1. Field of the Invention
This invention relates to an image data filing system which reads an original drawing such as a map or the like by an image scanner and manages it as image data.
2. Description of the Prior Art
FIG. 1 is an explanatory view showing a first conventional image data filing system, in which reference numeral 1 designates a map as an original drawing to be input; 2, an image scanner for reading the map 1 and converting it into digital image data; 3, image data output from the image scanner 2; 4, a record file such as an optical disc or the like for storing the image data 3; 5, a display image data read from the record file for display; and 6, a display device such as a CRT display for displaying the display image data 5.
Next, the operation of this system will be described. In the case where the map is subjected to filing management as image data, the map 1 as the original drawing is first read by the image scanner 2 and converted into the digital image data 3. The image data 3 converted by the image scanner 2 in this manner is fed to the record file 4, where it is written and stored into a predetermined record area. When the need occurs for the stored image data 3 to be displayed on the display device 6, this is fed as the display image data 5 read from the record area of the record file 4 to the display device 6 to be displayed thereon.
Since the first conventional image data filing system is constructed as described above, the image data 3 is subjected to read/write processing in units of the original drawing as an input, and this poses a problem of difficulty in portraying a continuous display of plural adjacent originals, more particularly, a unity-scale continuous display of plural adjacent originals having different original scale factors, which still remains especially in case of a map or the like.
FIG. 2 is an explanatory view showing a conventional second image data filing system, which is the same as the structure shown in FIG. 1 except that the display image data 5 in the first conventional image filing system shown in FIG. 1 is replaced by a read image data 5a of an original scale read from the record file 4 and a reduced display image data 5b whereto said read image data is reduced. Parts in FIG. 2 which are the same or correspond to those shown in FIG. 1 are indicated by the same reference numeral as used in FIG. 1, the detailed description of which is omitted.
The operation will be described hereinafter. For example, in the case where the drawing as an image data is subjected to filing management, the drawing 1 as the original drawing is first read by the image scanner 2 and converted into the original size digital image data 3 on the scale of 1/1. The original size image data 3 read by the image scanner 2 in a manner as described is fed to the record file 4, where it is written and stored into a predetermined record area. When the need occurs for the stored image data 3 to be displayed on the display means 6 on the scale of 1/5, the read image data 5 on the scale of 1/1 is first read from the record area of the record file 4, and is subjected to reduction processing to generate a reduced display image data 5b on the scale of 1/5, which is sent to the display means 6 for display.
Since the second conventional image data filing system is constructed as described above, the image data is stored only as the original size image data 3 on the scale of 1/1 in the record file 4. In the case where the need occurs for a reduced drawing (an enlarged drawing) to be displayed on the display means 6, the read image data 5 on the scale of 1/1 read from the record file 4 need to be subjected to reduction (enlargement) processing every time to a reduced (enlarged) scale to be displayed, posing a problem that a considerably long processing time is required before the data is displayed on the display means.