Image display apparatus, image signal processing apparatus, and image signal processing method

According to one embodiment, there is provided an image signal processing apparatus includes an interlace-to-progressive conversion circuit and a resolution enhancement circuit. The interlace-to-progressive conversion circuit outputs first signals by performing an interlace-to-progressive conversion process on image signals. The resolution enhancement circuit outputs second signals by performing a resolution enhancement process on the first signals. The resolution enhancement circuit performs the resolution enhancement process not on the first signals on which an interpolation process for dynamic images have been performed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2006-348122, filed Dec. 25, 2006, the entire contents of which are incorporated herein by reference.

BACKGROUND

An aspect of the present invention relates to an image display apparatus, an image signal processing apparatus, and an image signal processing method.

2. Description of the Related Art

JP-A-2005-20761 discloses an image signal processing apparatus that carries out a resolution enhancement process of inputted image signals (super resolution image processing).

However, there is a fear that high quality and highly resolved images processing can not be obtained when carrying out resolution enhancement processing for image signals inputted from an interlace-to-progressive conversion circuit. In the image signals in which an interpolation process for dynamic images has been carried out by the interlace-to-progressive conversion circuit, interpolated signals deteriorate in comparison with the original image signals. Therefore, where the image signals in which an interpolation process for dynamic images has been carried out are used as the original image signals for a resolution enhancement process, it is not possible to obtain sharp image signals due to influence of deteriorated signals.

DETAILED DESCRIPTION

Various embodiments according to the invention will be described hereinafter with reference to the accompanying drawings. In general, according to one embodiment of the invention, there is provided According to an aspect of the present invention there is provided an image signal processing apparatus including an interlace-to-progressive conversion circuit and a resolution enhancement circuit. The interlace-to-progressive conversion circuit outputs first signals by performing an interlace-to-progressive conversion process on image signals. The resolution enhancement circuit outputs second signals by performing a resolution enhancement process on the first signals. The resolution enhancement circuit performs the resolution enhancement process not on the first signals on which an interpolation process for dynamic images have been performed.

Hereinafter, a description is given of a preferred embodiment of the present invention with reference to the accompanying drawings. To facilitate understanding of the description, components that are identical to each other in the respective drawings are given the same reference numerals whenever possible, wherein overlapping description thereof is omitted.

Referring toFIG. 1, a description is given of a structure of an image signal processing apparatus1according to the present embodiment.FIG. 1is an exemplary block diagram showing the structure of the image signal processing apparatus1according to the present embodiment. The image signal processing apparatus1is provided with an interlace-to-progressive conversion circuit3and a resolution enhancement circuit5.

The interlace-to-progressive conversion circuit3carries out an interlace-to-progressive conversion process. That is, the circuit3determines dynamic images and still images by detecting movements of images in inputted images (Brightness signal (Y signal) and color difference signal (C signal)), wherein, when still images are determined, an interpolation process for still images is carried out, and when dynamic images are determined, an interpolation process for dynamic images is carried out. The interlace-to-progressive conversion circuit3outputs image signals (Y signals and C signal), in which an interlace-to-progressive conversion process has been carried out, to the resolution enhancement circuit5. Herein, the image signals (Y signals and C signals) outputted from the interlace-to-progressive conversion circuit3are image signals (Y signals and C signals) of low resolution.

Where the image signals outputted from the interlace-to-progressive conversion circuit3are determined to be still images, the image signals include original image signals inputted into the interlace-to-progressive conversion circuit3and image signals in which an interpolation process for still images has been carried out. Image signals of different fields in the original image signals inputted in the interlace-to-progressive conversion circuit3are employed for the image signals in which an interpolation process for still images has been carried out.

On the other hand, where determined to be dynamic images, the image signals outputted from the interlace-to-progressive conversion circuit3include original image signals inputted into the interlace-to-progressive conversion circuit3and image signals in which an interpolation process for dynamic images has been carried out. The image signals in which an interpolation process for dynamic signals are obtained by calculations from image signals between fields in the original image signals are inputted into the interlace-to-progressive conversion circuit3. Thus, since the image signals in which an interpolation process for dynamic images has been carried out are obtained by calculations, the image signals deteriorate in comparison with the image signals in which an interpolation process for still images has been carried out, wherein the reliability of signals is low.

The interlace-to-progressive conversion circuit3outputs the above-described results of determination for dynamic images and still images as movement detection signals. The movement detection signals outputted from the interlace-to-progressive conversion circuit3are inputted into the resolution enhancement circuit5.

The resolution enhancement circuit5performs the resolution enhancement process on the image signals (Y signals and C signals) inputted from the interlace-to-progressive conversion circuit3, and outputs the image signals (Y signals and C signals) that were subjected to the resolution enhancement process. Herein, the image signals (Y signals and C signals) outputted from the resolution enhancement circuit5are image signals (Y signals and C signals) of high resolution.

The resolution enhancement circuit5includes a first resolution enhancement circuit10for processing Y signals of low resolution to high resolution, and a second resolution enhancement circuit20for processing C signals of low resolution to high resolution.

FIG. 2is an exemplary block diagram describing a configuration of the first resolution enhancement circuit10. The first resolution enhancement circuit10is provided, as shown inFIG. 2, with an expansion filter portion11, a sub-pixel shift retrieval portion12, corresponding point calculation portions13and16, error calculation portions14and17, and provisional resolution image correction portions15and18.

The expansion filter portion11expands image signals, which are inputted from the interlace-to-progressive conversion circuit3, by a scaling filter process. Accordingly, image signals (Y signals) of low resolution will be converted to image signals (Y signals) that are provisionally highly resolved. The expansion filter portion11outputs the provisionally highly resolved image signals (image signals of provisional high resolution) to the corresponding point calculation portion13and the provisional resolution image correction portion15.

The sub-pixel shift retrieval portion12first detects autocorrelation of images in those of low resolution based on the image signals (Y signals) inputted from the interlace-to-progressive conversion circuit3. And, the sub-pixel shift retrieval portion12obtains a sub-pixel shift from the detection result of autocorrelation of the images in those of low resolution, and outputs a self-coalesce corresponding point. The sub-pixel shift retrieval portion12outputs the self-coalesce corresponding point to the corresponding point calculation portion13and the error calculation portion14.

Herein, the sub-pixel shift retrieval portion12selects original image signals for sub-pixel shift based on the movement detection signals outputted from the interlace-to-progressive conversion circuit3. That is, the sub-pixel shift retrieval portion12determines, based on the movement detection signal inputted from the interlace-to-progressive conversion circuit3, whether the image signals inputted from the interlace-to-progressive conversion circuit3include image signals in which an interpolation process for dynamic images has been carried out.

And, the sub-pixel shift retrieval portion12does not use the image signals, in which an interpolation process for dynamic images has been carried out, as original image signals for sub-pixel shift when the image signals inputted from the interlace-to-progressive conversion circuit3include the image signals in which an interpolation process for dynamic images has been carried out. At this time, the sub-pixel shift retrieval portion12uses the image signals inputted from the interlace-to-progressive conversion circuit3, that is, the image signals (original image signals for an interlace-to-progressive conversion process) inputted into the interlace-to-progressive conversion circuit3and the image signals, in which an interpolation process for still images has been carried out, as the original image signals for sub-pixel shift.

On the other hand, when the image signals inputted from the interlace-to-progressive conversion circuit3includes image signals in which an interpolation process for still images has been carried out, the sub-pixel shift retrieval portion12uses image signals inputted from the interlace-to-progressive conversion circuit3, that is, image signals inputted into the interlace-to-progressive conversion circuit3and image signals, in which an interpolation process for still images has been carried out, as original image signals for a resolution enhancement process.

Outputs from the expansion filter portion11and the sub-pixel shift retrieval portion12are inputted into the corresponding point calculation portion13. The corresponding point calculation portion13calculates, by a weighting addition computation, the point corresponding to the self-coalesce corresponding point from provisional high resolution images based on the image signals (Provisional high resolution image signals) inputted from the expansion filter portion11. The corresponding point calculation portion13outputs the result of calculation (point corresponding to the self-coalesce corresponding point) to the error calculation portion14.

Outputs from the corresponding point calculation portion13and the sub-pixel shift retrieval portion12are inputted into the error calculation portion14. The error calculation portion14calculates an error between the point corresponding to the self-coalesce corresponding point, which is outputted from the corresponding point calculation portion13, and the self-coalesce corresponding point outputted from the sub-pixel shift retrieval portion12. The error calculation portion14outputs the result (the above-described error) of calculation to the provisional resolution image correction portion15.

Outputs from the expansion filter portion11and the error calculation portion14are inputted into the provisional resolution image correction portion15. The provisional resolution image correction portion15corrects the images signals (Provisional high resolution image signals) inputted from the expansion filter portion11based on the above-described error calculated by the error calculation portion14. The provisional resolution image correction portion15outputs the corrected image signals (Provisional high resolution image signals) to the corresponding point calculation portion13and the provisional resolution image correction portion15.

As in the above-described corresponding point calculation portion13, the corresponding point calculation portion16calculates, by a weighting addition computation, the point corresponding to the self-coalesce corresponding point from provisional high resolution images based on the image signals (Provisional high resolution image signals) inputted from the provisional resolution image correction portion15. The corresponding point calculation portion16outputs the result (the point corresponding to the self-coalesce corresponding point) to the error calculation portion17.

As in the above-described error calculation portion14, the error calculation portion17calculates an error between the point corresponding to the self-coalesce corresponding point outputted from the corresponding point calculation portion16and the self-coalesce corresponding point outputted from the sub-pixel shift retrieval portion12. The error calculation portion17outputs the result (the above-described error) of calculation to the provisional resolution image correction portion18.

As in the above-described provisional resolution image correction portion15, the provisional resolution image correction portion18corrects the image signals (Provisional high resolution image signals) inputted from the provisional resolution image correction portion15based on the above-described error calculated by the error calculation portion17.

As described above, the first resolution enhancement circuit10repeats a series of processes of the corresponding point calculation, error calculation and correction of provisional high resolution images several times (two times in the present embodiment), and obtains image signals (Y signals) of sharpened high resolution. The first resolution enhancement circuit10outputs the high resolution image signals (Y signals) thus obtained.

The second resolution enhancement circuit20converts the image signals (C signals) inputted from the interlace-to-progressive conversion circuit3in terms of linear HD (High Definition). The second resolution enhancement circuit20outputs the image signals (C signals), which were subjected to linear HD conversion, as high resolution image signals (C signals).

As described above, in the present embodiment, the sub-pixel shift retrieval portion12does not use the image signals, in which an interpolation process for dynamic images has been carried out, as original image signals for sub-pixel shift when the image signals inputted from the interlace-to-progressive conversion circuit3include image signals in which an interpolation process for dynamic images. That is, the resolution enhancement circuit5(the first resolution enhancement circuit10) does not use the image signals, in which an interpolation process for dynamic images has been carried out, for a resolution enhancement process. Therefore, it will be possible to obtain sharp image signals as high resolution image signals. As a result, with the image signal processing apparatus1, it is possible to obtain high-quality and high-resolution images.

Subsequently, referring toFIG. 3, a description is given of one example of a television set30(image display apparatus) provided with the above-described image signal processing apparatus1.FIG. 3is an exemplary block diagram showing one example of a television set provided with the above-described image signal processing apparatus1according to the present embodiment.

The television set30is provided with a tuner31, to which broadcasting signals are supplied from an antenna element, for outputting audiovisual signals by demodulating the same, and an AV switch (SW) portion33, to which the audiovisual signals are supplied, for carrying out switching with an external input, and a video signal conversion portion35that, when video signals are supplied thereto, carries out a predetermined video signal process, converts the same to Y signals and color difference signals, and outputs the same. The television set further includes an audio extraction portion43for separating audio signals from audiovisual signals, and an amplification portion45for appropriately amplifying the audio signals and supplying the same to the speaker47.

Herein, the above-described image signal processing apparatus1is applied to the image signal processing portion37to which video signals are supplied from the video signal conversion portion35. Non-interlaced video signals are divided into RGB signals by an RGB processor39, appropriately amplified by a CRT driver41and are displayed in a CRT42as a video.

Thus, the invention is not limited to the embodiments without modification. The invention can be implemented by modifying composite elements of embodiments without departing from the spirit and scope of the invention. Additionally, the invention can be variously implemented by appropriately combining a plurality of composite elements of the embodiments with one another, which are described in the foregoing description thereof. For example, some of the composite elements can be omitted among all the composite elements of the embodiments. Additionally, the composite elements, each of which is provided in different ones of the embodiments, can be appropriately combined with one another.