Studies On Volume Measurement Of Nostoc Flagelliforme With Computer Vision

China is one of the most serious desertification counties in the world. It's extremely important to effectively control the spread of desertification. Nostoc flagelliforme, which grows in desert or semi-desertification environment, is a kind of terrestrial nitrogen-fixing cyan bacteria. It can improve the physical and chemical qualities of soil by providing carbon and nitrogen for the growth of microorganism. In this thesis, the volume measurement of nostoc flagelliforme with computer vision is studied, which grows on a solid base. It is hoped to achieve the dynamic observation of the growth of nostoc flagelliforme and to provide effective experiment data for improving the physical and chemical properties of soil for solving desertification.Binocular stereo vision is a non-contact measurement technology, which has many advantages, such as flexible, simple, and high measurement accuracy. As being easy to achieve on-line and non-contact measurement, it has been widely used in different areas, and can meet the demands of measuring the volume of nostoc flagelliforme. Therefore, binocular stereo vision is adapted in this thesis.After analyzing the measurement principles of binocular stereo vision, a projected light line is added to fast the calculation of matching two images taken by different cameras. The mathematic model of binocular stereo vision is used to calibrate the measuring system, to measure the volume of nostoc flagelliforme.In system structure design, two step motors are employed to move and rotate the nostoc flagelliforme being measured, and to correctly scan its whole area. Serial port communication is used to implement the communication between a PC and a micro-controller unit to control the two step motors. In software design, multi-threaded programming technique is used to acquire images. A gravity method is used to extract the center of projected light line. The matching of images taken by different cameras is achieved by using epipolar constraint and the projected light line. Finally, measurement experiments are conducted with satisfied results. The feasibility and effectivity of the measurement method proposed in this thesis are verified, which can be used to measure the growth volume of nostoc flagelliforme.