JPH0583673A - Picture recording and reproducing device - Google Patents

Abstract

PURPOSE:To enable the recording and reproduction of a still picture as well as a moving image and to improve the reliability at a still picture recording even when the picture data having the deep depth of one picture element data in the picture recording an reproducing device. CONSTITUTION:An error detection code addition circuit 13 adding a code to detect an erroneous code at the time of recording picture data in the data area storing picture element data divided by a divider circuit 7 is provided at the poststage of the divider circuit 7. An error detection circuit 14 detecting whether or not an erroneous code is generated in a picture element to be synthesized to picture element data with the original bit number in the following synthesis circuit 8 by a code added in the error detection code addition circuit 13 for picture element data corrected by the decoding circuit 5 at the time of reproduction is provided at the poststage of a decoding circuit 5. By the operation of the error detection code addition circuit 13 and the error detection circuit 14, the reliability at the time of recording a still picture can be improved even the picture data having the deep depth of one picture element data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to image recording / reproducing such as a digital video tape recorder (hereinafter abbreviated as "digital VTR") for inputting and recording digital image data or image data obtained by digitizing video signals. More particularly, the present invention relates to an image recording / reproducing apparatus capable of recording / reproducing not only a moving image but also a still image and improving reliability in recording a still image even for image data having a large data depth of one pixel.

[0002]

2. Description of the Related Art In recent years, due to the progress of digital technology, in an image recording / reproducing apparatus, a digital VTR for digitizing a video signal of a television and recording / reproducing on a magnetic tape with high image quality is being developed. Such a digital VTR 1 is, for example, as shown in FIG. 3, an A / D converter 2 for digitizing a video signal input from another image device and a digital VTR 1 from the A / D converter 2. A coding circuit 3 for inputting image data and adding an error correction code for correcting a coding error at the time of recording at the time of reproduction
And a data recording / reproducing section 4 for inputting the digital data to which the error correction code is added by the encoding circuit 3 to record and reproduce it on a recording medium such as a magnetic tape, and the digital data read from the data recording / reproducing section 4. A decoding circuit 5 for correcting a code error by the error correction code and outputting the corrected code;
The decoding circuit 5 comprises a D / A converter 6 for converting the digital data whose code error has been corrected into a video signal and outputting the video signal. Since such a digital VTR 1 digitally records a standard television signal in real time, the recording rate is extremely high at 80 to 100 megabits / second, and high density recording is performed. It has an encoding circuit 3 and a decoding circuit 5 for correction. However, since the recording density is high, even if error correction is performed by the above circuit, the error rate Er
Is That is, the error cannot be corrected at a rate of 1 bit per 10 ⁸ bits. At this time, in the case of a moving image in which the image contents appear to move, if the error rate Er is equal to or less than the above value, there is no visual problem.

On the other hand, it has begun to record still images by taking advantage of the large capacity of the digital VTR 1.
In this case, since the still image is different from the moving image in the data content for each image, the error rate Er is Then the reliability is low. That is, the error rate Er of a still image recording device using an optical disk or a magnetic disk as a recording medium is This is four orders of magnitude lower than that below.

The data depth of one pixel (bit depth)
With regard to the above, it has been said that there is no problem if 8 bits are used in a television signal, so the conventional digital VTR handles 1
The data depth of the pixel is 8 bits. But,
With the improvement in image quality of images, the data depth of one pixel is also increasing. For example, image data processing devices that handle image data of 10 to 12 bits have begun to appear. Therefore, such image data is recorded and reproduced. Digital VTRs are also emerging. Such a digital VTR 1'is, for example, as shown in FIG. 4, the A / D converter 2 and the encoding circuit 3.
And a dividing circuit 7 for inputting digital image data and dividing data having a data depth of 1 pixel larger than 8 bits (for example, 10 to 12 bits) into 2 pixel data. The image data from the decoding circuit 5 is input between the decoding circuit 5 and the D / A converter 6, and the data of the two pixels divided by the dividing circuit 7 are combined to form the original 10 to 12 bits. Synthesis circuit 8 for outputting as pixel data
Was provided.

[0005]

However, in the conventional digital VTR 1 shown in FIG. 3, when a still image is recorded by utilizing its large capacity, an optical disk or a magnetic disk is used as a recording medium. The error rate is lower than that of the still image recording apparatus by 4 digits, for example, and the reliability is low, so that it cannot be said to be sufficient as a still image recording apparatus. If the data depth of one pixel is as large as 10 to 12 bits, another conventional digital VTR 1'configured as shown in FIG. Although recording and reproducing were performed, the bit depth of the pixel data became large, so the occurrence of errors in the upper bits had a great impact on the image quality, and the reliability during still image recording was not sufficient. Met.

Therefore, the present invention addresses such a problem and is capable of recording and reproducing not only moving images but also still images.
An object of the present invention is to provide an image recording / reproducing apparatus capable of improving the reliability when recording a still image even for image data having a large data depth of one pixel.

[0007]

In order to achieve the above object, an image recording / reproducing apparatus according to the present invention inputs digital image data or image data obtained by digitizing a video signal, and a data depth of one pixel is predetermined. If the number of bits is larger than the number of bits, a dividing circuit for dividing the data into several pixel data, and a code for inputting image data from the dividing circuit and adding an error correction code for correcting a code error during recording during reproduction A circuit, a data recording / reproducing section for inputting digital data to which an error correction code is added by this encoding circuit to record and reproduce on a recording medium, and a code error of the digital data read from this data recording / reproducing section A decoding circuit that corrects with a code and the image data from this decoding circuit are input and the several pixel data divided by the above dividing circuit are combined to generate the original In image recording and reproducing apparatus comprising and a combining circuit for outputting a number of bits of the pixel data,
An error detection code addition circuit for adding a code for detecting a code error at the time of recording is provided in the remaining data area storing the several pixel data divided by the division circuit, and the decoding circuit is provided after the division circuit. In the subsequent stage of the circuit, a code added to the pixel data corrected by the decoding circuit at the time of reproduction by the code added by the error detection code adding circuit is added to the pixel to be combined with the pixel data of the original bit number in the subsequent combining circuit. An error detection circuit for detecting whether an error has occurred is provided.

[0008]

In the image recording / reproducing apparatus having the above-described structure, the error detection code adding circuit provided in the subsequent stage of the dividing circuit is used for recording in the remaining data area storing several pixel data divided by the dividing circuit. The code for adding the code for detecting the code error, and the code added by the error detection code addition circuit to the pixel data corrected by the decoding circuit at the time of reproduction by the error detection circuit provided in the subsequent stage of the decoding circuit. Thus, the subsequent synthesizing circuit operates so as to detect whether or not a code error has occurred in the pixel to be synthesized with the pixel data of the original bit number. As a result, even when the image data has a large data depth of one pixel, the reliability at the time of recording a still image can be improved.

[0009]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of an image recording / reproducing apparatus according to the present invention. The image recording / reproducing apparatus 10 inputs and records and reproduces digital image data or image data obtained by digitizing a video signal from an image device (not shown).
R, as shown in the figure, an A / D converter 2, a division circuit 7, an encoding circuit 3, a data recording / reproducing unit 4, a decoding circuit 5, a synthesizing circuit 8, and a D / A converter. 6, a manual input device 11, a controller 12, and an error detection code addition circuit 13 and an error detection circuit 14.

The A / D converter 2 digitizes a video signal V ₁ input from a television system (not shown) or the like and outputs image data. The division circuit 7 has a data depth of one pixel larger than a predetermined bit number with respect to the digital data output from the A / D converter 2 or the digital image data D ₁ input from a digital system (not shown). Is divided into several pixel data, and the processing is switched according to the data depth of one pixel by a control signal from the controller 12 described later. For example, depending on whether the data depth of one pixel is 8 bits or more, if it is 8 bits, it is output as it is, and the data depth of 8 bits or more (for example, 10 to 12 bits) In the case of having, the data is divided at 8 bits and output as 2 pixel data.

The coding circuit 3 adds an error correction code for correcting a coding error at the time of recording to the image data having a data depth of 8 bits inputted through the dividing circuit 7 at the time of reproducing. is there. The data recording / reproducing unit 4 inputs the digital data to which the error correction code has been added by the encoding circuit 3 and records and reproduces it on a recording medium such as a magnetic tape. The decoding circuit 5 corrects the code error of the 8-bit digital data read from the data recording / reproducing unit 4 by the error correction code added by the coding circuit 3.

Further, the synthesizing circuit 8 synthesizes the image data having the data depth of 8 bits inputted through the decoding circuit 5 with the several pixel data divided by the dividing circuit 7 to obtain the original bit. It is output as several pixel data, and the processing is switched according to the data depth of one pixel by a control signal from the controller 12 described later.
For example, depending on whether the data depth of one pixel is 8 bits or more, if it is 8 bits, it is output as it is and the data depth of 8 bits or more (for example, 10 bits or more) is output.
.About.12 bits), the two pixel data divided by the dividing circuit 7 are combined to output the original pixel data. Further, the D / A converter 6 converts the digital data synthesized by the synthesizing circuit 8 into a video signal V ₂ and sends it to a television system (not shown) or the like. The digital data synthesized by the synthesis circuit 8 may be directly sent to a digital system (not shown) as digital image data D ₂ without passing through the D / A converter 6.

The manual input device 11 allows the operator to manually input how many bits the data depth of one pixel of the image data to be handled is, and outputs a data depth determination signal. ing. Further, the controller 12 inputs the discrimination signal output from the manual input device 11, discriminates how many bits the data depth of one pixel is, and sends a control signal to the division circuit 7 and the synthesis circuit 8. And control them.

Here, in the present invention, an error detection code addition circuit 13 is provided between the division circuit 7 and the coding circuit 3, and an error detection circuit 14 is provided between the decoding circuit 5 and the synthesis circuit 8. Is provided. The error detection code addition circuit 13 adds a code for detecting a code error at the time of recording to the remaining data area in which several pixel data divided by the division circuit 7 are stored. For example,
When the data depth of one pixel is 8 bits or more, an error detection code for detecting a code error is added to an empty data area for the data divided into 2 pixels at 8 bits in the division circuit 7. It is supposed to do. This state will be described in more detail with reference to FIG.
FIG. 2 shows a case where the data depth of one pixel is 10 bits, and the 10-bit data of one pixel input as shown in FIG. _{0 to} D ₇ ) and a 2-bit portion (D ₈ , D ₉ ) and sent to the error detection code addition circuit 13 as 8 bits × 2 pixel data as shown in FIG. Then, of the 10-bit data for one pixel shown in FIG. 2A, the upper 2 bits (D ₈ and D ₉ ) as shown in FIG.
Error detection codes C _{0 to} C ₅ for detecting the occurrence of an error in the 10-bit data at the time of reproduction in the remaining empty area of the 8-bit 1-pixel data in which
(See the diagram on the right side of FIG. 1) is generated, stored, and output to the subsequent encoding circuit 3 shown in FIG. The error detection code adding circuit 13 is controlled by a control signal from the controller 12.

The error detecting circuit 14 uses the code added by the error detecting code adding circuit 13 to the pixel data corrected by the decoding circuit 5 at the time of reproducing the image so that the original bit number in the synthesizing circuit 8 is changed. This is to detect whether or not a code error has occurred in a pixel combined with pixel data. For example, when the data depth of one pixel of the pixel data corrected by the decoding circuit 5 is larger than 8 bits, as shown in FIG.
₈ and D ₉ ) are stored in the vacant area of 8-bit 1-pixel data, the error detection codes C _{0 to} C ₅ added by the error detection code adding circuit 13 cause the original number of bits of 10 bits in the synthesizing circuit 8. It is adapted to detect whether or not an error has occurred in the pixel data. The error detection circuit 14 is controlled by a control signal from the controller 12. Here, the synthesizing circuit 8 detects whether or not an error has occurred in the entire pixel data of the original bit number of 10 bits, but pay attention to the upper bits that greatly affect the image quality when the error occurs. Then, error detection can be performed.

[0016]

Since the present invention is constructed as described above,
An error detection code addition circuit 13 provided at the subsequent stage of the division circuit 7 adds a code for detecting a code error at the time of recording to the remaining data area in which several pixel data divided by the division circuit 7 are stored. In the error detection circuit 14 provided in the subsequent stage of the decoding circuit 5, the error detection code adding circuit 1 is added to the pixel data corrected by the decoding circuit 5 during reproduction.
With the code added in 3, it is possible to detect whether or not a code error has occurred in the pixel combined with the pixel data of the original bit number in the subsequent combining circuit 8. This allows
Even when the image data has a large data depth of one pixel, the reliability at the time of recording a still image can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an image recording / reproducing apparatus according to the present invention.

FIG. 2 is an explanatory diagram showing an operating state of an error detection code adding circuit.

FIG. 3 is a block diagram showing a digital VTR as an example of a conventional device.

FIG. 4 is a digital VTR as another example of a conventional device.
Block diagram showing

[Explanation of symbols]

 2 A / D converter 3 Encoding circuit 4 Data recording / reproducing unit 5 Decoding circuit 6 D / A converter 7 Dividing circuit 8 Compositing circuit 10 Image recording / reproducing device 13 Error detection code addition circuit 14 Error detection circuit

Claims (1)

[Claims] 1. A division circuit for inputting digital image data or image data obtained by digitizing a video signal and dividing the data having a data depth of one pixel larger than a predetermined number of bits into several pixel data. A code circuit for inputting image data from the dividing circuit and adding an error correction code for correcting a code error at the time of recording at the time of reproduction, and digital data to which the error correction code is added by this code circuit is inputted and recorded. A data recording / reproducing section for recording / reproducing on / from a medium, a decoding circuit for correcting a code error of digital data read from the data recording / reproducing section by the error correction code, and an image data from the decoding circuit for inputting the division circuit. Image reproducing apparatus having a synthesizing circuit for synthesizing several pixel data divided by Oite, downstream of the dividing circuit,
An error detection code adding circuit for adding a code for detecting a code error at the time of recording is provided in the remaining data area in which the several pixel data divided by the dividing circuit is stored, and a reproducing circuit is provided in the subsequent stage of the decoding circuit. Whether there is a code error in the pixel which is combined with the pixel data of the original bit number by the code added by the error detection code adding circuit to the pixel data corrected by the decoding circuit An image recording / reproducing apparatus comprising an error detection circuit for detecting the error.