Detection and Measuring of Translucent Liquid Volumes in Microtiter Plates

The task of measuring dispensed liquid volumes in microtiter plates commonly used for large test series of serums with volumes smaller than 50 µl has not been solved satisfactorily. Several methods to measure the volume before dropping into the micro-testtubes do exist. But for a reliable determination that a drop has really been pipetted and to measure it no method is known. The developed solution bases on scene structuring and image processing. This solution allows to measure the dropped liquid volume directly in the microtest-tubes, even if the microtiter plates are moving. The method uses specially generated structured image backgrounds and the optical properties of the liquid itself. A camera of appropriate size and parameters snaps a digital image of the micro test tube and transfers this image to the computer. Because the generated background structure is known and the optical properties of the liquid drop destroys this structure, the location and the borders of the drop can be determined using developed image processing procedures. Knowing the location of the drop, the area covered in the micro test tube and the physico-chemical properties the volume can be calculated with the desired precision. Different background structures can be used.