JPH04373281A - Retrieving circuit for image file disk device - Google Patents

Abstract

PURPOSE:To rapidly retrieve a desired image file with sure. CONSTITUTION:A first digital image data a' which is obtained by the digital/ analogue conversion of an image signal a is recorded in the a specified area 45 in a disk 1. The image signal a is thinned out by a thinning means 3 to become a second digital image data a'', and then it is compressed by a compressing means 4 to become an image data a'''. A character data b' corresponding to the image signal a is recorded along with the image data a''' by a second recording means 5 in the second specified area 44 in the disk 1. A reproducing means 6 reproduces the image data a''' and the character data b' recorded in a second specified area 44.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a search circuit for an image file disk device, and more particularly to a search circuit for an image file disk device that records and reproduces search data in a directory area provided on a disk.

0002

2. Description of the Related Art Conventionally, image file disk devices (hereinafter abbreviated as devices) for recording and reproducing still image data obtained by digitizing image signals on disks have been known. FIG. 4 shows a disk used in an image file disk device, that is, an MO disk (Magneto disk).
FIG. 2 is a diagram showing an example of a format of an optical disc. In FIG. 4, 1 is an MO disk (disk).

The MO disk 1 is roughly divided into a control area 41, a user area 42, and a control area 43 from the inner circumferential side. The control areas 41 and 43 are calibration areas in which data for setting the recording power of the device to suit the disc medium are recorded, and data for optimizing the recording and playback characteristics of the device in accordance with the disc medium. It consists of control tracks, etc. The user area 42 is prepared so that the user can freely record and reproduce data.

In a conventional image file disk device, a directory area 44 is provided on the inner circumferential side of the user area 42, and characters (numbers) are provided as search information corresponding to still image data recorded in a data area 45 provided on the outer circumferential side. ) A search circuit for an image file disk device that records and reproduces data is known.

FIG. 5 is a block diagram of a recording system of an example of a search circuit of a conventional image file disk device, and FIG. 6 is a block diagram of a reproduction system of an example of a search circuit of a conventional image file disk device.

In FIG. 5, an image signal a is converted into digital image data a' by an analog-digital conversion circuit 11.
and via the switch S1 and the recording modulation circuit 17,
The data is recorded in the data area 45 of the MO disk 1 by the laser diode D1. On the other hand, the character data b is converted into digital character data b' by the encoding circuit 15, and is converted into the directory area 44 of the MO disk 1 by the laser diode D1 via the switch S1 and the recording modulation circuit 17.
recorded in

The switch S1 selectively outputs either image data or character data to the recording modulation circuit 17 depending on the area of the MO disk 1 to be recorded.

In FIG. 6, the output of the photodiode D2 which has detected the data recorded on the MO disk 1 is input to the reproduction demodulation circuit 18, where it is reproduced and demodulated, and then sent to the digital-to-analog conversion circuit 19 via the switch S2. It is selectively output to one of the decoding circuits 25.

The switch S2 is switched in synchronization with the switch S3 according to the detection area on the MO disk 1. That is, when image data is detected in the data area 45, the digital-to-analog conversion circuit 19 is connected to the reproduction demodulation circuit 18 and the output amplification circuit 27, and when character data is detected in the directory area 44, the decoding circuit 25 is It is connected to the reproduction demodulation circuit 18 and the output amplification circuit 27.

As a result, the image data a' recorded in the data area 45 of the MO disk 1 is converted into an analog image signal a by the digital-to-analog conversion circuit 19, and then sent to the display device 28 via the output amplification circuit 27. The image is displayed on the display device 28. Similarly, the digital character data b' recorded in the directory area 44 is converted into an analog character signal b'' by the decoding circuit 25, and the characters are displayed on the display device 28.

According to the search circuit configured as described above, data such as a title corresponding to the content of the still image data recorded in the data area 45 and a chapter number indicating the position on the MO disc where the still image data is recorded are retrieved by characters (numerals). ) could be recorded in the directory area 44 as data. and,
Play back the directory area 44 of the MO disk and write the characters (
The numeric) data was displayed on the display device as an index, and by looking at it, it was possible to search for the desired still image data.

0012

However, in the search circuit of the conventional image file disk device, only character (numeric) data can be recorded as an index in the directory area 44. Therefore, when searching for a desired image from among the many still image files recorded on the MO disk, it was necessary to rely only on the characters (numbers) displayed on the display device.

[0013] If there is a clear correspondence between the contents of the still image file and the index characters (numbers), it is not difficult to search for the desired image, but if many images with similar contents are recorded, However, it was extremely difficult to clearly differentiate each image by assigning index characters (numbers) corresponding to the images.

[0014] In such a case, the index character (number)
Even if you search for the desired image, there are many cases where other similar images are found, and you may have to actually check the images and repeat the search several times to find the desired image. Ta. If only character (numeric) data is used, the usefulness of the directory area 44 as an index is low, and it may be difficult to quickly and reliably search for a desired image.

In view of the above points, it is an object of the present invention to provide a search circuit for an image file disk device that can quickly and reliably search for a desired image file.

[0016]

[Means for Solving the Problems] In order to solve the above problems, the present invention is constructed as shown in the principle diagram shown in FIG.

That is, the first digital image data a' obtained by analog-to-digital conversion of the image signal a is transferred to the disk 1.
a first recording means 2 for recording in a first predetermined area 45;
When converting the image signal a from analog to digital, the image information is thinned out and the second digital image data a''
a compression means 4 for compressing the second digital image data a''; and a compression means 4 for compressing the second digital image data a'', and character data b corresponding to the output image data a'' of the compression means 4 and the image signal a.
a second recording means 5 for recording ' in a second predetermined area 44 of the disc 1, and a reproducing means 6 for reproducing image data a''' and character data b' from the second predetermined area 44 of the disc 1. It was configured by providing

[0018]

According to the present invention having the above structure, the first digital image data a' obtained by analog-to-digital conversion of the image signal a is recorded in the first predetermined area of the disk. On the other hand, the image signal a is thinned out by a thinning device and compressed by a compression device to reduce the amount of information as image data a''', which is recorded and reproduced in a second predetermined area of the disk. The character data b' is also recorded and reproduced together with the image data a''' in a second predetermined area other than the first predetermined area where the first digital image data a' is recorded and reproduced.

[0019]

Embodiment FIG. 2 is a block diagram of a recording system according to an embodiment of the present invention, and FIG. 3 is a block diagram of a reproduction system according to an embodiment of the present invention. In each figure, the same components as those in FIGS. 5 and 6 are denoted by the same reference numerals, and the description thereof will be omitted as appropriate. An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, the image signal a is analog-
It is input to digital conversion circuits 11 and 12. The output image data a'' of the analog-to-digital conversion circuit 12 (thinning means) is input to the orthogonal transform encoding circuit 13 (compression means).
The signal is supplied to the variable length encoding circuit 14 (compressing means) via. The output image data a''' of the variable length encoding circuit 14 is added with the output character data b' of the encoding circuit 15 by an adder 16, and is supplied to the switch S1, and then is sent to the laser diode D1 via the recording modulation circuit 17. Drive the MO
It is recorded in the directory area 44 of the disc 1.

The analog-to-digital conversion circuit 12 is a so-called sub-conversion circuit that samples the image signal a at a frequency that is 1/n of the sampling frequency of the analog-to-digital conversion circuit 11 and omits encoding for each pixel to reduce the amount of information. Perform sampling. As a result, the amount of information in one image is 1/
n, and the size on the screen of the display device is also 1/n.
It is said that

As is well known, the orthogonal transform encoding circuit 13 uses discrete cosine transform to eliminate frequency component redundancy and reduce the amount of data, and the variable length encoding circuit 14 uses Huffman encoding to generate an optimal code. It is configured to allocate data to reduce the amount of data and perform high-efficiency encoding.

With the above configuration, the directory area 44 contains image data a' that has been thinned out to 1/n and further compressed.
'' (hereinafter referred to as an index image) is recorded together with character data b'.

Next, in FIG. 3, photodiode D2
Image data a''' and character data b of the index image recorded in the directory area 44 detected by
' is the RA via the regenerative demodulation circuit 18 and the switch S1.
The data is supplied to M (random access memory) 20. R.A.
M20 receives image data a''' by the access circuit 21.
and reading and writing of character data b' are controlled.

The access circuit 21 operates the switch S according to the search signal c input when searching for a still image file.
Its operation is controlled together with 2 and S3.

Image data a read out from RAM 20
''' is supplied to the orthogonal transform decoding circuit 23 via the variable length decoding circuit 22 and decoded into image data a''. The decoded output image data of the orthogonal transform decoding circuit 23 is input to the digital-to-analog converter circuit 24, where it is converted into an analog image signal a'''' obtained by dividing the screen into 1/n.

On the other hand, the character data b' read out from the RAM 20 is converted into an analog character signal b' by the decoding circuit 25.
', is added to the analog image signal a'''' output from the digital-to-analog conversion circuit 24 by the adder 26, and is displayed on the display device 28 via the switch S3 and the output amplification circuit 27.

By the way, the directory area 44 has a format that allows digital recording and reproduction, and the larger the capacity, the higher the image quality of the index image can be. However, if the capacity of the directory area 44 is set to be large, the capacity of the data area 45 will be correspondingly reduced, and the amount of image files that can be recorded will be reduced.

For example, one frame of an NTSC standard television signal is sampled at a sampling frequency of 14.3 MHz (4
fsc) and performs 8-bit quantization, the amount of information is approximately 500 Kbytes. This one frame signal is subsampled at 14.3/n [MHz],
Assume that high-efficiency encoding is performed at a compression rate of 1/55.

[0030] At this time, the amount of information PID for one index image is PID=500/n/55 [kilobytes]
becomes.

[0031] Also, at this time, if approximately 50 characters of character data are assigned as index characters to one index image, and if each character is recorded in 1 byte, the amount of information CID for the index character is CID
=50 [bytes].

Therefore, the information amount DI of one index
D is a combination of index images and index characters, and if n=20, then DID=PID+CID
=(500/20/55)×10
3 +50=505
=505
〔Part-Time Job〕
It becomes necessary.

On the other hand, taking an ISO 130 mm magneto-optical disk as an example, there are two format types: type A (continuous servo system) and type B (sampling servo system). Type A sector size is 1024
Bytes/Sector or 512 Bytes/Sector, Type B sector size is 512 bytes/sector.

[0034] Therefore, with the information amount of 505 bytes/index, it is possible to record two indexes in one sector in the case of 1024 bytes/sector, and one index in one sector in the case of 512 bytes/sector. .

According to the above embodiment, it is possible to display index images obtained by dividing the screen of the display device 28 into 20 parts. Since the index image is thinned out from the still image file itself to have a screen size of 1/20, it has a one-to-one correspondence with the contents recorded in the data area. Furthermore, since title characters are displayed on the screen along with the index image, it is possible to quickly and reliably search for still image files.

[0036]

As described above, according to the present invention, character data and image data can be reproduced from a second predetermined area other than the first predetermined area where image data is recorded and reproduced, so that desired image data can be quickly retrieved. It also has the advantage of being able to be found reliably.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of the present invention.

FIG. 2 is a block diagram of a recording system according to an embodiment of the present invention.

FIG. 3 is a block diagram of a reproduction system according to an embodiment of the present invention.

FIG. 4 is a diagram showing an example of the format of an MO disk used in an image file disk device.

FIG. 5 is a block diagram of a recording system of an example of a search circuit of a conventional image file disk device.

FIG. 6 is a block diagram of a reproduction system of an example of a search circuit of a conventional image file disk device.

[Explanation of symbols]

1 MO disk (disk) 2 First recording means 3 Thinning means 4 Compression means 5 Second recording means 6 Reproducing means 12 Analog-digital conversion circuit (thinning means) 1
3 Variable length encoding circuit (compression means) 14 Orthogonal transform encoding circuit (compression means) 22 Variable length decoding circuit (reproduction means)

Claims (1)

[Claims] 1. A first recording means for recording first digital image data obtained by analog-to-digital conversion of an image signal in a first predetermined area of a disk; a thinning means for thinning out information to generate second digital image data; a compression means for compressing the second digital image data; An image file disk comprising: a second recording means for recording in a second predetermined area of the disk; and a reproduction means for reproducing the image data and the character data from the second predetermined area of the disk. Device search circuit.