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Claims  |
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What is claimed is:
1. In an image filing system including image input process means for
inputting image data representing an image to be processed, store means
for storing the image data input by said input process means, retrieval
means for retrieving image data stored in said store means, and a display
having a predetermined display dot number for displaying image data
retrieved by said retrieval means, a method of filing images data
comprising the steps of:
dividing image data representing an input image having a dot number larger
than said predetermined display dot number into a plurality of partial
images, representing in combination the entirety of said input image, at a
fundamental unit equal to said predetermined display dot number;
producing compressed data by compressing each of the divided partial
images;
predetermining position information of a distinguishable partial image
among all of the divided partial images; and
storing said position information together with said compressed data of
said divided partial images into said store means.
2. An image filing method according to claim 1, further comprising:
an image retrieval step of reading out image data relating only to said
distinguishable partial images from said store means, while referring to
said position information stored in said store means or said input process
means through said retrieval means, and for expanding said read image data
so as to be displayed on said display means.
3. An image filing method according to claim 2, wherein said image
retrieval step includes:
a step of outputting all of partial images constituting an image
corresponding to the distinguishable partial image designated from the
distinguishable partial images displayed on said display means.
4. An image filing method according to claim 1, wherein a selection is made
to only one distinguishable partial image with respect to the respective
input images.
5. An image filing method according to claim 1, further comprising:
a step of determining a complexity degree of the partial image
representative of a changing point number of pixels per a unit area with
respect to each of the partial images of the input image, and for
identifying said partial image of each input image based upon said
determining step.
6. An image filing method according to claim 1, further comprising:
a step of determining a partial image in which specific information is
present, as the distinguishable partial image.
7. In an image filing system including image input process means for
inputting image data representing an original image to be filed, store
means for storing the image data input by said input process means,
retrieval means for retrieving image data stored in said store means, a
display having a predetermined display dot number for displaying image
data retrieved by said retrieval means, a method of filing image data
comprising the steps of:
dividing image data representing an input image having a dot number larger
than said predetermined display dot number into a plurality of partial
images, representing in combination the entirety of said input image, at a
fundamental unit equal to said predetermined display dot number;
producing compressed data by comprising each of the divided partial images;
determining a distinguishable partial image from among the divided partial
images; and
storing the compressed data representing said determined distinguishable
partial image into a specific store region of said store means and storing
the compressed data of the remaining partial images into other store
regions of said store means.
8. An image filing method according to claim 7, further comprising:
a retrieval step of expanding only the image data stored in said specific
store region of the store means in response to a retrieval instruction so
as to successively display the distinguishable partial images.
9. An image filing method according to claim 7, wherein said store means
stores the partial images with respect to the respective images in such a
manner that each of the partial images is allocated at a page unit, and
allocates at least a head page of said distinguishable partial image as a
specific store region.
10. An image filing method according to claim 9, wherein a plurality of
said distinguishable partial images are provided with each of the images,
and are sequentially allocated from said head page in accordance with a
priority order.
11. An image filing retrieving system comprising:
an image data input device;
store means for storing image data representing an input image inputted by
said input device;
retrieval means for retrieving the image data stored in said store means;
a display having a predetermined display dot number for displaying
retrieved image data;
process means for performing a filing process on the input image data, said
process means including means for dividing input image data having a
display dot number larger than said predetermined display dot number into
partial images, representing in combination the entirety of said input
image, at a fundamental unit corresponding to said predetermined dot
number, means for compressing said partial images so as to output
compressed data, means for extracting position information of a
distinguishable partial image from the respective divided partial images,
and means for storing the extracted position information together with the
compressed data for all of said partial images into said store means; and
retrieval control means provided with the retrieval means, for reading out
only data representing the distinguishable partial image among said
divided partial images from said store means with reference to said
position information in response to a retrieval instruction, for expanding
the read partial image to produce image data, and for continuously display
the partial image data on said display means.
12. An image filing retrieving system according to claim 11, wherein said
fundamental unit to divide said image is equal to a screen size of said
display screen.
13. An image filing retrieving system according to claim 11, wherein from
the divided partial images, only one of said distinguishable partial
images is set.
14. An image filing retrieving system according to claim 11, further
comprising:
distinguishable partial image setting means for setting a distinguishable
part to a specific page within the divided partial images instead of
extracting the position information of said distinguishable partial image;
and,
means provided with said retrieval control means, for reading only the
partial image of said specific page from said store means in response to a
retrieval instruction, and for expanding the read partial image to obtain
image data to be continuously displayed.
15. An image filing retrieving system according to claim 14, wherein said
specific page corresponds to a first page of the divided partial images.
16. An image filing retrieving system according to claim 11, further
comprising:
means for setting plural items of distinguishable partial images, and for
expanding an arbitrary item of the partial image among said plural items
of distinguishable partial images in response to a retrieval response so
as to obtain image data to be displayed.
17. An image filing retrieving system according to claim 11, further
comprising:
complexity determining means for determining a complexity of the image
represented by a changing point number of pixels per a unit area with
respect to each of the divided partial images in response to an
instruction for setting a distinguishable partial image; and,
means for identifying the distinguishable partial image based upon a result
obtained by said complexity determining means.
18. An image filing retrieving system according to claim 16, further
comprising:
means for setting a specific position of a source image to a
distinguishable partial image.
19. An image filing retrieving system according to claim 16, further
comprising:
means for setting a partial image into which specific information has been
written, to a distinguishable partial image.
20. In an image filing system including an image data input device, store
control means for storing the image data inputted by said input device
into an optical disk, retrieval means for retrieving image data stored in
said optical disk, and a display screen having a predetermined display dot
number for displaying retrieved image data, a method of filing image data
comprising the steps of:
dividing all of the input image data representing an input image into a
plurality of partial images at said fundamental unit in response to an
input of image data for an input image which is larger than said display
screen can display at one time;
compressing each of the partial images and temporarily all of the partial
images as compressed data;
extracting position information of a distinguishable partial image among
the respective divided partial images; and
storing the extracted position information together with the compressed
data for all partial images into said optical disk.
21. A computer-aided-design (CAD) system for supervising a drawing
comprising:
coordinate input means for inputting a coordinate;
vectored drawing generating means for generating a vectored drawing based
upon the coordinate input by said coordinate input means;
vector/raster translator means for translating vector data of the drawing
generated by said vectored drawing generating means into image data;
store means for storing an image of the drawing which has been translated
into said image data;
retrieval means for retrieving said image stored into said store means;
a display screen having a predetermined display dot number for displaying
said image;
printing means for printing out said image;
image dividing means for dividing the input image at a fundamental unit
into partial images in response to the input image of the drawing larger
than said display screen, and for compressing the partial images so as to
be stored;
feature extracting means for extracting position information of a
distinguishable (featured) partial image among the respective divided
partial images;
means for storing said distinguishable partial image together with
compressed data into said store means; and,
retrieval control means provided with said retrieval means, for reading
only a distinguishable part among said divided partial images from said
store means with reference to said position information in response to a
retrieval instruction, and for expanding the read distinguishable part to
produce image data to be continuously displayed on said display screen. |
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Claims |
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Description |
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CROSS-REFERENCE TO RELATED APPLICATIONS
The present invention relates to U.S. application Ser. No. 469,383 filed on
Jan. 24, 1990, by Yasuo Kurosu et al based on Japanese Patent Application
No. 1-16146 filed Jan. 27, 1989; U.S. application Ser. No. 480,667 filed
on Feb. 15, 1990, by Yoshihiro Yokoyama et al based on Japanese Patent
Application No. 1-63625 filed Mar. 17, 1989, and relates to Japanese
Patent Application No. 1-63624 filed by Hitachi Limited on Mar. 17, 1989.
BACKGROUND OF THE INVENTION
The present invention relates to a processing technique for image data in
an electronic filing apparatus for use with an optical disk and the like.
In particular, the present invention is directed to a divisional file
method and a system for the image data used to realize high speed
retrieving of a large-sized drawing and the like by referring to the image
itself on an image display apparatus.
Recently, image file apparati have been practically utilized, and various
retrieval systems thereof have been studied. As is known, a method for
displaying an image for retrieval is very useful when image data is
retrieved, since such a method can make a direct appeal to an operator, as
compared with another retrieval method by way of a keyword and the like.
In general, a display screen of an image file apparatus has been
standardized with the CCITT protocols. for instance, an original-sized
display of an A4 size is fixed to 200 dots/inch (DPI). To the contrary, a
size of an image to be handled is different such that a document size is
from A0 to A3. More specifically, in the case where a data capacity (A0 to
A3) of a document is larger than the screen capacity (standard in A4) of a
display apparatus, an entire image cannot be displayed without further
processing. Then, while an image is inputted, when an image having a
display dot number greater than that of a screen of a display apparatus is
inputted, a guide image is formed by uniformly reducing the entire image
so as to fit this image to the screen of the display apparatus, and the
guide image is read out and displayed during the retrieving operation to
retrieve the desired image.
However, when a large-sized source image such as an A0 and A1-sized drawing
is uniformly reduced so as to be fitted with a screen having the normal A4
size. In recording the image on a recording medium, such as an optical
disk, the image is compressed due to the thinned-out operation affected
during the reduction, and there is a problem that a distinguishing part of
each image cannot be judged for legibility in reproduction.
Accordingly, one conventional method as described in JP-A-60-10771 has been
proposed to solve the above-mentioned problem.
In accordance with this conventional method, when a source or original
image is inputted into an optical disk device of a file apparatus, an
operator selectively extracts an arbitrary partial image from the source
image so as to form it as a guide image, and stores it together with the
source image into the optical disk. Then, in a retrieval operation, the
guide image within the optical disk is read out, and the guide images are
successively and continuously displayed on a display screen so that a
desired image is retrieved. When the desired image can be found from the
displayed guide images, the source image corresponding to the guide image
in concern is read out and then the retrieval operation is accomplished.
In accordance with the above-mentioned prior art, since the distinguishing
part of the source image can be observed at a glance, whereby an operator
can immediately specify the source image, a retrieval can be realized in
which convenient-to-use images are successively displayed to realize
retrieval based on the contents thereof.
In the above-mentioned prior art, since the guide images are separately
formed with respect to the source images and stored together with the
source images in the image storage device, such as an optical disk, an
extra file capacity for storing such guide images is required. Generally,
since the amount of data in an image is large, the extra file capacity
becomes large. In particular, when a plurality of guide images are formed
with respect to each source image, the required file capacity becomes
large. As a result, the number of images which can be stored in an optical
disk for providing the file capacity is reduced.
In the case where, for instance, a 1/8 partial image of a source image is
extracted therefrom so as to form a single guide image, image data is
increased by 12.5% of that of the source image.
Further, if a source image cannot be specified by a guide image, the source
image must be specified by observing a partial image other than the guide
image of the source image. However, according to the conventional method,
the partial image except for the guide image must be observed by reading
the source image so as to display this source image. However, at this
time, if compressed data of a source image having a large size such as A0
and A1 sizes are read out from the optical disk and expanded into image
data so as to be displayed on a screen, there occurs an inconvenience that
the display speed is lowered. For example, a time required for reading
from the optical disk, compressed data obtained by compressing image data
on an image having an A0 size and for expanding the compressed data so as
to produce the image data, is consumed 16 times longer than that required
for an image having an A4 size. As a consequence, the time required for
displaying an entire image having the A0 size on the screen becomes much
longer than that for displaying an image having the A4 size, and therefore
the machine interface is considerably deteriorated.
In U.S. Pat. No. 4,716,404 issued on Dec. 29, 1987, assigned to the present
assignee, a method has been proposed in which a distinguishing part of the
source image as a guide image is combined with memorandum information to
perform the image retrieval operation. However, no reference is made to
performing the file process of a source image having a large size.
Furthermore, the memorandum image forming technique has been disclosed in
U.S. Pat. No. 4,808,987 issued on Feb. 28, 1989 assigned to the present
assignee.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an image filing method and
an apparatus capable of filing an image having a large size, such as a
design drawing, multiplied by a standard display dimension while
suppressing a file capacity to a minimum value, and also capable of
retrieving the image at high speed.
Another object of the present invention is to provide a method and a system
in which when an image having a large size such as an A0-sized drawing and
an A1-sized drawing is handled, convenient-to-use images are successively
displayed on a display screen at high speed without requiring an extra
file capacity, and a retrieval operation is realized based on contents of
the displayed images.
A still further object of the present invention is to provide an image data
store medium for use with a filing system, which includes a data control
region for independently storing either position information on a
distinguishing part of an input image, or display priority information
thereof in connection with each image data, as well as an image data
region to file the input image in the form of a plurality of partial
images formed by dividing the input image into a unit image size.
To achieve the above objects, according to one feature of the present
invention, after an input image having a dot number larger than a
predetermined display dot number of a display screen (i.e., a source image
has been divided by a fundamental unit which has been previously defined
by the display dot number of the screen of the display apparatus) image
data of each of subdivided partial images are compressed (coded).
Simultaneously, either position information or address information of the
partial image containing a distinguishing feature of the input image is
extracted based on each of the partial image thus divided, and the
position or address information is stored together with compressed data
into a recording medium such as an optical disk. Thereafter, during the
retrieving operation, the position information stored in the recording
medium is referred to thereby to read image data of only the featured
partial image from the optical disk through expansion (decoding) of the
relevant compressed data, and the read image data is successively
displayed. With such an arrangement, an image data retrieval method and
system are provided by which image data can be retrieved at high speed
without requiring an extra file capacity such as a guide image filing
capacity.
Furthermore, in a featured part extraction according to an aspect of the
present invention, plural items of the featured partial images are set or
selected from the respective partial images which have been divided when
the source image is divided. For example, index information of a featured
partial image is formed and prepared in a recording medium or a retrieving
memory. The index information involves either a portion existing at a
specific position of a source image, or a portion to which specific
information has been described as present in the divided partial image.
Then, during the retrieving operation, while referring to the prepared
index information, only compressed data on an image of an arbitrary item
of the featured partial image among the above-mentioned plural items of
the featured partial images is read out from the recording medium, and
expanded (decoded) into image data to be displayed on a display screen.
On the other hand, in a featured part extraction according to another
aspect of the present invention, complexity is determined with respect to
a divided partial image based upon a binary change of an image pattern,
namely an alternation number from white to black, or black to white. A
region (image) having the highest complexity with the greatest alternation
number can be set as a most featured region (image). Also, the most
featured region is set to a first page among a plurality of divided
regions constituting an input image, i.e., at a head display order, and
stored in the recording medium. During the retrieving operation, only the
first page corresponding to the featured partial image of the respective
drawings is read out from the reading medium, and expanded into image
data. Thus, the expanded image data can be successively displayed on the
display screen.
A description will now be made of one operation mode of the image data
retrieving method and system according to the present invention. First,
when an image having a large size such as A0 and A1 size is inputted for
filing purposes, the input image is divided by a fundamental unit defined
by the screen size of the display screen. Image data representing the
respective divided partial images is compressed. At the same time,
position information of the partial image properly indicative of a feature
of the source image among the divided partial images is automatically
extracted and stored, together with compressed data of the partial image,
into the optical disk as the recording medium. Subsequently, when the file
is retrieved, only the partial image properly indicating the feature of
the source image among the respective partial images which have been
divided and stored, is read out from the optical disk based upon the
above-mentioned position information, and expanded into image data to be
displayed.
Accordingly, since a portion for representing most properly the feature of
the source image, such as the most complex portion of the source image, a
portion located at a specific position of the source image, or a portion
on which specific information has been described, is displayed, an
operator can specify the source image so that the image retrieving
operation effected by displaying only a portion of the source image can be
realized.
Further, in the case where the source image cannot be specified by the
first featured partial image, it is required to observe a partial image
other than the featured partial image of the source image. However, also
in this case, all of the source image data need not be read out from the
optical disk and need be expanded. While the display priority orders
corresponding to the feature degrees are applied to the respective partial
image, other partial images can be merely, sequentially read and expanded.
As a consequence, time required for reading and expanding is shortened.
Thus, the time required from a retrieval instruction by an operator until
generation of a display is reduced. The above-mentioned operation will now
be described with reference to a concrete example. For instance, it is
assumed that a source image having an A0 size has been divided into 16
partial images each having an A4 size, and each partial image is
compressed and stored into an optical disk. Thus, in the case where a
partial image other than the featured partial image is to be observed, it
is not necessary to read all of the compressed data of the stored source
image from the optical disk, but only compressed data for one of the
divided partial images may be read and expanded into image data. As a
result, the time required for the data expansion is reduced to 1/16, as
compared with the time required for expanding all of the image data of the
source image having the A0 size. Consequently, the time required for
displaying a partial image is shortened and the man-machine interface is
improved.
In accordance with the present invention, while images convenient to the
user are sequentially displayed at high speed, the retrieving operation
can be realized through the contents of the displayed images.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram for representing an embodiment of the present
invention;
FIG. 2 is an illustration for explaining an operation of a divisional file
system in FIG. 1;
FIG. 3 is a block diagram for indicating another embodiment of the present
invention;
FIG. 4 is an illustration of an index format employed in another
embodiment;
FIG. 5 is a block diagram of a further embodiment of the present invention;
FIG. 6A is a diagram for representing an arrangement of a further
embodiment;
FIG. 6B is a block circuit diagram for representing a concrete example of
the complexity counting circuit shown in FIG. 6A;
FIG. 7 is a Problem Analysis Diagram (PAD) for representing a process
sequence employed in the embodiment shown in FIG. 6A;
FIG. 8 is a diagram for indicating a process sequence so as to explain a
still further embodiment of the present invention; and,
FIG. 9 is an index format diagram employed in a registration sequence
utilized in the embodiment represented in FIG. 8.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to accompanying drawings, embodiments according to the
present invention will be described.
FIG. 1 shows a block diagram of an image data filing system according to an
embodiment of the present invention. Reference numeral 10 denotes an image
input unit, such as a scanner, for inputting image data, numeral 11
denotes a division unit for dividing the input image data into fundamental
units, numeral 12 denotes a distinguishing (featured) part setting unit,
numeral 13 denotes a compression (coding) unit for converting the divided
image data into compressed data, numeral 14 denotes an optical disk into
which the images have been stored in a compressed data form, numeral 15
denotes an expansion (decoding) unit for converting the compressed data
derived from the recording medium into image data, numeral 16 denotes an
input device including a keyboard and a pointing device, for inputting a
command and the like, numeral 17 denotes a display controller, numeral 18
denotes a display device such as CRT, for displaying the image, and,
numeral 19 denotes a control unit for providing control of various
processes of the overall system. It should be noted that the division unit
11 may be realized by employing a well known circuit, such as that
disclosed in, for example, JP-A-60-163169 (published on Aug. 26, 1985) and
JP-A-60-77271 (published on May 1, 1985).
In FIG. 2, there is shown an illustration of an input image, for explaining
the division filing method performed by the system of FIG. 1. It should be
noted in FIG. 2 that reference numerals surrounded by circles indicate
partial images which have been divided.
First, a registration sequence of input images will now be described. It is
assumed that an image having a large size, such as an A0 size, or an A1
size, has been inputted by the scanner 10. Subsequently, the input image
is divided based upon the screen size of CRT 18. For example, as
previously described, if a CRT display screen has a resolution of 200 DPI,
or approximately 1700.times.2400 dots, an A4-sized image corresponds to a
unit partial image. Assuming now that the input image is divided into
partial images 1 to 9, as represented in FIG. 2, an index representative
of the presence of a partial image for properly indicating plural featured
items of a source image among the divided partial images is formed in the
distinguishing part setting unit 12. For instance, it is assumed that as
the featured items, a designation is made to a central portion of a source
image, and particulars of figure numbers, titles and the like in a design
drawing so that the index is formed. For example, the portion 5 shown in
FIG. 2 is registered as a central portion in an index register unit
(referred to as an "index unit"), the portion 9 is registered in the index
unit as a portion of particulars, and it is indicated where each of the
portions is located on which sheet of the entire source image. It should
be noted that this registration operation may be performed by the
automatic registration means in the distinguishing part setting unit 12,
or by a manual registration while an operator inputs data. As this manual
registration means, for instance, the divided image data is sent to the
CRT control unit 17 and displayed on the CRT 18, so that while an operator
observes each partial image displayed on CRT 18, he instructs the input
device 16 to register them.
Then, to store as many images with a limited file capacity, partial image
data is converted into compressed data in the compression unit 13 in such
a manner that the image data of the respective partial images are
compressed. In other words, the partial image data is developed into bit
data. After the positions of the respective partial images have been
registered in an index area within a recording format of image data, both
the compressed data of the respective partial images and the index data
are stored into the optical disk 14.
Next, a retrieving sequence of a image will be described. An operator
selects partial images to be displayed as to a plurality of source images
from the above-mentioned plural featured items of the partial images. For
instance, when the central portion is selected to be retrieved, the
expansion unit 15 first reads out the index data from the optical disk 14.
In accordance with the read index data, only the central partial image of
the source image is read and expanded into image data. The expanded image
data is transferred to the CRT control unit 17 and then displayed on CRT
18.
In the above descriptions, control signals are supplied from the control
unit 19 to the respective circuit elements, and signals for reporting
conditions of the respective circuit elements are furnished to the control
unit 19. However, since such descriptions are not necessarily required for
a better understanding of the present invention, these descriptions and
illustrations are omitted for the sake of simplicity.
FIG. 3 is a block diagram of another embodiment of the present invention.
Reference numeral 30 denotes a scanner unit, numeral 31 denotes a division
unit, numeral 32 denotes a complexity detection unit for measuring the
complexities of the respective divided partial images, numeral 33 denotes
a compression unit, numeral 34 denotes an optical disk, numeral 35 denotes
an expansion unit, numeral 36 denotes a CRT control unit, numeral 37
denotes a CRT, and numeral 38 denotes a control unit.
In accordance with the embodiment, there is a particular feature that
instead of forming the index data, partial images for properly
representing the feature are combined into a specific page and set.
A description will now be made of an image recording sequence according to
the embodiment. Image data of an image inputted by the scanner 30 is
divided by a fundamental unit in the division unit 31 in a manner similar
to that of the first embodiment. Subsequently, the image data of the
respective partial images which have been divided are scanned in the
complexity detection unit 32 in an X-axis direction and a Y-axis
direction. That is to say, the image data is vector-scanned so as to
measure the number of changing points. In other words, the complexity of
the image is measured by counting frequencies of changes from white to
black, or from black to white. Thereafter, the image data of the
respective partial images is compressed so as to produce compressed data
in the compression unit 33. Then, the partial image having the highest
complexity among a plurality of partial images divided from the respective
source images is stored into the optical disk 34 in such a manner that the
first-mentioned partial image is located at a first page of these entire
partial images, i.e., a head store position.
Subsequently, an image retrieving sequence will now be described. At first,
compressed data relating only to the first page corresponding to the
featured portion of each of the images are successively read out from the
optical disk 34, and then converted into image data in the expansion unit
35. The converted image data is delivered to the CRT control unit 36 and
displayed on CRT 37.
Also, in the above explanations, control signals are supplied from the
control unit 38 to the respective circuit elements, whereas signals for
announcing conditions of these circuit elements are furnished to the
control unit 38, similar to those of the first embodiment shown in FIG. 1.
Referring now to FIG. 4, a division filing method of image data according
to a embodiment will be described. In this filing method, when an input
image is larger than a display screen, after the input image has been
divided by a basic unit, the divided images are compressed and
simultaneously position information of a partial image indicative of a
particular feature of a source image is extracted, and further stored
together with the compressed data of the image.
First, an index format of each source image, as represented in FIG. 4, is
formed. Here, a data field 40 is a title unit for registering a title of
an image to be stored, a field 41 is a divisional number unit for
registering a divisional number, a field 42 corresponds to a
distinguishable region unit for indicating which partial image properly
represents a feature of a source image, and a field 43 denotes an address
unit for registering an address of each partial image on an optical disk.
As to the field 42, a plurality of items to define a distinguishable
partial image are previously determined. For instance, it is assumed that
a set has been made to both a central portion of the source image and a
second item of the distinguishable partial image having the highest
complexity.
Thus, an index represented as a concrete example is formed. At first,
titles of input images can be registered up to 10 characters. In case of
10 characters, 160 bits (=16(2 bytes).times.10) are allocated to KANJI
characters, whereas 80 bits (=8(1 byte).times.10) are allocated to
alphanumeric characters. Accordingly, the title unit 40 requires 160 bits
(=16(2 bytes).times.10). Then, assuming that the division pages for the
input image are 31 at a maximum page, the divisional number unit 41
requires 5 bits. Next, it can be registered in the distinguishing part
setting unit 42 that the respective items of the featured partial image
are present in a page of an entire source image. Since the input image is
divided in 31 pages at the maximum, 5 bits are required for each item.
Now, as two items have been set, the distinguishing part setting unit
requires 10 bits. Then, while the compressed data of the respective
partial images are stored in the optical disk, the positional addresses to
record the respective partial images are registered in the address unit
43.
In general, a memory capacity of a 5-inch optical disk is approximately 0.6
G bytes. If a sector functioning as a minimum data unit is selected to be
40 K bytes, there are provided about 1,500 sectors in this optical disk.
As a result, each address to access this optical disk requires 14 bits.
Since both a head address and an end address of a position where
compressed data of each image is recorded need to be registered, 28 bits
are necessary for each of the partial images. Accordingly, as represented
in FIG. 2, when an input image is divided by 9, the address unit 43
requires 252 bits (=28.times.9).
Therefore, an index length of this input image becomes 427 bits in total.
Next, a concrete registration procedure of an image will now be described.
When an image is first inputted, a title of the input image is registered
in the title unit 40. Subsequently, the input image is divided based upon
a fundamental unit defined by a screen size of a display device. Now
assuming that, as represented in FIG. 2, the input image has been
subdivided into 9 partial images 1 to 9, the division number 9 is
registered into the division number unit 41. Thereafter, a partial image
properly indicative of a feature (distinguishable part) of a source image
among the respective partial images is registered in the distinguishing
part setting unit 42 of the index. In FIG. 2, for example, the partial
image 5 corresponding to the central portion of the source image is
registered as a central portion, whereas the partial image 9 corresponding
to the portion having the highest complexity is registered as a portion
having a high complexity. Then, the image data of each partial image is
compressed. While, the compressed data of the respective divided partial
images are stored into the optical disk, both the head address and end
address of the position where the respective partial images are stored are
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