Introduction

Calibration and processing for Aurox Clarity microscopy data.

This package provides two Python modules for Aurox Clarity instruments -- one for control and another for processing of image data.

Installation

The package can be installed or uninstalled using pip, the standard Python package manager:

python -m pip install /path/to/clarity_processor/directory
python -m pip uninstall aurox_clarity

Description

Controller

The controller module uses a Python wrapper around the hidapi library to access devices on the serial bus. Communication can be accomplished via the sendCommand() method and the module provides definitions for all commands and parameters of the protocol:

Command	Input/Output
GETONOFF	1 byte; SLEEP or RUN
SETONOFF	1 byte; SLEEP or RUN
GETDOOR	1 byte; DOORCLSD or DOOROPEN
GETDISK	1 byte; DSKPOS0 or DSKPOS1 or DSKPOS2 or DSKPOS3 or DSKERR or DSKMID
SETDISK	1 byte; DSKPOS0 or DSKPOS1 or DSKPOS2 or DSKPOS3
GETFILT	1 byte; FLTPOS0 or FLTPOS1 or FLTPOS2 or FLTPOS3 or FLTERR or FLTMID
SETFILT	1 byte; FLTPOS0 or FLTPOS1 or FLTPOS2 or FLTPOS3
GETCAL	1 byte; CALON or CALOFF
SETCAL	1 byte; CALON or CALOFF
GETVERIOSN	3 bytes; version in the format byte1.byte2.byte3
GETSERIAL	4 bytes; BCD serial number (little endian)
FULLSTAT	8 bytes; 3 bytes for the version and 1 byte for each of on/off status, door status, disk position, filter turret position, and calibration light status

All commands sent to a Clarity device could also get a response of CMDERROR when the command could not be interpreted. As an alternative to sending command directly, methods are provided for each command:

• switchOn
• switchOff
• getOnOff
• setDiskPosition
• getDiskPosition
• setFilterPosition
• getFilterPosition
• setCalibrationLED
• getCalibrationLED
• getDoor
• getSerialNumber
• getFullStat

Usage:

import aurox_clarity.controller

ctrl = aurox_clarity.controller.Controller()

ctrl.switchOn()

# Set the filter wheel to the 3rd position
ctrl.sendCommand(aurox_clarity.controller.SETFILT, aurox_clarity.controller.FLTPOS3)

# Set the disk slide to 2nd position
ctrl.setDiskPosition(aurox_clarity.controller.DSKPOS2)

if ctrl.getDoor() == aurox_clarity.controller.DOOROPEN:
    print("The filter turret door is open!")

serial = ctrl.getSerialNumber()

version, onoff_state, door_state, disk_pos, filt_pos, cal_state = ctrl.getFullStat()

# Turn off and close
ctrl.switchOff()
ctrl.close()

Processor

The processor module uses OpenCV to process images that have been acquired with a camera connected to an Aurox Clarity instrument. Before confocal images can be computed, the system needs to be calibrated first. For this the calibration LED needs to be turned on with the controller module. This will project a calibration pattern on the camera. An image of this pattern is used for the initialisation of the Processor class. You should set up a instance of the class for each filter/disk position combination that you use as the calibration can be different.

The class provides several methods that differ in their inputs and algorithms:

• process(): takes 1 combined Numpy array, converts it to a cv2.UMat, and then performs scaled subtraction.
• process_gpu1(): takes 2 cv2.UMat images and performs scaled addition
• process_gpu2(): takes 1 combined Numpy array, converts it to two cv2.UMat images, and then performs scaled subtraction
• process_gpu3(): takes 1 combined Numpy array, converts it to two cv2.UMat images, and then performs scaled addition
• process_cpu(): takes 1 combined Numpy array and performs scaled subtraction
• process_cpu1(): takes 1 combined Numpy array and performs scaled addition

The performance of these different methods can be benchmarked with the opencv_test module in the tests directory. On a macbook pro with i7 processor at 2.2GHz and Intel Iris Pro graphics, the calibration calculation takes 1.2 secs (this only needs to be done at initialisation) and then processing individual images takes about 7.5ms. We have some evidence that this final processing step is quicker in C++ (~1ms) so ultimately it might be worth rewriting the processing step using the opencv C++ library directly. Some other processing methods have been added that show a significant (~3x) speed-up on this. Basically this is all depends on how the data to be processed is converted to the opencv UMat class for processing. The UMat class encompases data that is stored in GPU memory and will be processed using OPENCL. Different routines might see different speed-up depending on the hardware used.

Usage:

import aurox_clarity.controller
import aurox_clarity.processor

ctrl = aurox_clarity.controller.Controller()
ctrl.switchOn()
ctrl.setCalibrationLED(aurox_clarity.controller.CALON)

# Take an image with the camera (not covered by this package)
calib_img = take_image()

proc = aurox_clarity.processor.Processor(calib_img)
# Calibration is successful in the absence of exceptions

ctrl.setCalibrationLED(aurox_clarity.controller.CALOFF)

img = take_image()

confocal_img = proc.process(img)