JP2005218009A - Image displaying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that motion blur is to be increased, and as a result, the motion blur in a hold type display is to be encouraged if an input video signal in accordance with a low frame rate is intended to raise its frame frequency and to remake a new video signal of a frame so that remade frame frequency meets to a time axis of a new frame frequency. <P>SOLUTION: A device comprises a frame generating method selecting function capable of selecting between reproduction of an original signal and output video signals in response to increased frame rates when the video signal is detected to be made in accordance with a low frame rate signal, wherein a scale factor for increasing the frame rate is made to be an integral multiple of original frame rate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a television or display using a device such as an LCD, and a projection video projector apparatus, and more particularly to an image display apparatus that converts and displays a frame rate of an input video signal.

  In recent years, in addition to CRTs, which have been the mainstream in the past as display devices, new display devices such as LCDs and PDPs have made remarkable progress, and image display apparatuses using these devices are also on the market. In particular, matrix-type image display devices represented by liquid crystal (LCD) display devices take advantage of the features of thinness, light weight, and low power consumption, as personal computer display devices, TV display devices, and projection-type display devices. Used in various fields.

  In particular, an image display device using liquid crystal has the advantages of thinness, light weight, and low power consumption. On the other hand, due to its characteristics, display quality may be impaired due to motion blur at the time of moving image display.

  In the TFT type liquid crystal image display device, the light output of the display image from the liquid crystal display element is maintained substantially constant for the luminance of the displayed image over one frame period of the image signal. An image display device having such display performance is sometimes referred to as a hold-type display. The hold-type display has a problem that image quality deterioration occurs due to motion blur when displaying a moving image (see, for example, Non-Patent Document 1).

  On the other hand, an image display apparatus using a display element with a short light emission period such as a CRT is sometimes called an impulse display. In the impulse display, image quality deterioration during moving image display such as a hold type does not occur in actual use. .

  As a means for solving the image quality degradation problem when displaying a moving image on the hold type display, a method of shortening the hold time of the display light of the liquid crystal display element to make it close to an impulse type light emission such as a CRT, As a method, the principle proposal of the method of raising the frame frequency of display (shortening one frame period) and minimizing the integration causing the motion blur as described above and the effect thereof have been reported (for example, Non-Patent Document 1). reference.).

  However, the former method in which the hold time is shortened has a problem that the display luminance is reduced in proportion to the shortening of the hold time. Therefore, the latter method of increasing the frame frequency is considered effective.

  Normally, for example, a 60 Hz interlaced signal is converted into a 60 Hz progressive signal and displayed, but the display frame frequency is increased by 1.5 or 2 times.

When raising the frame frequency, it is necessary to recreate the frame video signal along the time axis of the new frame frequency, but they are generally produced based on the frame of the input video signal or the field video signal.
IEICE Technical Report EID99-10, pp55-60, 1999

  However, when the input video signal is made based on a movie material, generally, 24 frames per second are converted into a 60 Hz interlace signal, that is, the video signal is 24 Hz on average. Contains only video information. When an input video signal based on such a low frame rate is increased in frame frequency in the same manner as an input signal of 60 Hz, and the video signal of the frame is recreated along the time axis of the new frame frequency, the video is processed. In other words, the motion blur increases, and as a result, the motion blur of the hold type display may be promoted.

  In addition, since information of a rate of, for example, 24 Hz of the original image is forcibly applied to the new frame frequency, the time distribution of the frames of the original image is not uniform, and the motion expression may be unnatural.

  The present invention has been made in consideration of the above circumstances. When an input signal is converted to a high frame rate and displayed, the original image does not promote motion blur for an input video signal having a low frame rate. Rather, it is an object of the present invention to provide an image display device that can be improved and display a smooth movement.

  In order to solve these problems, the first invention of the present application is to increase the frame frequency of an input video signal and output it as a different frame frequency, and to increase the frame rate of the input video signal by the frame rate conversion circuit. Frame video generation circuit that creates frame video signals corresponding to different frame frequencies, and detects whether the input video signal was created based on a low frame rate signal such as movie material and outputs the result An original frame rate detecting circuit, and when the original frame rate detecting circuit detects that the input video signal is created based on a low frame rate signal, the frame video generating circuit The original original signal is reproduced and output in accordance with the frame rate increased by the frame rate conversion circuit. An image display device includes a frame generating method selecting function capable of selecting and.

  The second invention of the present application is a configuration in which the frame rate conversion circuit can switch the conversion magnification for frame rate conversion depending on whether or not the input video signal is created based on a low frame rate signal, When the original frame rate detection circuit detects that the input video signal is created based on a low frame rate signal, the frame rate conversion circuit changes the magnification for increasing the frame rate of the input signal, and the magnification is The image display device is an integer multiple of the original frame rate detected by the original frame rate detection circuit.

  According to the present invention, even when the original image of the input signal has a low frame rate based on, for example, a movie material of 24 frames per second, the motion blur is improved by increasing the frame frequency without increasing the motion blur. It is possible to display, and the time distribution of the frames of the original image becomes uniform, so that a remarkable effect can be obtained that a smooth moving image can be displayed.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

(Embodiment 1)
FIG. 1 is a block diagram of the main configuration of the image display apparatus according to the first aspect of the present invention. In FIG. 1, 1 is a liquid crystal display element, and 2 is a display for driving the liquid crystal display element based on a video signal. Element drive circuit 3 is a frame rate conversion circuit that converts the frame frequency of the video signal, and 4 is a frame video generation that creates a frame video signal that is increased by the frame rate conversion circuit 3 and corresponds to a different frame frequency from the input video signal A circuit 5 is an original frame rate detection circuit that detects whether an input video signal is created based on a low frame rate signal such as a movie material and outputs the result.

  In FIG. 1, for convenience of explanation, the frame rate conversion circuit and the frame signal generation circuit are expressed as separate blocks, but both may be processed simultaneously in the same block, which is the content of the present invention. There is no limit.

  In the following description, interlace is represented by i, progressive is represented by p, field frequency of the interlace signal or frame frequency of the progressive signal is represented by a number. For example, an interlace signal having a field frequency of 60 Hz may be described as 60i.

  The operation will be described below with reference to FIG.

  Although there is a case where the pre-processing of the video signal is present in the former stage of FIG. 1, this time, the configuration and illustration are omitted.

  First, an example in which a 60i video signal is displayed at 90p will be described.

  In FIG. 1, the video signal input to the image display device of the present invention is input to the frame rate conversion circuit 3. The 60i video signal input to the frame rate conversion circuit 3 is converted to a frame frequency of 90p there. On the other hand, the video signal input to the image display device is also input to the original frame rate detection circuit 5, where it is detected whether the frame rate of the original image of the input signal is 24p, for example. In this example, information that is not 24p is output as the original frame rate information and is input to the frame video generation circuit 4.

  The original frame rate information from the original frame rate detection circuit 5 is also input to the frame rate conversion circuit 3, and the case where the operation of the frame rate conversion circuit 3 becomes special due to this will be described later.

  Next, the frame video generation circuit 4 generates a frame signal (intermediate frame) corresponding to 90p from the video signal. The frame video generation circuit 4 will be further described with reference to FIG. The frame image generation circuit 4 includes a frame generation method selection unit 41, an intermediate frame generation unit 42, an original frame reproduction / count unit 43, and a frame memory 44. The frame generation method selection unit 41 receives input original frame rate information. Accordingly, the processing of the video signal can be switched between using the intermediate frame generation unit 42 and using the original frame reproduction / counting unit 43.

  The intermediate frame generation unit 42 has a function of creating a new frame image corresponding to the frame frequency based on the field or frame image information.

  The original frame reproduction / counting unit 43 has a function of reproducing the original image of the original frame in accordance with the regularity of the field image arrangement, and successively outputting several reproduced original images according to the frame frequency. Yes.

  The memory used for signal processing in the frame video generation circuit 4 is shared with the frame memory 44.

  In this example, the frame generation method selection unit 41 uses the intermediate frame generation unit side according to the input original frame rate information. The operation in that case will be described with reference to FIG.

  FIG. 3 conceptually shows an example of frame conversion from 60i to 90p. Fields A, B, C, D,. . . Is a 90 Hz progressive signal aa, ab, bc,. . . Has been converted.

  Next, an example will be described in which a video signal of 60i but using a movie material 24p as an original image is displayed as 90p.

  In FIG. 1, the video signal input to the image display device of the present invention is input to the frame rate conversion circuit 3. The 60i video signal input to the frame rate conversion circuit 3 is converted to a frame frequency of 90p there. On the other hand, the video signal input to the image display device is also input to the original frame rate detection circuit 5, where it is detected whether or not the frame rate of the original image of the input signal is 24p, which is 24p in this example. Is output as original frame rate information and input to the frame video generation circuit 4.

  Next, the frame video generation circuit 4 generates a frame signal corresponding to 90p from the video signal. The operation of the frame video generation circuit 4 will be further described with reference to FIG. The frame generation method selection unit 41 in the frame video generation circuit 4 uses the original frame rate information that the original frame rate of the video signal is 24p, so that the processing of the video signal is performed using the original frame reproduction / counting unit 43. Switch. FIG. 4 shows a conceptual diagram of processing in the original frame reproduction / counting unit 43.

  In FIG. 4, first, due to the regularity of the field image arrangement, a 24p original image is reproduced from a 60i input signal, and several reproduced original images are continuously output in accordance with a 90p frame frequency. The In the example of FIG. 4, the original signals A, B, C, D,. . . Are 90 Hz progressive signals 4, 4, 4, 3,. . . Is output.

  If such an input signal is a signal based on a low frame rate such as 24p of a movie material, and if the general processing as shown in FIG. 3 is performed, the order of field images is regular. However, since the same processing as when the time interval between fields is constant is performed, the converted 90p signal becomes a blurred signal in which field information is mixed.

  However, in the image display device of the present invention, when the input signal is a signal based on a low frame rate such as 24p of a movie material, the frame of the original image is output continuously, so that the switching of the video is clear and blurring. The frame frequency can be increased without increasing it.

  When the display element is a liquid crystal, increasing the frame frequency to be displayed has the following effects against motion blur.

  In the liquid crystal, since the electric capacitance of the pixel varies depending on the voltage, the voltage may be applied a plurality of times, that is, a plurality of frames in order to achieve a desired transmittance. Here, by increasing the frame frequency, the number of times that a voltage can be applied in a certain time increases, so that the achievement time to a desired transmittance is shortened, and as a result, the response time of the liquid crystal display element is shortened. In other words, since it becomes possible to respond at high speed, there is an effect of improving motion blur.

  Since this effect is added, even if the intermediate frame as shown in FIG. 3 cannot be successfully produced, a 60i signal based on a low frame rate such as 24p is displayed on the liquid crystal display element as 60p or 48p, for example. Compared with the case where it ends up, the improvement effect with respect to motion blur is remarkable.

  On the other hand, in the example of FIG. 4, since the information of the rate of 24 Hz of the original image is forcibly applied to the new frame frequency of 90 Hz, the time distribution of the frames of the original image is not uniform. In this case, the motion expression may become unnatural.

  However, as shown in FIG. 1 as the second invention of the present application, the original frame rate information from the original frame rate detection circuit 5 is also input to the frame rate conversion circuit 3.

  Therefore, the frame rate conversion circuit 3 can change the magnification of the frame rate conversion based on the original frame rate information. For example, when the original frame rate is 24 Hz, the frequency is increased to an integral multiple of, for example, three times 72 Hz or four times 96 Hz. Can be converted.

  The frame image generation circuit 4 operates in accordance with a new frame frequency that is an integral multiple of the original frame rate. The operation will be described with reference to FIG.

  FIG. 5 is a conceptual diagram of processing in the original frame reproduction / counting unit 43 when the frame rate is converted to 72 Hz, which is three times that when the original frame rate is 24 Hz.

  In FIG. 5, first, due to the regularity of the field image arrangement, a 24p original image is reproduced from an input signal of 60i, and several reproduced original images are continuously output in accordance with a frame frequency of 72p. The Here, since the frame frequency is three times the original frame rate, the original signals A, B, C, D,. . . Is a progressive signal of 3, 3, 3, 3,. . . Is output. In this way, the time distribution of the original frames becomes even, and the motion expression becomes smooth and natural.

  The image display device of the present invention improves motion blur by increasing the frame frequency without increasing motion blur even when the original image of the input signal has a low frame rate based on, for example, a movie material of 24 frames per second. TV, display, and projection video projector using a liquid crystal device, which have the remarkable effect that the time distribution of the frames of the original image can be made uniform and a smooth video can be displayed. It is useful as an apparatus, particularly an image display apparatus that converts and displays the frame rate of an input video signal.

1 is a block diagram of a main configuration of an image display device according to a first embodiment of the present invention. FIG. 1 is a block diagram of the main configuration of the frame video generation circuit in FIG. Conceptual diagram of frame conversion example Conceptual diagram of processing in original frame playback / counting unit 43 Conceptual diagram of processing in original frame reproduction / counting unit 43 in the second invention of the present application

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display element 2 Display element drive circuit 3 Frame rate conversion circuit 4 Frame image generation circuit 5 Original frame rate detection circuit 41 Frame generation method selection part 42 Intermediate frame generation part 43 Original frame reproduction | regeneration / count part 44 Frame memory

Claims (5)

A frame rate conversion circuit that increases the frame frequency of the input video signal and outputs it as a different frame frequency, and a frame video that is increased by the frame rate conversion circuit and that corresponds to a different frame frequency from the input video signal. A generation circuit; and an original frame rate detection circuit that detects whether the input video signal is generated from a frame rate lower than a preset frame rate and outputs a result, and the frame video generation circuit includes: An image display apparatus comprising a frame generation method selection function capable of switching a method of generating the frame video signal according to an output of the original frame rate detection circuit. When the original frame rate detection circuit detects that the input video signal is generated based on a low frame rate signal, the frame video generation circuit reproduces the original signal from which the input video signal is based. The image display apparatus according to claim 1, wherein output can be selected in accordance with the frame rate increased by the frame rate conversion circuit. A frame rate conversion circuit that increases the frame frequency of the input video signal and outputs it as a different frame frequency, and a frame video that is increased by the frame rate conversion circuit and that corresponds to a different frame frequency from the input video signal. A generation circuit; and an original frame rate detection circuit that detects whether the input video signal is generated from a frame rate lower than a preset frame rate and outputs a result, and the frame rate conversion circuit includes: An image display device characterized in that the conversion magnification for frame rate conversion is switched according to the output of the original frame rate detection circuit. When the original frame rate detection circuit detects that the input video signal is created based on a low frame rate signal, the frame rate conversion circuit changes the magnification for increasing the frame rate of the input signal. The image display device according to claim 1, wherein the image display device is characterized. When the original frame rate detection circuit detects that the input video signal is created based on a low frame rate signal, the frame rate conversion circuit increases the frame rate of the input video signal by a factor that increases the frame rate of the input video signal. 5. The image display device according to claim 3, wherein the image display device is an integral multiple of the original frame rate detected by the frame rate detection circuit.

Images