JPH1175185A - Image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the capacity of a necessary image memory with no deterioration of picture quality after the conversion of scanning lines by dividing the video signals subjected to the thinning of scanning lines into plural frequency bands and then applying the processing accordant with the frequency bands to those divided video signals and storing them. SOLUTION: A conversion processing part 12 thins the scanning lines of video signals down to the number of scanning lines of the 2nd video signals. The thinned video signals are sent to a vertical wavelet conversion part 14. The part 14 filters the received video signals via an LPF 14a. Thus, a scanning line conversion device A performs the division of bands via the wavelet conversion when the number of scanning lines is converted and then applies the down sampling to the video signals of some bands to store them in an image memory 16. Therefore, the capacity of the memory 16 can be reduced while the deterioration of picture quality is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video processing device, and more particularly to a video processing device for converting the number of scanning lines.

[0002]

2. Description of the Related Art Conventionally, a scanning line converter for converting the number of scanning lines of a video signal has been known. That is, the scanning line conversion device receives the first video signal, and outputs the second video signal having the different number of scanning lines.
Is converted into a video signal. Here, a description will be given of a conventional scanning line conversion device, which is configured as shown in FIG. That is, the scanning line conversion device includes an input processing unit 110, a vertical filter unit 112, an image memory 114
And an output processing unit 116.

[0003] The input processing unit 110 is used to input the first input data.
Is converted into a format in which video signal processing can be performed inside the apparatus. The vertical filter unit 112 performs a low-pass vertical filter process on an input video signal in order to suppress deterioration in image quality at the time of scanning line conversion. Further, the image memory 114 is a memory capable of storing at least one screen of the second video signal, and the writing and reading are operated asynchronously. Further, the output processing unit 116 converts a video signal format inside the device into a second video signal format.

In the scanning line converter having the above-described configuration, the first video signal is input to the input processing unit 110. Then, in the input processing unit 110, the first video signal is converted into a signal format suitable for processing inside the device, for example, into a digitized luminance signal and two color difference signals. Next, the vertical filter unit 112 performs a vertical filter process on the luminance signal and the color difference signal.
That is, the addition processing is performed after multiplying each of the N lines by a predetermined weighting coefficient.

[0005] The video signal subjected to the vertical filter processing is
After the number of scanning lines is converted so as to match the number of scanning lines of the second video signal, the data is written to the image memory 114 in synchronization with the clock of the first video signal. Here, the conversion of the number of scanning lines is performed by, for example, a memory write enable signal composed of a comb-shaped pulse signal.
Is performed by controlling the writing to.

Then, the video signal written in the image memory 114 is read out in synchronization with the clock on the second video signal side. The read-out luminance signal and color difference signal are converted into a video signal suitable for the format of the second video signal in the output processing unit 116, and output as the second video signal.

[0007]

However, according to the above-described conventional scanning line conversion apparatus, at least one screen is required to convert the first video signal into the second video signal while suppressing loss and deterioration of the first video signal. An image memory capable of storing video signals for every minute was required. That is, an image memory having a capacity of at least one field or one frame is required. Therefore, as the pixel information of the second video signal increases,
There is a problem that the required capacity of the image memory increases. Accordingly, it is an object of the present invention to provide a scanning line conversion device capable of reducing the required capacity of an image memory without deteriorating the image quality after scanning line conversion.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a first object of the present invention is to provide a video processing apparatus for converting a scanning line of a video signal, comprising: A conversion processing unit that performs a scanning line thinning process on the video signal, a band dividing unit that divides the decimated video signal into a plurality of frequency bands, and a video signal that is band-divided by the band dividing unit. On the other hand, it is characterized by having processing means for performing processing according to the frequency band, and storage means for storing the video signal processed by the processing means.

Therefore, if the processing for reducing the signal rate of the band-divided video signal is performed and stored in the storage means, the capacity of, for example, an image memory in the storage means can be reduced. In addition, since band division is performed, if the low-frequency component is weighted more than the high-frequency component and stored in the storage unit, the deterioration of the image quality can be reduced.

Second, in the first configuration, the band division by the band dividing means is performed by wavelet transform. Thirdly, in the first or second configuration, the processing unit discards a video signal of a high frequency component. Therefore, since the low-frequency components are stored in the storage unit and the processing is performed, the deterioration of the image quality can be reduced.

Fourthly, in the third configuration, the processing means performs a process of reducing a signal rate of a video signal which has not been discarded, and the video processing device further stores the video signal from the storage means. It is characterized by having a restoring means for restoring the signal rate of the read video signal. Thus, since the storage is performed while reducing the signal rate of the video signal, the capacity of the storage unit can be reduced. Fifth, in the fourth configuration, the video processing device further includes a filter processing unit that performs a filter process on the video signal whose signal rate has been restored. Performing this filter processing can reduce deterioration in image quality.

Sixth, in the first or second configuration, the processing means performs quantization on the video signal in accordance with a quantization table having a quantization step smaller as the frequency component becomes lower. Wherein the video processing device further comprises inverse quantization means for performing inverse quantization on the video signal of each frequency band read from the storage means according to the same quantization table as used in quantization. And Accordingly, since the quantization step is made finer and stored in the storage means as the frequency becomes lower, the deterioration of the image quality can be reduced and the capacity of the storage means can be reduced. Further, since the high-frequency side is also taken into account when outputting, the image quality can be improved. Seventh, the sixth
In the configuration of the above, the processing means performs a process of reducing the signal rate of the video signal, the video processing device further restores the signal rate of the video signal from the inverse quantization means, and a plurality of frequency bands And a synthesizing means for synthesizing the video signals. Thus, since the storage is performed while reducing the signal rate of the video signal, the capacity of the storage unit can be reduced.

Eighthly, in the above-mentioned seventh configuration, the synthesizing means includes a filter processing means for performing a filtering process on the video signal whose signal rate has been restored. Ninth, the seventh or the eighth
Is characterized in that the combining by the combining means is performed by inverse wavelet transform.

In a tenth aspect, there is provided a video processing apparatus for converting a scanning line of a video signal, wherein the conversion processing means performs a thinning process on the scanning line for the video signal to be converted, and a video processing device which performs the thinning process. Band extracting means for extracting a video signal of one or a plurality of frequency bands from a signal; signal rate reducing means for reducing a signal rate of the video signal extracted by the band extracting means; Storage means for storing a video signal stored in the storage means, a signal rate restoring means for reading out the video signal stored in the storage means and restoring a signal rate, and a filter for performing a filtering process on the video signal having the restored signal rate Processing means;
It is characterized by having. Therefore, the capacity of the storage unit can be reduced by extracting the low-frequency component and storing the data in the storage unit after reducing the signal rate. In the video information stored in the storage unit, the signal rate is restored by the signal rate restoration unit, and the filtering process is performed, so that the deterioration of the image quality can be reduced. Eleventh, in the tenth configuration, the extraction by the band extracting unit is performed by wavelet transform, and the filtering unit is performed by inverse wavelet transform.

In a twelfth aspect, there is provided a video processing apparatus for converting a scanning line of a video signal, which comprises a conversion processing unit for thinning out a scanning line for a video signal to be converted, and a wavelet conversion unit. , A wavelet transform having a low-pass filter that performs low-pass filtering on a video signal that has undergone decimation processing, and a downsampler that reduces the signal rate of the video signal that has been subjected to low-pass filtering Means, storage means for storing the video signal from the wavelet conversion means, wavelet inverse conversion means, an upsampler for restoring the signal rate of the video signal stored in the storage means, And a wavelet inverse transform means having a low-pass filter for performing low-pass filtering on the restored video signal. That. In the video processing device having the twelfth configuration, the conversion processing means performs a thinning process on the video signal. Then, a filtering process is performed by a low-pass filter of the wavelet transform unit, a signal rate is reduced by a downsampler, and the signal is stored in the storage unit. Further, in the upsampler of the above-mentioned wavelet inverse transform means, the restoration of the signal rate is performed, and thereafter, the filter processing is performed by the low-pass filter. Therefore, the filtered video signal is down-sampled and stored in the storage means, so that the capacity of the storage means can be reduced and deterioration of the video signal can be reduced.

In a thirteenth aspect, there is provided a video processing apparatus for converting a scanning line of a video signal, comprising a conversion processing means for thinning out a scanning line for a video signal to be converted, and a wavelet conversion means. A low-pass filter that performs low-pass filtering on the decimated video signal; a low-pass downsampler that reduces the signal rate of the video signal that has been subjected to the low-pass filtering; A high-pass filter that performs high-pass filtering on the processed video signal; and a high-frequency downsampler that reduces the signal rate of the video signal that has been subjected to high-pass filtering. A wavelet transforming means, and a quantizing means for quantizing a video signal from the wavelet transforming means, wherein the quantization is performed on the video signal from the low-frequency side downsampler. A quantizing unit, and a second quantizing unit that quantizes the video signal from the high-frequency side downsampler, wherein the quantization step of the first quantizing unit performs the quantization of the second quantizing unit. A quantization means set more finely than the quantization step, a storage means for storing the video signal from the wavelet conversion means, and a wavelet inverse conversion means, wherein the signal of the video signal stored in the storage means is provided. A low-pass upsampler for restoring a rate, a low-pass filter for performing low-pass filtering on a video signal whose signal rate has been restored by the low-pass upsampler, and a video signal stored in the storage means. A high-pass upsampler for restoring the signal rate of the high-pass filter, a high-pass filter for performing high-pass filtering on the video signal whose signal rate has been restored by the high-pass upsampler, And wavelet inverse transformation means and an addition means for adding the video signal from the video signal and the high pass filter from pass filter,
It is characterized by having.

In the video processing apparatus having the thirteenth configuration, the conversion processing means performs a thinning process on the video signal. Then, filter processing is performed by the low-pass filter of the wavelet transform unit, the signal rate is reduced by the low-frequency side downsampler, and the signal is sent to the first quantization unit of the quantization unit. The high-pass filter performs a filtering process, and the high-frequency side downsampler reduces the signal rate.
It is sent to the quantization unit. In the quantization means, the first
The quantization unit performs quantization on the video signal from the low frequency downsampler, while the second quantization unit performs quantization on the video signal from the high frequency downsampler. Note that the quantization step of the first quantization unit is set finer than the quantization step of the second quantization unit. Then, the quantized video signal is stored in the storage means. Then, in the wavelet inverse transform unit, the low-frequency-side upsampler restores the signal rate of the video signal stored in the storage unit, and further performs a filtering process using a low-pass filter. Further, the high-frequency-side upsampler restores the signal rate of the video signal stored in the storage means, and further performs a filtering process by a high-pass filter, and performs addition by an adding means. Therefore, according to the video processing apparatus of the thirteenth configuration, since the quantization step on the low frequency side is stored in the storage unit in a finer manner, the deterioration of the image quality can be reduced, and the capacity of the storage unit can be reduced. Can be.

A fourteenth feature is that, in any one of the first to thirteenth configurations, the division or extraction of the frequency band is performed in the vertical direction of the screen. Fifteenth, the fourth or fifth or seventh or eighth or first or
In the video processing device having the 0th or 11th or 12th or 13th configuration, line data composed of 0 data is inserted into the video signal when the signal rate is restored.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a scanning line conversion device A as a video processing device according to a first embodiment of the present invention includes an input processing unit 10 and a conversion processing unit 12.
And a vertical wavelet conversion unit 14 and an image memory 16
Vertical wavelet inverse transform unit 18 and output processing unit 2
0.

Here, the input processing unit 10 performs a predetermined process on the first video signal input to the input processing unit 10. That is, A / D conversion is performed on the input first video signal as a digital signal, and the first video signal is converted into a luminance Y signal and two color difference signals. Further, the conversion processing unit 12 as the conversion processing means performs a thinning process so that the video signal has the number of scanning lines of the second video signal. In other words, perform appropriate thinning processing for each horizontal line,
The predetermined number of scanning lines is set in the vertical direction. The conversion processing unit 12 is specifically configured as shown in FIG. 3, and includes one horizontal direction 1 in the video signal from the input processing unit 10.
When thinning out the video signal of the line, cutoff is performed. That is, in the horizontal period in which the thinning process is performed, the reading from the input processing unit 10 is not performed.

The vertical wavelet conversion unit 14 as the wavelet conversion means performs a vertical wavelet conversion. Specifically, as shown in FIG. 2, the vertical wavelet conversion unit 14 Sampler 14
b. This low-pass filter 14a
Is a low-pass filter used for wavelet transformation, and is specifically configured as shown in FIG.
That is, the low-pass filter 14a includes the line memories 141, 142, 143 and the multiplication units 151, 152,
153 and 154 and an adder 161 are provided.
Here, the line memories 141, 142, 143
It has the capacity to store data for one horizontal line,
This realizes a delay corresponding to one horizontal scanning line period of an input scanning line. Further, the multiplication units 151, 152, 15
Numerals 3 and 154 multiply each scanning line by a coefficient for weighting. The multiplication units 151, 152, 15
3, 154 filter coefficients are determined by selecting an appropriate mother wavelet so as to satisfy the orthogonal wavelet conversion condition. In addition, the addition unit 161 includes:
The outputs of the multipliers 151, 152, 153, and 154 are added. This low-pass filter 14a also functions as a band extracting unit.

The down sampler 14b serves to reduce the signal rate to one half, and converts the video signal for each horizontal line to the image memory 16b every other line.
To be stored. That is, the down sampler 14b is schematically shown in FIG. 4, and the signal is obtained by repeating conduction and interruption every other line, such as conducting in a certain horizontal period and cutting off in the next horizontal period. Reduce the rate by half. The down sampler 14b functions as the processing unit and the signal rate reducing unit.

The image memory 16 serving as the storage means stores a video signal, and writes the video signal from the vertical wavelet converter 14. In addition,
The writing to the image memory 16 is performed in synchronization with the clock of the first video signal, while the reading from the image memory 16 is performed with the clock synchronized with the second video signal. The image memory 16 is also used to adjust the clock frequency between one pixel.

The vertical wavelet inverse transform section 18 as the wavelet inverse transform means performs a vertical wavelet transform on the video signal read from the image memory 16, and specifically, As shown in FIG. 2, the upsampler 18a and the low-pass filter 18
b. This upsampler 18a
The signal rate of the video signal read from the image memory 16 is doubled.
In the video signal read out from the memory, 0 data for one line is input every other line in the horizontal direction. That is, the upsampler 18a is schematically shown in FIG. 5, in which the image is switched to the image memory 16 in a certain horizontal period, and is switched to the ground in the next horizontal period. The signal rate is doubled by switching between the memory 16 side and the ground side. The upsampler 18a functions as a signal rate restoring unit.

The low-pass filter 18b is a low-pass filter used for inverse wavelet transform. This low-pass filter 18b is also specifically shown in FIG.
It is configured as shown in FIG. The multiplication units 151, 1
The filter coefficients 52, 153, and 154 are determined by selecting an appropriate mother wavelet so as to satisfy the orthogonal wavelet conversion condition. Further, the output processing unit 20 converts the output from the vertical wavelet inverse transform unit 18 into a predetermined format of the second video signal and outputs it. That is, the video signal as a digital signal is
The signal is A-converted and output to the outside as a second video signal.

The vertical wavelet conversion unit 14
The vertical wavelet inverse transform unit 18 will be further described. When performing the vertical wavelet transform and the vertical wavelet inverse transform, the vertical wavelet transform unit 14 'and the vertical wavelet inverse transform as shown in FIG. The conversion unit 18 'is used.

That is, the vertical wavelet converter 1
4 ′ is a low-pass filter 14a and a down sampler 1
4b, a delay circuit 14c, and a high-pass filter 14d
And a down sampler 14e. Here, the delay circuit 14c delays the video signal by one line in the horizontal direction. Here, the delay circuit 14c is provided because the low frequency component from the downsampler 14b and the high frequency component from the downsampler 14e are alternately stored in the image memory 16, so that the high frequency side is This is to delay. The high-pass filter 1
Reference numeral 4d denotes a high-pass filter used for wavelet transformation, which is specifically configured as shown in FIG. However, the filter coefficient in the multiplication unit is set separately. Also, the down sampler 14e reduces the signal rate to half like the down sampler 14b.
It is to be. Note that the low-pass filter 14a,
The configuration of the downsampler 14b is the same as described above.

The vertical wavelet inverse transform unit 1
8 ′ is an upsampler 18a and a low-pass filter 1
8b, a delay circuit 18c, an upsampler 18d,
It has a high-pass filter 18e and an adder 18f. Here, the delay circuit 18c delays the video signal by one line in the horizontal direction. Here, the delay circuit 18c is provided because the video signal read from the image memory 16 is alternately read out of the low frequency component and the high frequency component, so that the addition unit 18f delays the addition. It is necessary to perform Also,
The upsampler 18d doubles the signal rate of the video signal read from the image memory 16. The high-pass filter 18e is a high-pass filter used for wavelet inverse transform, and is specifically configured as shown in FIG. However, the filter coefficient in the multiplication unit is set separately. Note that H ₀ (Z), H ₁ (Z), and F in FIG.
₀ (Z) and F ₁ (Z) are related by a predetermined relational expression.

The vertical wavelet transform unit 14 'and the vertical wavelet inverse transform unit 18' are configured as described above. In this embodiment, however, the high frequency components are reduced in order to reduce the capacity of the image memory. Because it will be discarded,
From the vertical wavelet converter 14 ', the delay circuit 1
4c, the high-pass filter 14d, and the downsampler 1
4e is omitted, and the vertical wavelet inverse transform unit 18 'is further provided with an upsampler 18d.
, The high-pass filter 18e and the adder 18f are omitted.

The operation of the scanning line converter A having the above configuration will be described. First, the first video signal is input to the input processing unit 10. Then, the input processing unit 10 performs A / D conversion on the input first video signal as a digital signal, and converts it into a luminance Y signal and two color difference signals. The input processing unit 10 sends the converted video signal to the conversion processing unit 12.

Next, the conversion processing section 12 performs a thinning process so that the video signal has the number of scanning lines of the second video signal. The video signal on which the thinning process has been performed is sent to the vertical wavelet converter 14. Next, in the vertical wavelet transform unit 14, filter processing is performed by the low-pass filter 14a. Then down sampler 14
b, the signal rate is halved and the image memory 16
Is output to Writing to the image memory 16 is performed in synchronization with the clock of the first video signal.

Next, the video signal stored in the image memory 16 is read out by the upsampler 18a. At this time, the video signal is read out from the image memory 16 in a certain horizontal period, and is read out in the next horizontal period. Image memory 1
6 is stopped. Then, in the next horizontal period, reading from the image memory 16 is performed again. That is, with reference to FIG. 5, in a certain horizontal period,
The video signal in the image memory 16 is read by switching to the image memory 16 side, and is switched to the ground side in the next horizontal period. During a period in which reading from the image memory 16 is stopped, 0 data is inserted. That is, in the video signal output from the upsampler 18a, line data composed of 0 data is inserted every other line. The reading from the image memory 16 is performed with a clock synchronized with the second video signal.

Next, the video signal output from the upsampler 18a is filtered by the low-pass filter 18b and output to the output processing unit 20. In the output processing section 20, the video signal is D / A converted and output to the outside as a second video signal.

As described above, according to the scanning line conversion apparatus A of this embodiment, when converting the number of scanning lines, band division is performed by wavelet conversion, and video signals in some of the bands are down-sampled. Is performed and stored in the image memory, so that the capacity of the image memory can be reduced while preventing the image quality from deteriorating. That is, in the case of the first embodiment, the capacity of the image memory can be reduced to half. In the above description, it has been described that the frequency band is divided into the high frequency component and the low frequency component. However, the present invention is not limited to this. is there. In that case, the lowest frequency component is stored in the image memory.

Next, a second embodiment will be described. Second
As shown in FIG. 8, the scanning line conversion apparatus B in the embodiment includes an input processing unit 60, a conversion processing unit 62, a vertical wavelet conversion unit 64, a quantization unit 66, an image memory 68, It has a quantization unit 70, a vertical wavelet inverse transformation unit 72, and an output processing unit 74.

Here, the input processing unit 60 performs the first
As in the embodiment, the first digital signal
A / D conversion is performed on the video signal of the image signal to convert it into a luminance Y signal and two color difference signals. The conversion processing unit 62 as the conversion processing means is configured in the same manner as in the first embodiment, and performs a thinning process so that the video signal has the number of scanning lines of the second video signal. In other words, appropriate thinning processing is performed for each line in the horizontal direction so that the predetermined number of scanning lines is set in the vertical direction.

The vertical wavelet conversion section 64 as the wavelet conversion means performs vertical wavelet conversion. Specifically, as shown in FIG. 9, a low-pass filter 64a, Down sampler 6
4b, a delay circuit 64c, and a high-pass filter 64d
And a down sampler 64e. That is, the vertical wavelet converter 64 has the same configuration as the vertical wavelet converter 14 '.

Here, the low-pass filter 64a includes:
This is a low-pass filter used for wavelet transform, and is configured in the same manner as the low-pass filter 14a of the first embodiment, and specifically, as shown in FIG. The down sampler 64b is for reducing the signal rate to one half as in the first embodiment, and stores the video signal for each horizontal line in the image memory 68 every other line. I do. That is, when the down sampler 64b is schematically shown, it is as shown in FIG. The delay circuit 64c delays the video signal by one line in the horizontal direction. Here, the delay circuit 64c
Is provided in order to store the low frequency components and the high frequency components in the image memory 68 alternately. The high-pass filter 64d is a high-pass filter used for wavelet transform, and is specifically configured as shown in FIG. The down sampler 64e reduces the signal rate to one half like the down sampler 64b.

The quantizing section 66 as the quantizing means performs a quantizing process, and has a first quantizing section 66a and a second quantizing section 66b as shown in FIG. ing. The first quantization unit 66a performs quantization by fine quantization steps, and the second quantization unit 6a
6b performs quantization by a coarse quantization step. That is, the first quantization unit 66a performs quantization using the first quantization table, and the second quantization unit 66b performs quantization using the second quantization table. The quantization step in the first quantization table is set more finely than the quantization step in the second quantization table. The downsamplers 64b and 64e and the quantization unit 66 also function as the processing unit. Further, the down sampler 64b functions as a low-frequency side down sampler,
The down sampler 64e functions as a high frequency side down sampler.

The image memory 68 stores a video signal, and writes the video signal from the quantization unit 66. The writing to the image memory 16 is performed by the first
The reading from the image memory 16 is performed with a clock synchronized with the second video signal. The inverse quantization unit 70 as the inverse quantization means performs an inverse quantization process. As shown in FIG. 9, the inverse quantization unit 70 includes a first inverse quantization unit 70a and a second inverse quantization unit 70b. Have. The first inverse quantization unit 70a performs inverse quantization using the first quantization table, and the second inverse quantization unit 70b performs inverse quantization using the second quantization table.

The vertical wavelet inverse transform section 72 as the wavelet inverse transform means performs vertical wavelet transform on the video signal read from the inverse quantization section 70, and is specifically described. As shown in FIG. 9, the up-sampler 72a and the low-pass filter 7
2b, a delay circuit 72c, an upsampler 72d,
It has a high-pass filter 72e and an adder 72f. That is, the vertical wavelet inverse transform unit 72 has the same configuration as the vertical wavelet inverse transform unit 18 '.

Here, the upsampler 72a doubles the signal rate of the video signal read from the first inverse quantization section 70a, and is similar to the upsampler 18a of the first embodiment. Configuration. That is, specifically, 0 data for one line is input every other line in the horizontal direction. The low-pass filter 72b is a low-pass filter used for wavelet inverse transform.
This low-pass filter 18b is also specifically configured as shown in FIG. The delay circuit 72c delays the video signal by one line in the horizontal direction.
Here, the delay circuit 72c is provided because it is necessary to delay the addition in the adding section 72f as the adding means. The upsampler 72d doubles the signal rate of the video signal read from the second inverse quantization unit 70b. Also,
The high-pass filter 72e is a high-pass filter used for inverse wavelet transform.
It is configured as shown in FIG. The upsampler 72a functions as a low-frequency side upsampler, and the upsampler 72d functions as a high-frequency side upsampler. Further, the low-pass filter 72b, the high-pass filter 72e, and the adder 72f function as a combining unit.

The output processing section 74 converts the output from the vertical wavelet inverse transform section 72 into a predetermined format of the second video signal and outputs the second video signal. That is, the digital video signal is D / A converted and output to the outside as a second video signal.

The operation of the scanning line converter B having the above configuration will be described. First, the first video signal is input to the input processing unit 60. Then, the input processing unit 60 performs A / D conversion on the input first video signal as a digital signal, and converts it into a luminance Y signal and two color difference signals. The input processing unit 60 sends the converted video signal to the conversion processing unit 12. Next, the conversion processing unit 62 performs a thinning process so that the video signal has the number of scanning lines of the second video signal. The video signal on which the thinning process has been performed is sent to the vertical wavelet conversion unit 64.

Next, in the vertical wavelet conversion section 64, the video signal from the conversion processing section 62 is subjected to filter processing by the low-pass filter 64a. afterwards,
The signal rate is halved by the downsampler 64b and output to the first quantization unit 66a. On the other hand, the video signal from the conversion processing unit 62 is delayed by the delay circuit 64c, and then subjected to a filtering process by the high-pass filter 64c. After that, the signal rate is reduced to half by the down sampler 64e and output to the second quantization unit 66b.

Next, in the quantization section 66, quantization is performed. That is, in the first quantization unit 66a, the video signal from the down sampler 64b is quantized by the first quantization table. That is, fine quantization is performed. On the other hand, in the second quantization section 66b, the video signal from the down sampler 64e is quantized by the second quantization table. That is, rough quantization is performed.

Next, the video signal output from the quantization section 66 is stored in the image memory 68. Here, since the delay is performed by the delay circuit 64c in the vertical wavelet transformer 64, the video signal from the first quantizer 66a and the video signal from the second quantizer 66b are alternately written to the image memory 68. Will be performed. Writing to the image memory 68 is performed in synchronization with the clock of the first video signal.

Next, the video signal stored in the image memory 68 is read by the inverse quantization unit 70. here,
The first inverse quantization unit 70a reads the video signal output from the first quantization unit 66a, that is, the video signal that has been subjected to the low-pass filter processing, while the second inverse quantization unit 70b
Reads the video signal output from the second quantization unit 66b, that is, the video signal that has been subjected to the high-pass filtering. Note that reading from the image memory 68 is performed with a clock synchronized with the second video signal.

The first inverse quantization section 70a performs inverse quantization according to the first quantization table.
The second inverse quantization unit 70b performs inverse quantization according to the second quantization table. The video signal inversely quantized by the first inverse quantization unit 70a is sent to the upsampler 72a of the vertical wavelet inverse transformation unit 72, while the video signal inversely quantized by the second inverse quantization unit 70b. Is an upsampler 72 of the vertical wavelet inverse transform unit 72
b.

Next, the vertical wavelet inverse transform unit 7
In 2, the signal rate is doubled by the upsamplers 72a and 72d. That is, the first inverse quantization unit 70
The video signal from a is processed by the upsampler 72a, while the video signal from the first inverse quantization unit 70b is processed by the upsampler 72b. That is,
In both the upsamplers 72a and 72d, reading is performed from the inverse quantization unit 70 in a certain horizontal period, and reading is stopped in the next horizontal period. Then, in the next horizontal period, reading from the inverse quantization unit 70 is performed again. That is, the video signals output from the upsamplers 72a and 72d have line data composed of 0 data inserted every other line.

Next, the video signal output from the upsampler 72a is filtered by a low-pass filter 72b, and the video signal output from the upsampler 72d is filtered by a high-pass filter 72e. Is done. The video signal from the low-pass filter 72b is delayed by the delay circuit 72c,
f. On the other hand, the video signal from the high-pass filter 72e is sent to the adder 72f as it is. Therefore, the low-frequency component and the high-frequency component are input to the adding unit 72f at the same timing, and the two frequency components are combined. Then, the video signal is output from the adding unit 72f to the output processing unit 74. In the output processing unit 74, the video signal is D / A converted and output to the outside as a second video signal.

As described above, according to the scanning line conversion apparatus B of this embodiment, the band division is performed by the wavelet conversion, the down-sampler is performed, and the low-frequency components are finely quantized. Since the band frequency components are roughly quantized, the capacity of the image memory can be reduced while preventing the image quality from deteriorating.

Although the above description has been made on the assumption that the frequency band is divided into the high frequency component and the low frequency component, the present invention is not limited to this.
Band division is possible to the power. In this case, the lower the frequency component, the finer the quantization. In the above description, the quantization unit 66 includes the first quantization unit 66a and the second quantization unit 66b.
0, the first inverse quantization unit 70a and the second inverse quantization unit 70b
However, the first quantization unit 66a and the first inverse quantization unit 70a may be omitted. In addition, when scanning line conversion is performed in both the vertical direction and the horizontal direction, FIG.
In addition to the configuration, a conversion processing unit that performs thinning processing of the number of pixels in the horizontal direction, a horizontal wavelet conversion unit that performs wavelet conversion in the horizontal direction, and a horizontal wavelet inverse conversion unit that performs inverse wavelet conversion in the horizontal direction Will be provided.

[0054]

According to the video processing apparatus according to the present invention,
The required capacity of the image memory can be reduced without deteriorating the image quality after scanning line conversion.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a scanning line conversion device according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a scanning line conversion device according to a first embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating a configuration of a conversion processing unit.

FIG. 4 is an explanatory diagram illustrating a configuration of a downsampler.

FIG. 5 is an explanatory diagram showing a configuration of an upsampler.

FIG. 6 is an explanatory diagram illustrating a configuration of a low-pass filter.

FIG. 7 is a block diagram showing a configuration of a vertical wavelet transform unit and a vertical wavelet inverse transform unit.

FIG. 8 is a block diagram illustrating a configuration of a scanning line conversion device according to a second embodiment of the present invention.

FIG. 9 is a block diagram illustrating a configuration of a scanning line conversion device according to a second embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a conventional scanning line conversion device.

[Explanation of symbols]

 A, B Scanning line converter 10, 60, 110 Input processor 12, 62, 112 Conversion processor 14, 64 Vertical wavelet converter 14a, 64a, 72b Low-pass filter 14b, 64b, 64e Downsampler 18a, 72a , 72d Upsampler 16, 68, 114 Image memory 18, 72 Vertical wavelet inverse transformation unit 20, 74, 116 Output processing unit 64d, 72e High-pass filter 66 Quantization unit 70 Inverse quantization unit 72f Addition unit

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 7/01 H04N 7/01 G

Claims (15)

[Claims] 1. A video processing device for converting a scanning line of a video signal, comprising: a conversion processing unit for performing a thinning process on a scanning line for a video signal to be converted; Band dividing means for dividing the band into bands, processing means for performing processing according to frequency bands on the video signal divided by the band dividing means, and storing the video signal processed by the processing means A video processing device comprising: 2. The video processing apparatus according to claim 1, wherein the band division by said band dividing means is performed by a wavelet transform. 3. The video processing apparatus according to claim 1, wherein the processing unit discards a video signal of a high frequency component. 4. The processing means performs processing for reducing a signal rate of a video signal which is not discarded, and the video processing device further restores a signal rate of a video signal read from the storage means. The video processing device according to claim 3, further comprising a signal rate restoring unit. 5. The video processing device according to claim 4, wherein the video processing device further includes a filter processing unit that performs a filtering process on the video signal whose signal rate has been restored. 6. The processing means performs quantization on the video signal in accordance with a quantization table having a quantization step smaller as the frequency component becomes lower, and the video processing device further reads from the storage means. The video processing apparatus according to claim 1, further comprising an inverse quantization unit that performs inverse quantization on the obtained video signal of each frequency band in accordance with the same quantization table as used for quantization. 7. The image processing device according to claim 7, wherein the processing unit performs processing for reducing a signal rate of the video signal.
7. The video processing device according to claim 6, further comprising a synthesizing unit for restoring the signal rate of the video signal from the inverse quantization unit and synthesizing video signals of a plurality of frequency bands. 8. The video processing apparatus according to claim 7, wherein said synthesizing means includes a filter processing means for performing a filtering process on the video signal whose signal rate has been restored. 9. The video processing apparatus according to claim 7, wherein the combining by the combining means is performed by inverse wavelet transform. 10. A video processing device for converting a scanning line of a video signal, comprising: a conversion processing unit for performing a thinning process on a scanning line for a video signal to be converted; Band extracting means for extracting video signals of a plurality of frequency bands; and for the video signal extracted by the band extracting means,
Signal rate reducing means for reducing the signal rate; storage means for storing the video signal having the reduced signal rate; signal rate restoring means for reading the video signal stored in the storage means and restoring the signal rate; A video processing apparatus for performing a filtering process on a video signal whose signal rate has been restored. 11. The video processing apparatus according to claim 10, wherein the extraction by the band extracting means is performed by a wavelet transform, and the filter processing means is performed by an inverse wavelet transform. 12. A video processing apparatus for converting a scanning line of a video signal, comprising: a conversion processing unit for performing a thinning process on a scanning line for a video signal to be converted; and a wavelet conversion unit, wherein the thinning process is performed. A wavelet transform unit having a low-pass filter for performing low-pass filtering on the processed video signal, and a downsampler for reducing a signal rate of the video signal on which low-pass filtering has been performed; Storage means for storing the video signal from the wavelet conversion means; an upsampler for recovering the signal rate of the video signal stored in the storage means, which is a wavelet inverse conversion means; and a video signal having the recovered signal rate. Wavelet inverse transform means having a low-pass filter for performing low-pass filtering on the image signal Location. 13. A video processing apparatus for converting a scanning line of a video signal, comprising: a conversion processing unit for performing a thinning process on a scanning line for a video signal to be converted; and a wavelet conversion unit, wherein the thinning process is performed. A low-pass filter that performs low-pass filtering on the processed video signal, a low-frequency side downsampler that reduces the signal rate of the video signal that has been subjected to low-pass filtering, and a thinning process is performed. A high-pass filter that performs high-pass filtering on the video signal, and a high-frequency-side downsampler that reduces the signal rate of the video signal on which high-pass filtering has been performed; A first quantization unit for quantizing a video signal from the wavelet transform unit, the first quantization unit performing quantization on the video signal from the low-frequency side downsampler; A second quantization unit that performs quantization on the video signal from the high-frequency side downsampler, wherein the quantization step of the first quantization unit is finer than the quantization step of the second quantization unit. A set quantization means; a storage means for storing the video signal from the wavelet transform means; and a wavelet inverse transform means, wherein a low signal for restoring the signal rate of the video signal stored in the storage means is provided. A band-side upsampler, a low-pass filter that performs low-pass filtering on the video signal whose signal rate has been restored by the low-band upsampler, and a signal rate of the video signal stored in the storage unit. A high-pass upsampler for performing the high-pass filtering on a video signal whose signal rate has been restored by the high-pass upsampler; Image processing apparatus characterized by having a wavelet inverse transform means having adding means for adding the video signal from the video signal and the high pass filter from. 14. The method according to claim 1, wherein the division or extraction of the frequency band is performed in the vertical direction of the screen.
Or the video processing device according to 12 or 13. 15. The method according to claim 4, wherein, when the signal rate is restored, line data composed of 0 data is inserted into the video signal.
14. The video processing device according to 1 or 12 or 13.