JPH07122048A - Digital video tape recorder - Google Patents

Abstract

PURPOSE:To continuously reproduce index images and to easily and rapidly retrieve recording images by recording the static images stored in a memory means for index in the margin region disposed at the front end of a video tape. CONSTITUTION:A sub-code detecting means 13 detects start signals for index recorded in the sub-code regions disposed at every one track of the tape 1. A control means 14 executes reproduction operation once by controlling a memory 15 for index, extracts the DC and low-frequency components of the image data in a memory 11 and stores these components in the memory 15. A video recording means 16 adds an error correction code to the image data of the memory 15 and records the data in the margin region at the top of the tape and continuously reproduces the data, thereby obtaining the index images. As a result, the erasing of the images does not arise and the contents of the image of the recording tape are easily and rapidly retrieved even if the power source of the IC memory is turned off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an index function suitable for image retrieval in a digital video tape recorder.

[0002]

2. Description of the Related Art Conventionally, there is a video tape recorder of a type capable of recording a control signal for retrieval on a control track of a magnetic tape, and by using this control signal, high speed cueing can be performed. is there. However, when performing a search without knowing the contents recorded on the magnetic tape, a high-speed cue is performed sequentially from the beginning of the tape, the screen obtained by the cue is reproduced for several seconds, and this search operation is continued. To select the desired screen.

[0003]

In the conventional video tape recorder, it takes a lot of time to retrieve a necessary image from many kinds of images recorded on the tape.
It was difficult to find the desired image in a short time.

Therefore, it is an object of the present invention to provide a digital video tape recorder having an index function which makes it possible to easily know the contents of a recorded tape by utilizing the characteristics of a digital image recording / reproducing apparatus. .

[0005]

In order to achieve the above object, in the first aspect, an index for preliminarily defining a blank area at least at the beginning of a video tape and storing image data extracted for each scene. Storage means,
There is provided a digital video tape recorder, comprising: a recording unit that records the stored image data in the blank area.

In the second aspect, a digital video having a sub-code area for recording an auxiliary control signal in a part of a track of a video tape and an auxiliary control signal recording means for recording the auxiliary control signal. In the tape recorder, the sub-code detection means for detecting the index start signal recorded for each scene by the auxiliary control signal recording means, and the index start signal detected during high-speed operation of rewinding or fast-forwarding the video tape Digital video tape recorder, comprising: a control means for extracting image data where the index start signal is recorded, and an index storage means for storing the extracted image data. provide.

Further, in the third aspect, claim 1,
There is provided a digital video tape recorder characterized by having both of the features of (2).

A second aspect of the present invention provides the digital video tape recorder, wherein the control means extracts only the data of the DC component and the low frequency component from the compressed image data.

Further, the control means according to the second aspect has the features of both claims 1 and 2, and extracts only the data of the direct current component and the low frequency component from the compressed image data. To provide a digital video tape recorder.

[0010]

According to the first aspect of the present invention, a margin area is provided in advance at the head portion or the trailing edge of the video tape, and the still image stored in the index storage means is recorded in this margin area. Even if the power of the IC memory is turned off, there is no possibility that the image will be erased, and the index images can be continuously reproduced, so that the recorded contents can be instantly known. It should be noted that the place where the image is recorded is not limited to the head portion or the rear end portion of the tape, and it can be any portion, and the head portion is particularly suitable. (Claim 1)

As a mode of extracting image data from the second viewpoint, an index start signal is recorded in the subcode area of the video tape for each scene, for example, each time recording is started, and the index start signal is used for rewinding or fast-forwarding the tape. 1 each time a start signal is detected
The image data of the field or one frame is automatically stored in the index storage means including an IC memory.

Unlike the present invention, when the index image data is directly stored in the IC memory each time recording is started, for example, in a video-integrated camera, the power is completely turned off when the battery is replaced, and the IC memory Although the contents are erased and the index image disappears, in the present invention, the index images are collectively stored in the IC memory when the tape is rewound or fast forwarded. An image can be created (Claim 2). Furthermore, after extracting the still image data by the above method and recording it in the blank area of the tape, the index image can be stored more reliably (claim 3).

Further, since the signal handled is a digital signal, the image signal can be easily temporarily recorded in the IC memory as an index image without increasing the circuit scale.

In a digital image device, code compression of an image is performed in order to record the information with a minimum amount of information. DCT (Discrete Cosine Transform) code compression is often used for image code compression. In this DCT code compression, the amount of information is small because the high frequency components are highly correlated, and the information of the DC component and the low frequency component is reduced. The quantity is increasing.

In the present invention, the DC and low frequency components of the DCT code compression are effectively used for the monitor display of the index image to create a multi-image (claim 4).

Furthermore, by integrating the above methods, a plurality of index images are automatically recorded as multi-images in the blank area of the tape formed by partitioning (claim 5).

[0017]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 shows a block diagram of the present invention. The reproduction signal is input to the amplification means 1, amplified, and output to the equalizer 2. The equalizer 2 corrects the frequency characteristic and shapes the signal waveform. This output signal is input to the comparator 3 and the PLL (Phase Locked Loop) circuit 4. The PLL circuit 4 generates a read clock signal in synchronism with the recording signal, and the comparator 3 converts the signal input from the equalizer 2 into a binarized signal based on this clock signal.

The binarized signal is input to the memory 5, and the time variation at the time of reading the signal is absorbed by the memory 5. The output of the memory 5 is connected to the input of the serial / parallel conversion means 6, and the serial / parallel conversion means 6 is connected. Are converted into parallel signals and output. The parallel signals are input to the synchronization detection means 7 which detects the synchronization signal and the ID code.

In the digital image recording / reproducing apparatus, the signal is divided into unit blocks, for example, every 90 bytes, and a synchronization signal and an ID indicating the order of the blocks are provided for each unit block.
The code and is added.

After the sync signal and the ID code are detected, the signals are input to the memory 8 and rearranged in a normal form, and the rearranged signals are error detection / correction means 9 and subcode detection means 13, And audio circuit (not shown)
Is output to.

The Reed-Solomon code correction is performed in the error detection / correction means 9, and the uncorrectable error signal is used in the next error correction means 10 by utilizing the correlation of the image and the signal of one frame before or one line before. The signal is inserted. The output signal of the error correction means 10 is input to the memory 11, and together with the image expansion means 12 connected to the memory 11, the code-compressed image signal is expanded and converted into a normal video signal, and a video output circuit (not shown). Output).

On the other hand, the subcode detecting means 13 detects the subcode signal of the subcode area provided for each track of the tape. Information such as a time record, record data, or date and time can be recorded in the sub-code area. In the present invention, an index start signal for controlling the index memory 15 described later is recorded.

The index start signal detected by the subcode detecting means 13 is input to the control means 14 and a servo system circuit (not shown), and for example, when the tape is rewound, the index start signal is supplied. When the index is detected, the control means 14 controls the index memory 15 and the servo system circuit sets 1
The reproduction operation is performed once.

The image data compressed by the DCT code is
Since the DC component and the high frequency component are regularly arranged in the memory 11 for each frequency component, the control unit 14 extracts the DC and low frequency components of the DCT code compressed signal and stores them in the index memory 15. It Then, the image data of the index memory 15 is output to the recording means 16, and the error correction code is added to the image data, and the image data is recorded in the set margin area at the beginning or the end of the tape.

FIG. 2 shows the state of the tracks recorded on the tape, and FIG. 3 shows the track pattern. The track pattern includes a video information area for one field, an audio information area for an amount corresponding to the time for one field, a subcode area for recording a time record or the like and an index start signal in the present invention. Margin area to prevent, ATF area for auto tracking control, and I of card band
It consists of a BG area.

Next, the operation using the index start signal in the present invention will be described.

As a first embodiment, an operation of automatically creating an index image will be described. First,
An area for recording an index image is secured in advance on a part of the tape (preferably at the beginning or end), and an index start signal is added to the subcode area each time the scene changes, for example, every time recording starts. Record. The index start signal is recorded by auxiliary control signal recording means (not shown).

After the recording, when the user presses the index creation switch provided in the device of the present invention, the tape is rewound or fast forwarded to the beginning or the end at high speed,
The index start signal is detected during rewinding or fast-forwarding. When a signal is detected, reproduction is performed once in the forward direction, a signal of one field or one frame is extracted, and image data is stored in the index memory 15. This detection and storage is repeated, and finally the index memory 1
The data of No. 5 is recorded by adding an error correction code to the index image recording area of the blank area provided in advance on the tape.

FIG. 4 shows a flow chart of the first embodiment. The above operation will be described in detail below with reference to FIG. In the embodiment, the index image is recorded at the beginning of the tape. First, in step # 1, whether or not the tape is at the beginning is determined by, for example, an LED and a light receiving sensor.
If it is at the beginning, in step # 2, the tape is advanced in order to secure an index image recording area for, for example, ten or more frames at the beginning of the tape. If it is not the beginning step # 3
Perform the process of. At step # 3, an index start signal is recorded in the subcode area of the track simultaneously with the start of recording.

After the recording, in step # 6, if the user does not press the index creation switch, the operation ends,
If the switch is pressed, the tape is rewound to the beginning in step # 7, and the index start signal is detected in step # 8 during rewinding. When this start signal is detected, reproduction is performed in the forward direction in step # 9, and the DC and low frequency components of the DCT code-compressed data in the image data of one field or one frame are extracted and stored in the index memory 15. Store the data.

Next, in step # 10, it is detected whether or not the tape has returned to the beginning, and the operations from step # 7 to step # 9 are repeated until it returns to the beginning. When returning to the beginning, in step # 11, the data stored in the index memory 15 is recorded with the error correction code added to the index image recording area of the tape, and the series of steps is completed.

As a second embodiment, an operation of creating an index image of only the image selected by the user will be described.

FIG. 5 shows a flowchart of the second embodiment. First, an index image recording area is secured in a part of the tape (steps # 1 and # 2), and after the recording is completed (steps # 3 and # 4), the user reproduces the tape and watches the index image. Select the image you want to record in the recording area.

The DCT code-compressed DC and low frequency components of the selected one field or one frame image are extracted and stored in the index memory 15 (steps # 5 to # 8). When the required image is selected and the reproduction is completed, the tape is rewound to the beginning (step # 9).
And # 10), an image is recorded in the index image recording area (step # 11).

In the case of this method, the index image can be freely selected. Further, when an image is selected, by recording a signal indicating an index in the subcode area, it is possible to perform cueing based on this signal.

The display method of the index image on the monitor in the first and second embodiments is preferably a multi-screen in which the index image is reduced and a plurality of index images are displayed on one screen. A high-frequency component is unnecessary for a reduced image, and in the present invention, a DCT code-compressed DC component and a low-frequency component are extracted, which is suitable for producing a reduced image.

Creation of a multi-screen can be easily realized by recording the thinned-out image data on a tape.
Further, it is also possible to display the thinned-out image data on the monitor via the memory 11 and the image expansion means 12 without recording on the tape.

[0039]

As described above, according to the first aspect, the index images are collected and recorded in the preliminarily provided blank area at the beginning of the tape. Therefore, by reproducing this index image, It is possible to instantly know what is recorded on the tape.

According to the second aspect, the index start signal is recorded every time the recording is started, and the index image can be automatically stored in the memory when the tape is rewound or fast forwarded. Index images can be extracted.

Furthermore, from the third viewpoint, the index image automatically extracted is recorded in the blank area of the tape from the IC memory, so that the index image can be stored more reliably.

By extracting only the DC or low-frequency component image signal from the image data, a reduced screen can be created without increasing the circuit scale, and a multi-screen display of index images can be easily achieved. (Claim 4).

Further, by integrating the above, a plurality of index images are automatically recorded as multi-images in the blank area of the tape, so that the contents recorded on the tape can be easily known at the time of tape reproduction. Yes (Claim 5).

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing tracks recorded on a tape.

FIG. 3 is an explanatory diagram showing a track pattern area.

FIG. 4 is a flowchart showing a first embodiment.

FIG. 5 is a flowchart showing a second embodiment.

[Explanation of symbols]

5, 8 and 11 memory 12 image decompression means 13 subcode detection means 14 control means 15 index memory (index storage means) 16 recording means

Claims (5)

[Claims] 1. An index storage unit for preliminarily defining a blank area at least at the beginning of a video tape to store image data extracted for each scene, and the stored image data in the blank area. A digital video tape recorder, comprising: a recording means for recording. 2. A digital video tape recorder having a sub-code area for recording an auxiliary control signal in a part of a track of a video tape and comprising auxiliary control signal recording means for recording the auxiliary control signal, comprising: ) Sub-code detection means for detecting the index start signal recorded for each scene by the auxiliary control signal recording means,
(b) When the index start signal is detected during high-speed operation of rewinding or fast-forwarding the video tape, a control means for extracting image data where the index start signal is recorded, and (c) extracting A storage means for index for storing the image data thus obtained, and a digital video tape recorder. 3. A digital video tape recorder having the features of both claim 1 and claim 2. 4. The digital video tape recorder according to claim 2, wherein the control means extracts only the data of the DC component and the low frequency component from the compressed image data. 5. The digital video tape recorder according to claim 4, which has the features of claim 3.