P)$(R)BinX
$(P)$(R)BinX_RBV
longout
longin
NDPluginROI
Dim1Bin
asynInt32 r/w Binning in the Y dimension DIM1_BIN $(P)$(R)BinY
$(P)$(R)BinY_RBV
longout
longin
NDPluginROI
Dim2Bin
asynInt32 r/w Binning in the Z dimension DIM2_BIN $(P)$(R)BinZ
$(P)$(R)BinZ_RBV
longout
longin
NDPluginROI
Dim0Min
asynInt32 r/w First pixel in the ROI in the X dimension. 0 is the first pixel in the array. DIM0_MIN $(P)$(R)MinX
$(P)$(R)MinX_RBV
longout
longin
NDPluginROI
Dim1Min
asynInt32 r/w First pixel in the ROI in the Y dimension.
0 is the first pixel in the array.
DIM1_MIN $(P)$(R)MinY
$(P)$(R)MinY_RBV
longout
longin
NDPluginROI
Dim2Min
asynInt32 r/w First pixel in the ROI in the Z dimension.
0 is the first pixel in the array.
DIM2_MIN $(P)$(R)MinZ
$(P)$(R)MinZ_RBV
longout
longin
NDPluginROI
Dim0Size
asynInt32 r/w Size of the ROI in the X dimension DIM0_SIZE $(P)$(R)SizeX
$(P)$(R)SizeX_RBV
longout
longin
NDPluginROI
Dim1Size
asynInt32 r/w Size of the ROI in the Y dimension DIM1_SIZE $(P)$(R)SizeY
$(P)$(R)SizeY_RBV
longout
longin
NDPluginROI
Dim2Size
asynInt32 r/w Size of the ROI in the Z dimension DIM2_SIZE $(P)$(R)SizeZ
$(P)$(R)SizeZ_RBV
longout
longin
NDPluginROI
Dim0AutoSize
asynInt32 r/w Automatically set SizeX to the input array size minus MinX DIM0_AUTO_SIZE $(P)$(R)AutoSizeX
$(P)$(R)AutoSizeX_RBV
bo
bi
NDPluginROI
Dim1AutoSize
asynInt32 r/w Automatically set SizeY to the input array size minus MinY DIM1_AUTO_SIZE $(P)$(R)AutoSizeY
$(P)$(R)AutoSizeY_RBV
bo
bi
NDPluginROI
Dim2AutoSize
asynInt32 r/w Automatically set SizeZ to the input array size minus MinZ DIM2_AUTO_SIZE $(P)$(R)AutoSizeZ
$(P)$(R)AutoSizeZ_RBV
bo
bi
NDPluginROI
Dim0MaxSize
asynInt32 r/o Maximum size of the ROI in the X dimension DIM0_MAX_SIZE $(P)$(R)MaxSizeX_RBV longin
NDPluginROI
Dim1MaxSize
asynInt32 r/o Maximum size of the ROI in the Y dimension DIM1_MAX_SIZE $(P)$(R)MaxSizeY_RBV longin
NDPluginROI
Dim2MaxSize
asynInt32 r/o Maximum size of the ROI in the Z dimension DIM2_MAX_SIZE $(P)$(R)MaxSizeZ_RBV longin
NDPluginROI
Dim0Reverse
asynInt32 r/w Reverse ROI in the X dimension. (0=No, 1=Yes) DIM0_REVERSE $(P)$(R)ReverseX
$(P)$(R)ReverseX_RBV
longout
longin
NDPluginROI
Dim1Reverse
asynInt32 r/w Reverse ROI in the Y dimension. (0=No, 1=Yes) DIM1_REVERSE $(P)$(R)ReverseY
$(P)$(R)ReverseY_RBV
longout
longin
NDPluginROI
Dim2Reverse
asynInt32 r/w Reverse ROI in the Z dimension. (0=No, 1=Yes) DIM2_REVERSE $(P)$(R)ReverseZ
$(P)$(R)ReverseZ_RBV
longout
longin
NDPluginROI
DataType
asynInt32 r/w Data type of the ROI (NDDataType_t). This can be different from the data type of the NDArray callback data. ROI_DATA_TYPE $(P)$(R)DataType
$(P)$(R)DataType_RBV
mbbo
mbbi
NDArraySizeX asynInt32 r/o Size of the ROI data in the X dimension ARRAY_SIZE_X $(P)$(R)ArraySizeX_RBV longin
NDArraySizeY asynInt32 r/o Size of the ROI data in the Y dimension ARRAY_SIZE_Y $(P)$(R)ArraySizeY_RBV longin
NDArraySizeZ asynInt32 r/o Size of the ROI data in the Z dimension ARRAY_SIZE_Z $(P)$(R)ArraySizeZ_RBV longin
NDPluginROI
EnableScale
asynInt32 r/w Enable dividing by the Scale value. (0=Disable, 1=Enable). This is very useful when binning or when converting from a higher precision data type to a lower precision data type. For example when binning 2x2, then Scale=4 (dividing by 4) will prevent integer overflow. Similarly, when converting from 16-bit to 8-bit integers one might scale by 256, or perhaps a smaller number if the 16-bit data does not use the full 16-bit range. ENABLE_SCALE $(P)$(R)EnableScale
$(P)$(R)EnableScale_RBV
bo
bi
NDPluginROI
Scale
asynFloat64 r/w The scale value to divide by if EnableScale is enabled. SCALE_VALUE $(P)$(R)Scale
$(P)$(R)Scale_RBV
ao
ai
NDPluginROI
CollapseDims
asynInt32 r/w Collapse (remove) output array dimensions whose value is 1. Consider the case when the input array to the ROI plugin has dimensions [4, 256, 256] and the plugin is configured with MinX=1, SizeX=1, MinY=0, SizeY=256, MinZ=0, SizeZ=256. If CollapseDims=Disable then the output arrays will be of size [1, 256, 256]. If CollapseDims=Enable then the output array will be [256, 256]. This is convenient for some purposes. For example file plugins like JPEG or TIFF will not work with arrays of [1, 256, 256], nor will the ImageJ display plugin. They all require that the array have only 2 dimensions unless it is the special case of 3-D color arrays (RGB1, RGB2, RGB3) where one of the dimensons is 3. COLLAPSE_DIMS $(P)$(R)CollapseDims
$(P)$(R)CollapseDims_RBV
bo
bi

A special case is made when the NDArray data has colorMode=NDColorModeRGB1 or NDColorModeRGB2. In these cases the user interface to the array dimensions is changed so that the Z PVs always refer to the color dimension (as for NDColorModeRGB3), the X dimension refers to the horizontal dimension, and the Y dimension refers to the vertical dimension. This is very convenient, because it means that the ROI does not need to redefined if, for example, the color mode is changed from Mono to RGB1, which would be required if the X, Y and Z dimensions were not automatically switched.

Configuration

The NDPluginROI plugin is created with the NDROIConfigure command, either from C/C++ or from the EPICS IOC shell.

NDROIConfigure(const char *portName, int queueSize, int blockingCallbacks,
               const char *NDArrayPort, int NDArrayAddr,
               int maxBuffers, size_t maxMemory,
               int priority, int stackSize, int maxThreads)

For details on the meaning of the parameters to this function refer to the detailed documentation on the NDROIConfigure function in the NDPluginROI.cpp documentation and in the documentation for the constructor for the NDPluginROI class.

Screen shots

The following MEDM screen provides access to the parameters in NDPluginDriver.h and NDPluginROI.h through records in NDPluginBase.template and NDROI.template.

../_images/NDROI.png

The following MEDM screen provides access to 4 ROIs at once.

../_images/NDROI4.png