Multi-Exposure Speckle Imaging (MESI) is a method that obtains speckle images at different exposure durations and has the capability to predict the relative flow rate in the presence of static scatters and the camera noise. The MESI technique has been performed in relatively small vessels (80μm–300μm) before, such as the cerebrum, the retina and the skin. Here we firstly, to the best of our knowledge, detected the flow rate in a 2 mm2 –cross-section vessel using the MESI method, whose size medically mimicked the artery coronary. The phantom experiment was conducted to measure the flow rate ranging from 1 mm/sec to 10 mm/sec and the linear response of the velocity measurements was determined. In addition, the coherent parameter β was separately computed by MESI and the laser speckle contrast imaging (LSCI) method. It turned out the coherent parameter β obtained by the former model was more accurate with taking the static noise into account. The experimental results found that the MESI technology is promising to be applied in the biomedical measurement of the blood flow in the coronary artery bypass grafting.
This article studies two main ways of gamut expansion: improving the color purity of the primary color and increasing the number of primary colors. A program for the gamut coverage of the multi- primary color display system is written. The color coordinates of the laser TV developed by ourselves are measured and the actual value of color gamut is calculated. The test data verifies the simulation result.
Self-developed three- primary color laser projection TV based on RGB (RED, GREEN, BLUE) laser diode is given by this paper. Laser diode has very narrow line-width, high color purity and saturation, and displays more colorful and gorgeous image. In this work, the Helmholtz-Kohlrausch effect is applied for studying the enhanced perceived brightness of the RGB laser projection television. The experiments are designed for the difference perceived brightness between the RGB laser projector TV and the Blue laser- excited phosphor laser projection TV. The ratio of the enhanced perceived brightness of RGB laser projector TV is evaluated.
In this paper, we design a setting that could constantly monitor the screen vibration frequency and a speckle measurement system that simulates characteristics of human eye to record speckle images. Three vibrating methods, including acoustic wave vibration, frame vibration and chip motor vibration, are adopted to eliminate speckle. Speckle contrast, power consumption and noise are measured, separately. On our experimental platform, when the speckle contrast is less than 5%, the human eyes perceive free of speckle. By comparison, the chip motor vibration has optimal performance that the speckle contrast is 4.97%, power consumption is 1.51 W, and noise is 43.1 dBA. Therefore, the chip motor vibration method is the most suitable method for improving image quality in laser display.
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