Topographic Map Midline Object Recognition And Reconstruction

As an important branch of computer technology ,the computer graphic technology developed veiy fast in these years.The whole world was presented an entirely new apperance by the computer graphic technology,such as Computer aided design(CAD),computer graphic(CG) and computer imagine processing(CIP).But with the extension of CAD and the in-depth research of?CG and CIIP,a new problem was brought forward,which was how to convert two value image into vectorgraph to meet the need of CAD.Lots of studies had been done on it,but up to now,the problem was far from being solved. On the basis of in-depth study,this paper put forward a complete set of computer image recognition and rebiulding methods which primarily concludes truncation track recognition method of line object recognition and region growing method of line width recognition through which computer can recognise the line object(including polygon,polyline and ellipse) on the black & white raster image. Truncation track recognition method of black and white raster image .Using this method ,computer start from a origional point on the line ,search for the next point of the line with a corresponding truncation radius ,till recognise the whole object .Test shows that the method recognise object quickly and correctly. Region growing method of line width recognition.According to the method,a square of one pixel starts from a point of a line grows on the necessary directions,then form the minimum rectangle region which can cover the whole line on the width,and recognise the line width according to the relationship between the amount of black pixels in the rectangle region and the line width.The paper also gives the nicety rate of the method.