Microscope Light Dimmer for Biomedical Image Enhancement with Virtual Instrumentation
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I. INTRODUCTION
Light dimming is based on adjusting the voltage
which gets to the lamp. Light dimming has been
possible for many decades by using adjustable power
resistors and adjustable transformers. The problem of
those light controlling methods have been that they
are big, expensive, have poor efficiency and they are
hard to control from remote location.


II. DESIGN OF LIGHT REGULATION
On the basis of simulations was designed wiring
dimmer (Fig. 1). The power supply is made directly
from the mains supply 230V via input transformer [1].
Dimming feature is provided through one PWM
channel, which generates pulses at gate on switching
transistor [2].


III. VIRTUAL INSTRUMENTATION IN
LABVIEW
Virtual instrument is software analogy of real
meter with all functions. Using universal measuring
PC card we can simulate big number of expensive
meters. User can freely modify design, controls and
indicators of virtual meter; virtual instrument is
characterized with high degree of flexibility. One of
development systems for virtual instrumentation is
National Instruments LabVIEW.


IV. VIDEOSEQUENCE ACQUISITION
Solution of actual case of image analysis can be
splitted into few basic steps: image (video)
acquisition, image preprocessing and image
PROCESS

Hardware acquisition equipment is: inverse
biological light microscope and high speed
monochrome camera connected to PC through IEEE
1394 (FireWire). LabVIEW application is software
platform for videosequence acquisition. Acquisition
system and camera connection with microscope is in
Fig. 6 and Fig. 7.


IV. VIDEOSEQUENCE PREPROCESSING
Preprocessing has two goals: to shorten analysis
time and improve kinetic parameters analysis.
Time needed for analysis can be reduced by
cutting off of the regions or frames (redundant time
intervals) which don’t contain relevant information
[7]. In this aspect we can talk about time reduction or
spatial reduction (selection of ROI containing isolated
cell). Script is very simple and output is time or
spatial (or both) reduced videosequence.


V. CONCLUSION
Due to fast digital camera, system contains
intelligent illumination dimming hardware
automatically regulated through measurement card.
Regulating parameter for dimmer (PWM duty cycle)
is computed from image features, histogram
distribution and intensity relations. Dimming helps
system to preserve optimal acquisition light
conditions for accurate image/sequence processing
and eliminates abnormal heat generation in
microscope condenser when using high-power lamp.
This system can be used in sophisticated
measurements in many educational, research and
industrial applications where moving objects of
investigation can’t be equipped with sensors of
kinematics parameters.