ADSimDetector¶
author:  Mark Rivers (University of Chicago), John Hammonds (Argonne National Laboratory) 

Table of Contents¶
Contents
 ADSimDetector
 Table of Contents
 Introduction
 Simulation driver specific parameters
 Simulation Modes
 Unsupported standard driver parameters
 Configuration
 Example st.cmd startup file
 Screenshots
 simDetector.adl
 Linear Ramp Mode
 Ramp Mode
 Simulation setup screen with Peaks mode selected
 ImageJ display with the above Peaks mode parameters
 Simulation setup screen with simple Sine mode setup
 ImageJ display with the above simple Sine mode parameters
 Simulation setup screen with complex Sine mode parameters
 ImageJ display with the above complex Sine mode parameters
 ImageJ X profile with the above complex Sine mode parameters.
 ImageJ Y profile with the above complex Sine mode parameters.
 Simulation setup screen with Sine mode parameters in RGB1 color mode
 ImageJ display with the above color Sine mode parameters.
Introduction¶
This is an EPICS areaDetector driver for a simulated area detector. The simulation detector is useful as a model for writing real detector drivers. It is also very useful for testing plugins and channel access clients.
This driver inherits from ADDriver. It implements nearly all of the parameters in asynNDArrayDriver.h and in ADArrayDriver.h, with the exception of the file saving parameters, which it does not implement. It also implements a few parameters that are specific to the simulation detector. The simDetector class describes this class in detail.
The writeInt32
and writeFloat64
methods override those in the base
class. The driver takes action when new parameters are passed via
those interfaces. For example, the ADAcquire
parameter (on the
asynInt32
interface) is used to turn acquisition (i.e. computing new
images) on and off.
Simulation driver specific parameters¶
The simulation driverspecific parameters are the following:
Parameter Definitions in simDetector.cpp and EPICS Record Definitions in simDetector.template  

Description  drvInfo string  EPICS record name  EPICS record type 
Gain in the X direction  SIM_GAINX  $(P)$(R)GainX, $(P)$(R)GainX_RBV  ao, ai 
Gain in the Y direction  SIM_GAINY  $(P)$(R)GainY, $(P)$(R)GainY_RBV  ao, ai 
Gain of the red channel  SIM_GAIN_RED  $(P)$(R)GainRed, $(P)$(R)GainRed_RBV  ao, ai 
Gain of the green channel  SIM_GAIN_GREEN  $(P)$(R)GainGreen, $(P)$(R)GainGreen_RBV  ao, ai 
Gain of the blue channel  SIM_GAIN_BLUE  $(P)$(R)GainBlue, $(P)$(R)GainBlue_RBV  ao, ai 
The offset added to the image.  SIM_OFFSET  $(P)$(R)Offset, $(P)$(R)Offset_RBV  ao, ai 
The amount of random noise added to the image.  SIM_NOISE  $(P)$(R)Noise, $(P)$(R)Noise_RBV  ao, ai 
Set to 1 to reset image back to initial conditions  RESET_IMAGE  $(P)$(R)Reset, $(P)$(R)Reset_RBV  longout, longin 
Sets the simulation mode. Options are:

SIM_MODE  $(P)$(R)SimMode, $(P)$(R)SimMode_RBV  mbbo, mbbi 
Parameters for Array of Peaks Mode  
X location of the first peak centroid  SIM_PEAK_START_X  $(P)$(R)PeakStartX, $(P)$(R)PeakStartX_RBV  longout, longin 
Y location of the first peak centroid  SIM_PEAK_START_Y  $(P)$(R)PeakStartY, $(P)$(R)PeakStartY_RBV  longout, longin 
X width of the peaks  SIM_PEAK_WIDTH_X  $(P)$(R)PeakWidthX, $(P)$(R)PeakWidthX_RBV  longout, longin 
Y width of the peaks  SIM_PEAK_WIDTH_Y  $(P)$(R)PeakWidthY, $(P)$(R)PeakWidthY_RBV  longout, longin 
Number of peaks in X direction  SIM_PEAK_NUM_X  $(P)$(R)PeakNumX, $(P)$(R)PeakNumX_RBV  longout, longin 
Number of peaks in Y direction  SIM_PEAK_NUM_Y  $(P)$(R)PeakNumY, $(P)$(R)PeakNumY_RBV  longout, longin 
X step between peaks  SIM_PEAK_STEP_X  $(P)$(R)PeakStepX, $(P)$(R)PeakStepX_RBV  longout, longin 
Y step between peaks  SIM_PEAK_STEP_Y  $(P)$(R)PeakStepY, $(P)$(R)PeakStepY_RBV  longout, longin 
Used to introduce randomness in the peak height. If nonzero then each gaussian peak in the array is assigned a scaling factor: scalingFactor = 1.0 + (rand() % peakVariation + 1) / 100.0

SIM_PEAK_HEIGHT_VARIATION  $(P)$(R)PeakVariation, $(P)$(R)PeakVariation_RBV  longout, longin 
Parameters for Sine Mode  
The operation to use to combine XSine1 and XSine2. Choices are:

SIM_XSIN_OPERATION  $(P)$(R)XSineOperation, $(P)$(R)XSineOperation_RBV  mbbo, mbbi 
The operation to use to combine YSine1 and YSine2. Choices are:

SIM_YSIN_OPERATION  $(P)$(R)YSineOperation, $(P)$(R)YSineOperation_RBV  mbbo, mbbi 
The amplitude of the sine wave. There is a record for each of the 4 sine waves: XSine1, XSine2, YSine1, YSine2.  SIM_[X,Y]SIN[1,2]_AMPLITUDE  $(P)$(R)[X,Y]Sine[1,2]Amplitude, $(P)$(R)[X,Y]Sine[1,2]Amplitude_RBV  ao, ai 
The frequency of the sine wave. A frequency of 1 means there is one complete period of the sine wave across the image in the X or Y direction. There is a record for each of the 4 sine waves: XSine1, XSine2, YSine1, YSine2.  SIM_[X,Y]SIN[1,2]_FREQUENCY  $(P)$(R)[X,Y]Sine[1,2]Frequency, $(P)$(R)[X,Y]Sine[1,2]Frequency_RBV  ao, ai 
The phase of the sine wave in degrees. A phase of 90 is the same as a cosine wave. There is a record for each of the 4 sine waves: XSine1, XSine2, YSine1, YSine2.  SIM_[X,Y]SIN[1,2]_PHASE  $(P)$(R)[X,Y]Sine[1,2]Phase, $(P)$(R)[X,Y]Sine[1,2]Phase_RBV  ao, ai 
Simulation Modes¶
Linear Ramp¶
For monochrome images (NDColorMode
= NDColorModeMono
) the simulation
driver initially sets the image[i, j] = i * SimGainX + j * SimGainY *
ADGain * ADAcquireTime * 1000
. Thus the image is a linear ramp in the
X and Y directions, with the gains in each direction being detector
specific parameters. Each subsquent acquisition increments each pixel
value by ADGain * ADAcquireTime * 1000
. Thus if ADGain
= 1 and
ADAcquireTime
= .001 second then the pixels are incremented by 1. If the
array is an unsigned 8 or 16 bit integer then the pixels will overflow
and wrap around to 0 after some period of time. This gives the
appearance of bands that appear to move with time. The slope of the
bands and their periodicity can be adjusted by changing the gains and
acquire times.
For color images (NDColorMode
= NDColorModeRGB1/RGB2/RGB3
) there are
3 images computed, one each for the red, green and blue channels. Each
image is computed with the same algorithm as for the monochrome case,
except each is multiplied by its appropriate gain factor (SimGainRed
,
SimGainGreen
, SimGainBlue
). Thus if each of these color gains is 1.0
the color image will be identical to the monochrome image, but if the
color gains are different from each other then image will have color
bands.
Array of Peaks¶
For monochrome images, an array of gaussian peaks is produced. The
user specifies the start location for the first peak in PeakStartX
&
PeakStartY
. The size of the peak is controlled by PeakWidthX
and
PeakWidthY
. The array is specified by giving the number of peaks in
each direction with PeakNumX
and PeakNumY
and the step size between
peak centroids with PeakStepX
and PeakStepY
. The amplitude of each
peak is controlled by SimGainX
, SimGainY
, and ADGain
. If
SimGainX
= 1, SimGainY
= 1, SimNoise
= 0, and
SimPeakHeightVariation
= 0 then the peak height is equal to ADGain
,
ADGain
= 255 would be appropriate for an 8bit image. Note that data for
each peak is only added to the image over a range of four times the
PeakWidth
in any direction (in the interest of speed).
Dynamic behavior can be introduced into the system by changing
PeakVariation
and Noise
records. PeakVariation
introduces variation
in the height of each peak in the array and Noise introduces variation in
each pixel.
The description for RGB images is the same as for the Linear Ramp. Pixels are computed the same way as for monochrome and there is a separate gain for each color.
Sine¶
The image is constructed from 2 sine waves in the X direction and 2 sine waves in the Y direction. The amplitude, frequency, and phase of each of the 4 sine waves can be controlled. The two sine waves in each direction can be combined either by addition or by multiplication. There also global offset and noise parameters. Each sine wave is constructed using the following equation:
X/YSine[i] = Amplitude * sin((Count[X,Y] * Gain[X,Y] / Size[X,Y] * Frequency + Phase/360) * 2 * PI)
where
Count[X,Y]
is an integer counter that increments by 1 for each element of the sine wave for each new image. It reset to 0 when the image is reset with SimResetImage, or when the image dimensions or datatype are changed.Amplitude
sets the sinewave amplitude. The peaktopeak value is twice this.i
is an index that goes from 0 to the image dimension SizeX or SizeY.Gain[X,Y]
isGainX
orGainY
defined above.Size[X,Y]
isSizeX
orSizeY
, the number of pixels in the X or Y direction.Frequency
is the sine wave frequency.Frequency
= 1 is one full period across the image.Phase
is the phase angle in degrees.
There are 4 separate values for Amplitude, Gain, and Frequency, one for each of the 4 sine waves.
If the Frequency is an integer then there will be an integer number of sine wave periods across the image, and these will appear to be stationary from one image to the next. If Frequency is not an integer then there will be a noninteger number of periods across the image, and the sine wave will appear to move from one image to the next. This is because Count[X,Y] is not reset to 0 for each new image.
In monochrome mode the following equation is used to construct each image:
Value[i,j] = Gain * (Offset + (Noise * random) + XSine1[i] (+ or *) XSine2[i] + YSine1[j] (+ or *) YSine2[j])
where
Gain
is the overall image gain defined inADBase.template
.Noise
is the overall noise level in the image.random
is a random number in the range 1 to 1 that is different for each pixel in the image.i
is an index that goes from 0 to the image dimension SizeX.j
is an index that goes from 0 to the image dimension SizeY.XSine1
,XSine1
,YSine1
,YSine2
are the 4 sine waves described above.(+ or )
is either addition or multiplication depending on the value ofXSineOperation
andYSineOperation
described above.
In color mode (NDColorMode
= NDColorModeRGB1/RGB2/RGB3
) the
following equations are used to construct each image:
Red[i,j] = Gain * GainRed * (Offset + (Noise * random) + XSine1[i])
Green[i,j] = Gain * GainGreen * (Offset + (Noise * random) + YSine1[j]
Blue[i,j] = Gain * GainBlue * (Offset + (Noise * random) + (XSine2[i] + YSine2[j]) / 2))
where the values have the same meaning as for monochrome images, and
GainRed
, GainGreen
, and GainBlue
are the same as for Linear Ramp
mode explained above. Note that the red image is a single sine wave in the
X direction (XSine1
), the green image is a single sine wave in the Y
direction (YSine1
), and the blue image is the sum of XSine2
and
YSine2
.
Unsupported standard driver parameters¶
 Collect: Number of exposures per image (ADNumExposures)
 Collect: Trigger mode (ADTriggerMode)
 File control: No file I/O is supported
Configuration¶
The simDetector driver is created with the simDetectorConfig command, either from C/C++ or from the EPICS IOC shell:
int simDetectorConfig(const char *portName,
int maxSizeX, int maxSizeY, int dataType,
int maxBuffers, size_t maxMemory,
int priority, int stackSize)
The simDetectorspecific fields in this command are:
maxSizeX
Maximum number of pixels in the X direction for the simulated detector.maxSizeY
Maximum number of pixels in the Y direction for the simulated detector.dataType
Initial data type of the detector data. These are the enum values forNDDataType_t
, i.e. 0: NDInt8
 1: NDUInt8
 2: NDInt16
 3: NDUInt16
 4: NDInt32
 5: NDUInt32
 6: NDFloat32
 7: NDFloat64
For details on the meaning of the other parameters to this function refer to the detailed documentation on the simDetectorConfig function in the simDetector.cpp and in the documentation for the constructor for the simDetector class.
Example st.cmd startup file¶
There an example IOC boot directory and startup script provided with areaDetector: Example st.cmd Startup File.
Screenshots¶
Linear Ramp Mode¶
The following is an IDL epics_ad_display screen using image_display to display the simulation detector in monochrome linear ramp mode.
IDL epics_ad_display.pro display of simulation detector in monochrome
Ramp Mode¶
The following is an ImageJ plugin EPICS_AD_Viewer screen displaying the simulation detector in color linear ramp mode.
ImageJ EPICS_AD_Viewer display of simulation detector in color linear
Simulation setup screen with Peaks mode selected¶
This is an example of the MEDM screen that provides access to the specific parameters for the simulation detector. In this case Peaks mode is selected.
Simulation setup screen with simple Sine mode setup¶
This is a simple example of Sine mode. The XSine1
frequency is 2 and
the YSine1
frequency is 4. The Sine2
amplitudes are zero, so there is
a single sine wave in each direction.
ImageJ display with the above simple Sine mode parameters¶
This is a complex example of Sine mode. There are 2 sine waves in each direction, with multiplication in X and addition in Y.
Simulation setup screen with Sine mode parameters in RGB1 color mode¶
This is a example of Sine mode in RGB1 color mode.
 The red signal is controlled by a horizontal sine wave with a frequency of 2 and a phase of 90 degrees.
 The green signal is controlled by a vertical sine wave with a frequency of 4 and a phase of 45 degrees.
 The blue signal is controlled by the sum of sine waves in the horizontal with a frequency of 5 and in the vertical with a frequency of 20.