System and method for monitoring birefringent particles in a fluid
An imaging system with an imaging mechanism which includes polarization analyzers, which may be crossed polarization analyzers, positioned to provide birefringence images of particles in the fluid passing through the flow chamber. Captured images are of high resolution and may be used in comparison to known images of a library of images. The system and related method enhance the accuracy and sensitivity of particle monitoring by utilizing birefringence imaging combined with particle analysis and the detection of each particle's characteristic features, such as crystalline features. The system includes a scatter detector used to trigger backlighting of the flow chamber and capture images of particles therein.
1. A system for imaging birefringent particles in a flowing fluid, the system comprising:
a. a flow chamber including a channel arranged to transport the flowing fluid therethrough at a selectable rate;
b. a light source arranged to generate scatter excitation light to illuminate birefringent particles in the flowing fluid in the flow chamber;
c. a backlighting generator arranged to produce a light of sufficient intensity to backlight the flow chamber, wherein the backlighting generator includes two light emitting diodes;
d. a microscope objective arranged to focus light from the light source onto the flow chamber;
e. a scatter detector to detect changes in the light from the light source indicative of the existence of one or more particles in the flow chamber;
f. control electronics configured to receive signals from the scatter detector, wherein the control electronics are coupled to the backlighting generator and configured to activate the operation of the backlighting generator;
g. an image capturing system including one or more cameras to capture images of the birefringent particles in the flowing fluid, a first polarization analyzer and a second polarization analyzer, wherein the first polarization analyzer and the second polarization analyzer are arranged in a cross polarization configuration to permit the passage of light to the one or more cameras only when the birefringent particles with detectable birefringence pass between the first polarization analyzer and the second polarization analyzer; and
h. a computing device to receive signals from the control electronics and the image capturing system and to output information about the birefringent particles detected in the flowing fluid.
2. The system of claim 1 wherein the first polarization analyzer and the second polarization analyzer of the image capturing system are arranged with their axes perpendicular to one another.
3. The system of claim 1 wherein the one or more cameras include a digital or analog camera and a framegrabber.
4. The system of claim 1 wherein the light source is a laser with an excitation filter.
5. The system of claim 1 wherein the computing device includes a database to store data and images associated with detected particles and software to generate with the computing device particle data as image collages and interactive scattergrams.
6. The system of claim 1 wherein the image capturing system includes two cameras.
7. A method for imaging birefringent particles in a flowing fluid, the system comprising:
a. transporting the flowing fluid through a channel of a flow chamber at a selectable rate;
b. generating scatter excitation light to illuminate the flowing fluid in the flow chamber;
c. detecting scattered light signals indicative of the existence of one or more birefringent particles in the flow chamber;
d. backlighting the flow chamber upon detection of scattered light signals using two light emitting diodes;
e. cross polarizing light from the backlighting of the flow chamber with a first polarization analyzer and a second polarization analyzer to permit only light passing through birefringent particles to pass to one or more cameras to capture images; and
f. outputting information about the birefringent particles detected in the flowing fluid based on captured images thereof.
8. The method of claim 7 wherein the step of cross polarizing light includes placing the first polarization analyzer and the second polarization analyzer with their polarization axes perpendicular to one another in relation to the flow chamber so that light passes to the one or more cameras only when the birefringent particles pass between the first polarization analyzer and the second polarization analyzer.
9. The method of claim 7 wherein the one or more cameras include a digital or analog camera and a framegrabber.
10. The method of claim 7 wherein the step of generating scatter excitation light is achieved with a laser and an excitation filter.
11. The method of claim 7 wherein two cameras are used to capture images.
12. The method of claim 7 further comprising the steps of storing data and images associated with detected particles and generating particle data as image collages and interactive scattergrams.