| Thermal drying by hot-air is a widely used way to dry fruits and vegetables in practice. In this paper, Red fushi apple was the object in the research. Aiming at several questions in the study of numerical simulation of the drying process of fruit and vegetable, several theories and methods were investigated and developed. We finished some works as following:1)After reviewing the historical development of drying mathematical model at home and abroad, the shortcoming of ignoring boundary' s shrinkage or little taking it into account was universally found in models, so new equations were investigated to describe the phenomenon. Basing on analysis of dimension, the relationship between the shrinking rate of the volume of a piece of fruit and its water content was obtained through experimentation. Then this relationship was applied to each interior elementary particle of fruit. Sequentially "The universal formula" thinking over the shrinkage in the diameter' s direction and "The spheriform formula" thinking over the shrinkage of a three-dimensional sphere were established. We designed a calculated experiment to validate the effect of these formulas, the experimental results showed that "The spheriform formula" was better than "The universal formula" to forecast the experiment data.2)The study of the quality of fruit and vegetable in store, traffic and process is found on the character of interior water. In studying the drying process by numerical simulation, the computational results of moisture must be validated by experiment. However, traditional methods to obtain the data of moisture run short of ability of Non-destructive evaluation, the computational value was only validated by the value of average moisture in the fruit, and was not confirmed by the distribution value of the moisture. To test the distribution of water in fruits, through experiment and analysis of the experiment result, the relations of different point moisture in fruit with the corresponding CT value on the CT image and the RGB value on the image with the corresponding CT value were found. The marked linear relativitiesbetween a point moisture of fruit and its CT value, between CT value on a image and its RGB value both were existed. So every point moisture in a fruit can be found though the CT value or the RGB value at this point. It is a new way to test the moisture of different points in fruit.3)CT image is a kind of aggregation that containing a lot of information. In this paper, a review of the current study of image processing for detecting fruits and vegetables was introduced, and some methods and applications were summarized too, then we applied the technology of image processing to analyze CT images. At First image preprocessing was done, it include: providing tools by which you can select different zones on a CT image, image format converting from a 24 bits color image to a 8 bits gray image and image enhancement with medium value filter, then a method for recognizing different object at the same time had been put forward, by which objects were separated from background and identified. In practice, the method was proved with universal application and good noise reduction. Two methods used to obtain the borderline, contour tracing and erosion algorithm, were studied.4)At the aspect of information visualization, the method of pseudo-color processing was used to enhance the effect of distinguishing details among similar colors, thereby different particulars on a image could be easily discovered, and in the status bar of the image processing system the accurate information (Gray scale value, CT value and water content) of the point the mouse stay was displayed in real time. At the aspect of statistical analysis, after object recognized, the statistical information of each identified object was computed out and showed synchronously. For example: the percentage of area in which the value of water content at any point is not large than a prescribed value was calculated.In this paper, new ways and methods had been brought fo... |
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