The present invention relates to an image file storing and retrieving method and apparatus and, more particularly, to an image storing and retrieving method suitably adapted to an image information storing and retrieving apparatus for retrieving images by use of layout information about document images.
Recently introduced image filing devices are being progressively introduced into automated offices following the introduction of the word processor, personal computer and facsimile machine. The filing device is attracting much attention for its potential for promoting paperless work in clerical and design offices. The image filing apparatus is capable of storing large amounts of image information on optical disks from which necessary information is instantaneously retrieved and printed out. This feature makes the apparatus particularly attractive to--and purchased by--those departments that handle huge quantities of documents. A big challenge for the image filing apparatus is how to efficiently retrieve any desired document from the massive storage inside.
One way to implement effective document retrieval is to use keywords. This method involves adding a keyword to each image, the keyword representing the contents of each image when the data of that image is stored. Later, a desired image is retrieved using the corresponding keyword. Generally, a keyword to be added to an image is an important word that represents the concept of that image. One disadvantage of this method is that because keywords are linguistic by definition, they cannot fully represent pattern characteristics intrinsic to images.
One solution to the above problem is the apparatus disclosed in Japanese Patent Laid-open No. 60-83179. This prior art apparatus achieves image retrieval in accordance with human intuition using line drawings of original images in place of keywords and works as follows. An image to be stored is first read by an input device, the read image being shown on a display unit. The contour of the displayed image is traced manually using a pointing device (e.g., mouse, tablet, etc.). The traced figure is contracted and used as the equivalent of a keyword. Because each contracted figure represents only the extracted characteristic of the corresponding image, it is easy-to distinguish the desired image from other images. And because the traced contours are contracted, a large number of "keywords" may be collectively displayed on the display screen. When one of the contracted figures on the display screen is designated with the pointing device, the corresponding image is read from optical disk for output.
As described, the prior art apparatus defines line drawings or figures as keywords. This allows the operator to use conceptual patterns conforming to his or her intuition as virtual keywords representing images. Thus any desired image is retrieved with relative ease from optical disk storage of large capacity. The devices associated with the above prior art apparatus are also disclosed in Japanese Patent Laid-open Nos. 60-19275, 62-72067 and 62-93757.
The prior art apparatus, as described, allows a line drawing to be extracted upon image entry, the extracted drawing or figure being used as a virtual keyword. Unlike linguistic keywords, these line drawing "keywords" provide image retrieval more in accordance with human intuition.
One disadvantage of the above described prior art is that it takes huge amounts of time to trace manually the contour of each and every image in order to create the corresponding "keyword".
Another disadvantage is that there are collectively displayed all stored line drawing patterns to choose from and the greater number of images stored, the greater amount of time is required to select a desired pattern from the increasingly numerous patterns representing the stored images.
A further disadvantage of the prior art is that because one stored line drawing pattern corresponds only to one original image, other images similar to one selected image cannot be retrieved without selecting the patterns specifically corresponding thereto.