|Publication number||USRE41200 E1|
|Application number||US 09/075,666|
|Publication date||Apr 6, 2010|
|Priority date||May 22, 1992|
|Also published as||DE69316440D1, DE69316440T2, DE69333103D1, DE69333103T2, DE69334278D1, DE69334280D1, EP0571180A2, EP0571180A3, EP0571180B1, EP0782340A2, EP0782340A3, EP0782340B1, EP1331817A1, EP1331817B1, EP1335598A1, EP1335598B1, US5517588|
|Publication number||075666, 09075666, US RE41200 E1, US RE41200E1, US-E1-RE41200, USRE41200 E1, USRE41200E1|
|Original Assignee||Sony Corporation|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (22), Non-Patent Citations (14), Classifications (33)|
|External Links: USPTO, USPTO Assignment, Espacenet|
1. Field of the Invention
This invention relates to a digital data conversion equipment and a method for the same, which are applicable to an interpolation of a thinned picture element in data conversion, up-conversion for converting a television signal with standard resolution into a television signal with high resolution and so on.
2. Description of the Prior Art
There are generally two kinds of systems for converting a digital video signal. One of them is a system for converting a signal whose resolution is high with respect to the space or time or a signal having a large amount of information into a signal of a low resolution. The other is a system for converting, on the contrary, a signal whose resolution is low with regard to the space or time or a signal having a small amount of information signal of a high resolution.
In the former case, a signal having inherently a large information amount is converted into a signal of a small information amount. For example, by properly thinning out a picture element information amount or field/frame information, a signal of a low space/time resolution can be easily formed.
The above example relates to what is called a down converter to, for instance, convert a video signal of a high definition (HD) system into a video signal of a standard definition (SD) system. Various kinds of techniques have already been proposed.
The latter case relates to up conversion to, for example, convert a video signal of the SD system to a video signal of the HD system. An example in which an electronic zooming process is executed or an enlargement of an image is performed is considered. In those examples, hitherto, information which inherently lacks is interpolated by using an interpolation filter and the interpolated information is used.
As still another example, there is a sub-sampling method for periodically thinning out pixel data in order to compress a recording/transmission data amount in the case where a capacity of the recording/transmitting system is limited. In this case, the images thinned out are interpolated on the reproducing/receiving side by using an interpolation filter.
However, there is a problem that the resolution of an output picture obtained by interpolation with a filter is degraded. For example, even if a HD television signal is formed by interpolating a SD video signal by a filter, an HD component (high frequency component) which is not present in an input SD signal is not reproduced. As a result, the spatial resolution of an output picture is lowered.
An object of the invention is to provide digital data conversion equipment and a method for the same capable of reproducing a high resolution component.
According to an aspect of the present invention, there is provided a digital data conversion equipment, comprising:
According to another aspect of the present invention, there is provided a digital data conversion method, comprising:
The above, and other, objects, features and advantage of the present invention will become readily apparent from the following detailed description thereof which is to be read in connection with the accompanying drawings.
Hereunder, one embodiment of this invention will be explained. This one embodiment transmits thinned and compressed data and reproduces a thinned picture element on the reception side.
Input digital video data is supplied to a sampling circuit 2, and picture element data positioned alternately is thinned out in the horizontal direction. As shown in
The output data of the sampling circuit 2 is supplied to an encoder for highly efficient coding. For the highly efficient coding, orthogonal conversion coding such as DCT (Discrete Cosine Transform), ADRC (Dynamic Range Adaptive-type Coding) and so on, which are well known, can be adopted. With this encoder 3, the data amount to be transmitted is reduced.
The output data of the encoder 3 is fed to a transmission processing circuit 4. The transmission processing circuit 4 performs processing such as error correction coding, frame formation and channel coding. Transmission data is generated at an output terminal 5 of the transmission processing circuit 4. The transmission data is supplied through a transmission line 6. The transmission line 6 is limited to a communication line and includes processes of magnetic recording and reproduction in its meaning.
Reception data is fed through an input terminal 7 to a reception processing circuit 8. The reception processing circuit 8 performs processing such as decoding of channel coding, frame decomposition, and error correction. The output of the reception processing circuit 8 is supplied to a decoder 9 for highly efficient coding. The decoded output of the decoder 9 is supplied to a selecting circuit 10 and a simultaneous output circuit 11.
The simultaneous output circuit 11, as shown in
A mapping table for data conversion formed in a manner mentioned later is stored in the memory 13. In this example, a mapping table including plural parameters is stored in the memory 13. A parameter read out from an address corresponding to the output data of the clustering circuit 12 is supplied to the interpolation data generating circuit. The interpolation data generating circuit 14 provides interpolation data x by the calculation of:
using transmission picture element data a, b, c, and d from the simultaneous output circuit 11 and parameters w1, w2, w3, and w4 from the memory 14.
The interpolated data x is supplied to the selecting circuit 10. The selecting circuit 10 selects the output of the decoder 9 when a transmission picture element is present, while the selecting circuit 10 selects interpolated data from the interpolation data generating circuit 14 at a position of a thinned picture element. Consequently, decoded video data corresponding to reception data is provided at an output terminal 15 of the selecting circuit 10.
A mapping table formed in advance by training is stored in the memory 13.
The clustering circuit 24 carries out the clustering picture element data to generate class information as the clustering circuit 12 of
The output of the clustering circuit 24 is given to one input terminal 25a of a switching circuit 25. The output of a counter 26 is supplied to the other input terminal 25b of the switching circuit 25. The counter 26 generates addresses, which sequentially change, by counting clock CK. The output of the switching circuit 25 is supplied to the data memory 23 and a memory 28 for parameters as their addresses.
Sample values of picture element a, b, c, d, and x are written into the data memory 23 with respect to addresses which are class information. For example, (a10, a20, . . . , an0) with respect to the picture element data a, (b10, b20, . . . , bn0) as to the picture element data b, (c10, c20, . . . , cn0) with respect to the picture element data c, and (d10, d20, . . . , dn0) as to the picture element data d are stored in a certain address AD0 of the data memory 23. As for other addresses from the clustering circuit 24, picture element data is stored in the memory 23 similarly.
Next, the switching circuit 25 is switched from the input terminal 25a to 25b, and the content of the data memory 23 is sequentially read out by an address from the counter 26. The read-out of the data memory 23 is supplied to an arithmetic circuit 27 of the least square method. With this minimum square method, parameters w1 to w4 are obtained with minimum error.
When attention is paid to one address, the following simultaneous equations are established with respect to this address:
Now, since x1 to xn, a1 to an, b1 to bn, c1 to cn, and d1 to dn are known in advance, the parameters w1 to w4 are obtained so that the square of the error for x1 to xn (actual values) is minimized. This applies to other addresses.
The parameters w1 to w4 obtained at the arithmetic circuit 27 are written into a memory 28. A mapping table which has been written into the memory 28 is stored in the memory 13 of FIG. 1. Therefore, the value of x, which is a thinned picture element, is produced at the interpolation data generating circuit 14 using the parameters produced from the memory 13.
For the mapping table, not only the above-stated parameters but also the one from which output data values themselves are provided may be employed. In this case, the interpolation data generating circuit 14 in
The read-out output of the frequency memory 31 is supplied to an adder 32 and added by +1. The output of the adder 32 is written into the same address of the memory 31. For the memories 30 and 31, each content of their addresses is cleared at zero as the initial stage.
Data read from the data memory 30 is supplied to a multiplier 33 and multiplied by a frequency which is read out of the frequency memory 31. The output of the multiplier 33 is given to an adder 34 and added to the input data x there. The output of the adder 34 is supplied to a divider 35 as a dividend. To the divider 35, the output of the adder 32 is fed as a divisor. The output of the divider 35 (quotient) becomes input data of the data memory 30.
In the above-mentioned structure of
By carrying out the above-mentioned operation within a determined period, a mapping table is stored into the memory 30 so that data, which is present at that time, is output when a class is designated by the output of the clustering circuit. In other words, when plural picture element data of an input video signal is given, a mapping table can be formed so that data is output to correspond to its clustered data on the average.
Another embodiment of the invention shown in
The read-out outputs of the memories 44a to 44d are given to a selector 45. The selector 45 is controlled by the output of a selection signal generating circuit 46. A sampling clock of the HD picture is supplied from an input terminal 47 to the selection signal generating circuit 46. The four picture element data y1 to y4 is selected sequentially by the selector 45 and is supplied to a scanning conversion circuit 48. The scanning conversion circuit 48 generates picture element data of the HD picture in the order of raster scanning at an output terminal 49. A monitor for HD is connected to the output terminal 49 through a D/A converter (not shown). The number of picture elements of an output picture is four times that of picture elements of an input SD video signal.
The HD video signal is supplied to a simultaneous output circuit 52. The simultaneous output circuit 52 simultaneously produces picture element data a to 1 and y1 to y4 having a relationship in positions shown in FIG. 6. The picture element data a to 1 is supplied to a clustering circuit 53. The clustering circuit 53 performs the classification of gradation, patterns, etc., as in the above-mentioned one embodiment. The output of the clustering circuit 53 is commonly given to mapping table generating circuits 54a to 54d.
The picture element data y1 to y4 is supplied to the mapping table generating circuits 54a to 54d which have the same construction. The one similar to the structure for obtaining average value as shown in
Mapping tables showing the correlation between the HD video signal and the SD video signal are stored in the mapping table generating circuits 54a to 54d. In other words, when plural data of the SD video signal is given, a mapping table, which outputs picture element data of the HD video signal on the average corresponding to the one provided by clustering these a plural data, can be formed. This mapping table is stored in the memories 44a to 44d with the structure of FIG. 5.
Although the above-mentioned one embodiment is an example where the up-conversion of the SD video signal to the HD video signal is made, the invention can be applied similarly to the enlargement of a picture, besides this embodiment.
According to the invention, data transmitted with a thinning-out system can be received, and a thinned picture element can be interpolated without the deterioration of resolution. When picture element data lacking at the time of picture element enlargement is interpolated, the invention is applicable in a similar manner. Also, the invention not only permits a video signal with standard resolution to be converted to that with high resolution but also allows a picture with high resolution to be displayed on a monitor.
Having described specific preferred embodiments of the present invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or the spirit of the invention as defined in the appended claims.
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|U.S. Classification||382/300, 348/445|
|International Classification||H04N19/423, H04N19/98, H04N19/59, H04N19/625, H04N19/65, H04N7/46, G09G5/00, H04N5/228, G09G5/36, H04N7/28, G06T3/40, H04N7/00, H04N19/00, G06K9/03, H04N7/01|
|Cooperative Classification||H04N19/94, H04N19/98, H04N19/60, H04N19/154, H04N19/59, G06T3/4007, H04N7/0145, H04N7/0125|
|European Classification||H04N7/01T6, G06T3/40B, H04N7/26A6Q, H04N7/30E7, H04N7/28, H04N7/26Z2, H04N7/01H, H04N7/46S|