| The present clinical bio-particle(such as blood cell and urine sediment) measurement techniques are not base on morphology of the particles, but the electric resistance or light scattering. The ideal technique or technology should observe the shape and pattern of numerous bio-particles one by one swiftly, with the help of other parameters, to recognize, classify, count the number, and measure the physical parameters and biochemical contents. This dissertation conceived an Imaging Flow Cytometry (I-FCM) technique. The diluted bio-sample with its bio-particles contained are sprayed out from a nozzle, then the bio-particles are photographed by a digital camera one by one. The photos are developed with image processing software, allowing the morphology of bio-particles to be studied.Theoretically, this technique has the advantages of high accuracy, high speed, traceability, and self-learning ability.For testing I-FCM, a prototype is designed and built. The flow velocity measuring system works on double light-scattering. When a particle passes through two light beams where the distance is known, two scattering light pulses are detected by a photodiode. The regulation of sheath flow velocity is approached by feedback from the flow velocity and adjusting the air pressure in the sheath liquid reservoir. Experiment shows, the sheath flow velocity can be stabilized within 5%. The photographic system includes a strobe light, a microscope which has 10mm observation distance and 20μm depth of focus and a fast CCD camera whose fastest shutter is 16μs. White blood cells (WBC), urine cast and crystal are captured successfully by this prototype. The shapes and patterns of the bio-particles were recognizable.The digital image process for WBC is studied. Wavelet transformation combined with the point wise variance method is applied to de-noise the WBC pictures, and OSTU2 in the HSV color space for separating images, a satisfactory feature selection method for extracting image features, support vector machine(SVM) for vector classification are applied. The primary experiment through 246 WBC images indicates that, the precision is 84.5% and 78% for neutrophile and lymphocyte respectively.This dissertation reviewed all the existing liquid level detection(LLD) techniques. The technical maturity of the most popular capacitive LLD is calculated with TRIZ; the conclusion is that the capacitive LLD is at its evolution stage of between maturity and decline. The evolution direction of LLD is made as well.A novel LLD technique based on light reflection is designed. A laser generator and a position sensitive detector (PSD) are placed at the upper-right and upper-left of a sample tube respectively. The laser, emitting from the laser generator, illuminates the surface of liquid sample, then reflects from the surface to the PSD. The position of the light spot on the PSD has a linear relationship with liquid level. Experiment shows that the measurement accuracy could reach to 0.27mm.Another level detection based on image process is discussed. It takes photo of the inner wall of sample tube, and measures the distance from the tube's top to the boundary of the liquid surface on the tube's inner wall. It can measure the level non-contactably, and is not influenced by the conductivity of detected liquid. Also it can detect if the tube cap is off and if there are bubbles on the liquid surface.A compensation technique for photographing a fast moving object with a slower camera is discussed. A mirror is placed beside the surface of the shooting area at a 45 degree angle toward the direction of the moving object. A mirror moves along with the object at the same speed. CCD camera focuses on the mirror, takes a photo of the object's image in the mirror. A simulation shows that with the help of this compensation technique, the same camera can take clear photos of a 10 times faster moving object.
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