JPH0779489B2 - Image compression recording method - Google Patents

Description

TECHNICAL FIELD The present invention relates to an image compression recording system that enables rotational reproduction of a stereoscopic image.

[Prior Art] Images obtained by simultaneously capturing images of two video cameras at the positions of both eyes of a human being are alternately recorded on a recording track of an electrostatic capacity type disc, and a left-eye dedicated image and a right-eye dedicated image are recorded. By alternately playing the image of, and viewing the reproduced image alternately with the left eye and the right eye through the stereoscopic scope with a liquid crystal shutter,
A stereoscopic image reproduction system for reproducing a stereoscopic image is known. This type of stereoscopic image reproduction system reproduces a stereoscopic image using binocular parallax, but unlike the case of a planar image, it has the same capacity for recording left-eye and right-eye video signals. With a recording medium, it can record only about half the signal that would be recorded with a normal video signal, which makes it unsuitable for long-term video software recording, and stereoscopic playback is not possible without a stereoscope. Therefore, there is a problem that it is not suitable for a large number of people to view a stereoscopic image at the same time.

By the way, there is a high-efficiency coding method that is in the limelight in recording a large amount of image data on a recording medium having a relatively small recording capacity. This method is a method of compressing by subtracting a prediction value predicted using data of one frame before from image data regarding pixels in an XY two-dimensional image plane and encoding the difference as prediction error data. . In general, since the prediction error data can be approximated by a Laplace distribution, in the conventional compressed image data recording / reproducing system 1 shown in FIG. 4, the quantizing circuit 3 in the encoder 2 used in the recording system is nonlinear by logarithmic compression. A quantizer circuit is used. The encoder 2 supplies the input image data to the quantization circuit 3 via a subtracter 4 that takes the difference from its predicted value. The prediction error data converted from the level value to the level number in the quantization circuit 3 is converted into an unequal-length code in the code conversion circuit 5 and recorded in the CD-ROM 6, while being transmitted via the local decoder 7. It is fed back to the subtractor 4. The local decoder 7 outputs the output of the inverse quantization circuit 8 for inverse processing of the quantization, that is, the inverse conversion of the level number into the level value, via the predictor 9 and the subtractor 4
While being fed back to the adder 10 provided on the input side of the predictor 9.

On the other hand, the decoder 12 for decoding the prediction error data read from the CD-ROM 6 is a code inverse conversion circuit for converting the prediction error data code-converted by the unequal length coding into the equal-length code by the inverse conversion. 13, an inverse quantization circuit 14 that inversely quantizes the output of the code inverse conversion circuit 13, an adder 15 and a predictor 16 that form image data from the output prediction error data of the inverse quantization circuit 14.
Consists of. The output of the inverse quantization circuit 14 is output via the adder 15 and is positively fed back to the adder 15 via the predictor 16, and the image data is reproduced by the cyclic addition of the prediction error data and its decoded output. It

[Problems to be Solved by the Invention] In the conventional compressed image data recording / reproducing system 1,
For example, in order to use the CD-ROM 6 as a catalog recording medium for sale on paper, when trying to compress and record the stereoscopic image data of the products handled, two video cameras are used for each product and the image signal dedicated to the left eye and the image signal dedicated to the right eye are used. It is necessary to pick up the image and record the prediction error data obtained by compressing these image signals by predictive coding alternately on the left and right on the CD-ROM6. Alternate recording of the prediction error data had problems such as a considerable amount of labor and time.

Also, the CD-ROM 6 recording the left and right prediction error data, when decoded by the same method as reproducing the planar image data,
Image data for the left eye only and the right eye only, which makes sense only after being reproduced independently of each other, are mixed and reproduced by a single predictor 16, and as a result, the viewpoint cannot be localized, not to mention with the naked eye. Even when wearing a stereoscopic scope, there was the problem that even stereoscopic images, not even stereoscopic images, could be viewed.

[Means for Solving Problems] The present invention has been made to solve the above problems, in which a front image of a subject is compressed by intra-image predictive coding, and the same subject is copied from different angles one after another. It is characterized in that the obtained image is sequentially compressed by the image unit time predictive coding, and the prediction error data obtained by the series of compression is recorded in cascade.

[Operation] According to the present invention, a front image of a subject is compressed by intra-image predictive coding, and images obtained by successively photographing the same subject from different angles are sequentially compressed by inter-image-unit predictive coding to obtain a series of images. By recording the prediction error data obtained by the compression of (3) in cascade, the stereoscopic image can be rotated and reproduced.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 is a system configuration diagram showing an embodiment of an image compression recording system to which the image compression recording system of the present invention is applied, and FIG. 2 is a CD-RO shown in FIG.
FIG. 3 shows an example of data contents recorded in M,
It is a system block diagram which shows one Example of the compressed image reproduction system which reproduces | regenerates the same CD-ROM.

In FIG. 1, the image compression / recording system 21 images, for example, a product to be published in a product catalog or the like by using a single video camera 22 in order from the front image at different angles, and captures the imaged signal as an intra-frame correlation. The structure is such that the data is recorded on the CD-ROM 6 while sequentially predictive-encoding using the inter-frame correlation. Since the front image is compressed by intraframe predictive coding, and the subsequent image is compressed by interframe predictive coding, the intraframe prediction circuit 25 and the interframe prediction circuit 26 are used as predictors 24 in the encoder 23 on both sides. Switch to
The ones connected in parallel via 27 and 28 are used. 29
Switch 2 between the front image and the other images.
This is an encoding control circuit that switches between 7,28.

By the way, the front image V _{1 of the} subject is encoded according to the intra-frame prediction mode, and intra-frame prediction error data E ′ (V ₁ ) with a dash is generated. Then, the second image V ₂ following the front image V ₁ was in accordance with the prediction mode between frames, the difference V ₂ -V ₁ between front image V _1, is generated as inter-frame predictive error data E (V ₂₎ . Below, the third image V ₃
Also, V ₃ −V ₂ is the inter-frame prediction error data E
Prediction error data up to E (V ₈ ) is generated such as (V ₃ ). Finally, the inter-frame prediction error data E
A series of image compression is completed by generating (V ₁ ) = V ₈ −V ₁ .

Therefore, as shown in FIG. 2, the CD-ROM 6 starts with the intra-frame prediction error data E '(V ₁ ) and the inter-frame prediction error data E (V ₂ ) to E (V ₈ ), E. (V ₁ ) will be recorded in tandem. It should be noted that each prediction error data is accompanied by data indicating the prediction mode used for the generation.

On the other hand, a compressed image reproduction system 30 for reproducing the CD-ROM 6
Matches the encoder 23, and as the predictor 32 in the decoder 31,
The intra-frame prediction circuit 33 and the inter-frame prediction circuit 34 are connected in parallel with the change-over switches 35 and 36 before and after the circuit. A decoding control circuit 37 controls the predictor 32, detects data indicating the different prediction modes read from the CD-ROM 23, and controls the changeover switches 35 and 36 according to the detected data. That is, the decoder 31
When the intra-frame prediction error data E (V ₁ ) is supplied to the intra-frame prediction circuit 3
3 side, and when the inter-frame prediction error data is supplied to the decoder 31, the changeover switches 35, 36
To the inter-frame prediction circuit 34 side.

By the way, in this embodiment, since a stereoscopic image is reproduced using the stereoscopic scope 40 with a liquid crystal shutter, an image memory 41 capable of storing a frame image is connected to the output side of the predictor 32, and the image memory 41 and the frame The predicting circuit 34 and the predicting circuit 34 are connected to the image receiver 43 via a changeover switch 42 which works in conjunction with the liquid crystal shutter. Therefore, as the image decoded by the decoder 31, two images with different imaging angles are alternately reproduced, and by mounting the stereoscopic scope 40, a stereoscopic image using binocular parallax is viewed. be able to. At the same time, as the playback of the CD-ROM 23 progresses, the imaging angle of the subject also gradually changes, so the played stereoscopic image rotates, which allows the catalog products to be displayed all around without any special operation. Can be observed.

As described above, according to the image compression / recording system 21, the front image of the subject is compressed by intraframe predictive coding, and the images obtained by sequentially photographing the same subject from different angles are sequentially predicted by interframe predictive coding. Since the prediction error data obtained by compressing and compressing a series of data is recorded on the CD-ROM 6 in cascade, the left-eye-only image signal and the right-eye-only image signal separately captured by two video cameras are used. It is possible to obtain the prediction error data necessary for reproducing a stereoscopic image using a single video camera 22, and to record such prediction error data without using a complicated method such as predictive coding and then alternately recording. The CD-ROM 6 can rotate and reproduce a stereoscopic image if the decoder 31 having the two prediction circuits 33 and 34 and the stereoscopic scope 40 with a liquid crystal shutter are provided.

In the above embodiment, the compressed image reproduction system 30
Requires an image memory 41 in addition to the predictor 32, but even the conventional decoder 12 can rotate and reproduce a planar image without using the stereoscopic scope 40.

Further, the data recording medium is not limited to the CD-ROM 6, but may be another magnetic recording medium such as a magnetic disk or a magnetic tape.

EFFECTS OF THE INVENTION As described above, according to the present invention, a front image of a subject is compressed by intra-image-unit predictive coding, and further images obtained by shooting the same subject from different angles are sequentially displayed between image units. By compressing by predictive coding and predictively recording the prediction error data obtained by a series of compressions in tandem, the left-eye-only image signal and the right-eye-only image signal captured separately by using two video cameras, Prediction error data required for stereoscopic image reproduction can be obtained by using a single video camera without relying on a complicated method such as predictive coding and then alternate recording, and image recording recording such prediction error data is possible. From the medium, if there is a decoder with two prediction circuits and a stereoscope with a liquid crystal shutter, it is possible to rotate and reproduce stereoscopic images. Even if there is a flat image, it has an excellent effect that the object can be rotated and reproduced while being a flat image.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing an embodiment of an image compression recording system to which an image compression recording system of the present invention is applied,
FIG. 2 is a diagram showing an example of data contents recorded on the CD-ROM shown in FIG. 1, and FIG. 3 is a system configuration showing an embodiment of a compressed image reproducing system for reproducing the CD-ROM. FIG. 4 is a system configuration diagram showing an example of a conventional compressed image data recording / reproducing system. 6 ... CD-ROM, 21 ... Image compression recording system, 22 ... Video camera, 23 ... Encoder, 24 ... Predictor, 25 ... Intra-frame prediction circuit, 26 ... Inter-frame prediction circuit, 27 , 28 ... Changeover switch, 29 ... Encoding control circuit.

Claims (1)

[Claims] 1. A front image of a subject is compressed by intra-image predictive coding, and images obtained by successively photographing the same subject from different angles are sequentially compressed by inter-image-unit predictive coding, and a series of compressions are performed. An image compression recording method characterized in that the prediction error data obtained by the method is recorded in a column.