JP2994047B2 - Information recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording / reproducing apparatus for recording and reproducing information.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional example of a system for receiving an image distribution service such as a TV telephone and a CATV, and recording and reproducing the service. In the figure, 401 is an input terminal, 402 is a demodulation circuit for received data, 403 is an error correction circuit, 406
Is a modulation circuit, 408 is a recording medium such as a magnetic disk, 40
9 is a demodulation circuit, 411 is a decoding circuit, and 412 is an output terminal.

[0003] Compressed data that has been subjected to transform coding (for example, DCT or Hadamard change) or block coding is input to an input terminal 401 in accordance with the band of the transmission path. Received data input via the input terminal 401 is received and demodulated by the reception demodulation circuit 402 and error correction 403 is performed.
Then, the error on the transmission path is corrected and sent to the modulation circuit 406. The modulation circuit 406 adds error correction, modulates, and records the data on the recording medium 408 (in this case, a magnetic disk).

On the other hand, when reproducing, a demodulation circuit 409
Demodulation, error correction, decoding of the transform-encoded or block-encoded data by the decoding circuit 411, output to the output terminal 412, and output to an output device such as a monitor to view the image. it can.

[0005]

However, in the above conventional example, when trying to search for certain information recorded on a recording medium, the recorded data must be read in order from the beginning and decoded / reproduced. Not even,
At that time, it takes time to read out the compressed data from the recording medium and to perform the decoding process, so that there is a problem that it takes more time than necessary for the search.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem. A low-frequency component is extracted from image information, and the size of search information for each screen is obtained based on the extracted low-frequency component. Recording / reproducing apparatus and method capable of quickly obtaining search information by storing search information in a storage medium and reproducing search information for each screen based on the size information at the time of reproduction. What you want to do.

[0007]

To solve this problem, for example, an information recording / reproducing apparatus according to the present invention has the following arrangement. That is, extraction means for extracting low-frequency components from given image information, and, based on the low-frequency components extracted by the extraction means, information on the size of search information required for each screen to be searched for. Generating means for generating, storage control means for storing the size information generated by the generating means in the storage means together with the image information, and reproduction for reproducing the search information for each screen based on the size information Means.

[0008]

In the configuration of the present invention, a low-frequency component is extracted from the given image information, and the size of the search information for each screen required for the search is determined based on the extracted low-frequency component. Generate information. Then, the generated size information is stored in the storage unit together with the image information.

[0009]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a block diagram of the recording / reproducing apparatus of the embodiment. In the figure, 101 is an input terminal for received data,
102 is a reception demodulation circuit, 103 is an error correction circuit, 10
4 is a low-frequency component detection circuit of received data, 105 is an ID addition circuit, 106 is a modulation circuit, 107 is a mode and timing control circuit of the present apparatus, 108 is a disk serving as a recording medium, 109 is a demodulation circuit, 110 Is an ID detection circuit, 111 is a decoding circuit for decoding data compressed by transform coding or block coding, and 112 is an output terminal.

In the embodiment, the received data is DC
It is assumed that encoding is performed by orthogonal transform such as T, Hadamard transform. At the time of recording, received data input from an input terminal 101 is demodulated by a received data demodulation circuit 102 and sent to an error correction circuit 103. The error correction circuit 103 corrects the error of the received data on the transmission path, and the low-frequency component detection circuit 104 and the ID addition circuit 1
05. The low frequency component detection circuit 104 detects a frequency component lower than a certain frequency of the received data, and sends a detection signal to the control circuit 107. In the control circuit 107, based on the detection signal sent from the low-frequency component detection circuit 104, the information on the magnitude of the low-frequency component and the ID (for example, corresponding to the recording order) for each screen necessary for the search. Sequence number) and sends it to the ID addition circuit 105. ID addition circuit 1
In step 05, the information of the magnitude of the low-frequency component and the ID transmitted from the control circuit 107 are added to the original received data, and transmitted to the modulation circuit 106. The modulation circuit 106 adds error correction for recording, modulates the data, and records it as recording data on a recording medium 108 (in this case, a disk).

In the case of normal reproduction, data read from the disk 108 under the control of the control circuit 107 is sequentially output to the demodulation circuit 109 in the same manner as in the conventional example described above.
, Demodulates the error, corrects the error, sends the result to the decoding circuit 111, decodes the orthogonally transformed coded data, and sends it to the output terminal 112. If it is desired to know what is recorded on the disk 108, the ID detection circuit 110 detects the ID and size information from the reproduction data from the demodulation circuit 109, and controls so as to read only the low-frequency component of the recording data. The circuit 107 controls reading from the disk 108. By doing so, the decoding circuit 111 need only decode the low-frequency components.

For example, if decoding is to be performed using only DC components, the original information is quantized by 8 bits, and the size of a block for encoding is 8 × 8, and is compressed to 1/10. Assuming that the DC component is represented by 8 bits, 8 ÷ (8 × 8 × 8 × 1/10) ≒ 0.16,
A search screen can be created with about 16% of the encoded information amount.

As described above, a faster search can be realized by recording the size and ID of the low-frequency component at the time of recording and reading and decoding only the low-frequency component at the time of reproduction. If the received data has been encoded by block encoding, the low-frequency component detection circuit 104 detects an average value and the like, and at the time of retrieval, the decoding circuit 111 performs decoding only with the average value. In this case, the same effect as above can be obtained.
At the time of retrieval, data is read out in the same manner as in normal reproduction, and I
By decoding only the low-frequency component from the information of D and the size and not decoding the remaining components, an effect similar to the above-described effect can be obtained without performing complicated disk read control.
In this embodiment, a magnetic disk is taken as a recording medium, but the recording medium is not limited to a disk, and may be a tape or the like.

<Second Embodiment> FIG. 2 is a block diagram of a recording and reproducing apparatus according to a second embodiment. The components having the same functions as those in the first embodiment are given the same numbers. Hereinafter, the same parts as those in the first embodiment will be omitted, and only different points will be described. The low frequency component is extracted by the low frequency component extraction circuit 201 from the received data transmitted from the error correction circuit 103. To the low-frequency component extracted by the low-frequency component extraction circuit 201, the control circuit 107 adds an ID and size information of the low-frequency component for each screen necessary for the search.
The insertion circuit 202 inserts and records the low-frequency components collectively at one location for each frame or for each field. By doing as described above, it is possible to read out only the low-frequency component faster, and it is possible to perform a faster search.

<Third Embodiment> FIG. 3 is a block diagram of a recording / reproducing apparatus according to a third embodiment. The components having the same functions as those of the first and second embodiments are given the same numbers.
At the time of retrieval, the decoding circuit 111 decodes only the low-frequency components of the data read from the disk 108 to create a small screen, and sends it out to the memory 301 to record it on the memory 301. Similarly, small screens are created one after another, and the memory 3
01 is recorded. When n multi-screens (depending on the size of the display screen) are recorded in the memory 301,
The memory 301 outputs a multi-screen to the output terminal 112.

According to the above-described method, it is possible to search on a multi-screen without having to record the multi-screen in advance. Note that, in this case, which image is to be inspected while viewing the displayed screen is clicked on the display screen with a mouse or the like. Since you can find out which small screen was selected by calculating backward from the click position,
The actual image data is output using the identified ID for the small screen.

As described above, in a system for recording and reproducing image data compressed using transform coding or block coding, a low-frequency component detecting circuit, a DC component detecting circuit such as an average value, or an extracting circuit By recording the ID and the size information,
Faster search can be realized.

[0018]

As described above, according to the present invention, a low-frequency component is extracted from image information, and the size of search information for each screen is obtained based on the extracted low-frequency component. Since the information is stored in the storage medium, the search information is reproduced based on the size information for each screen at the time of reproduction, so that the search information can be obtained quickly.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image recording / reproducing apparatus according to a first embodiment.

FIG. 2 is a block diagram of an image recording / reproducing apparatus according to a second embodiment.

FIG. 3 is a block diagram of an image recording / reproducing apparatus according to a third embodiment.

FIG. 4 is a block diagram of a conventional image recording / reproducing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS 101 input terminal 102 reception demodulation circuit 103 error correction circuit 104 low frequency component detection circuit 105 ID addition circuit 106 modulation circuit 107 control circuit 108 disk 109 demodulation circuit 110 ID detection circuit 111 decoding circuit 112 output terminal

Claims (2)

(57) [Claims] 1. An extracting means for extracting a low-frequency component from given image information, and a size of search information for each screen required for searching based on the low-frequency component extracted by the extracting means. Generating means for generating information of the following; storage control means for storing the size information generated by the generating means in the storage means together with the image information; and searching information for each screen based on the size information. An information recording / reproducing apparatus, comprising: reproducing means for reproducing. 2. An extraction step of extracting a low-frequency component from given image information, and a size of search information for each screen necessary for a search based on the low-frequency component extracted in the extraction step. A generating step of generating the information of the following; a storage control step of storing the size information generated in the generating step together with the image information in a storage unit; based on the size information, the search information for each screen. And a reproducing step for reproducing.