JP2009071444A - Pixel shift display device, pixel shift display method, and pixel shift display program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pixel shift display device or the like capable of performing more smooth moving image display in pixel shift display. <P>SOLUTION: The pixel shift display device includes: a motion interpolation image processing circuit 5 for generating at least one interpolation frame image pertinent to the time between two continuous frame images on the basis of moving image data constituted of the plurality of frame images; a pixel shift control circuit 6 for generating a field image corresponding to a pixel shift position from the frame images or interpolated frame images according to the time sequence of the frame images or the interpolated frame images; a display element 9 for successively displaying the field images; and a pixel shift element 10 for performing spatial shift of a pixel corresponding to the pixel shift position of the field image in synchronism with the display of the field image by the display element 9. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pixel-shifted display device, a pixel-shifted display method, and a pixel-shifted display program for generating a field image from a frame image and displaying it by performing spatial pixel shift.

  Techniques for improving the resolution of a display device have been proposed in the past. This technique is roughly divided into a spatial resolution improvement technique and a resolution improvement technique using temporal image movement. .

  As a technique for improving the former spatial resolution, for example, a technique described in a gazette according to Japanese Patent No. 2709070 can be cited. This technique is a technique for performing a display with a resolution higher than the resolution of the display element by controlling an image to be displayed and a spatial light beam shift.

  Japanese Patent Application Laid-Open No. 2001-296135 describes a technology of a pixel shift element using a TN liquid crystal and a birefringent plate, and the display element is provided by combining the display element and the pixel shift element. It is a technology that displays images at a resolution higher than the resolution.

  Further, Japanese Patent Application Laid-Open No. 11-296135 discloses an example of a material used as a birefringent plate and a delay amount in order to match a switching period between a polarization switching liquid crystal and a display element in which a response delay occurs with respect to a control signal. The technology that determines the drive waveform in anticipation of this is described.

  Japanese Patent Application Laid-Open No. 2005-57742 discloses a method for solving the difference between the number of display pixels and the number of pixels constituting the display element when performing pixel shifting (that is, the difference in resolution between image data and the display element). Describes a method of generating an image by interpolation. Although this publication describes a technique for spatial interpolation, it does not describe performing interpolation in the temporal direction.

On the other hand, the latter technique for improving the temporal resolution is realized by displaying a moving image. In recent years, in order to improve the smoothness of motion, for example, Japanese Patent Laid-Open No. 4-167688 and Japanese Patent Laid-Open No. 4-302289 describe a technique for generating and displaying an interpolated image between frames of moving images. Has been.
Patent Publication of Japanese Patent No. 2709070 JP 2001-296135 A JP-A-11-296135 JP-A-2005-57742 JP-A-4-167688 JP-A-4-302289

  The conventional technique for improving the spatial resolution by pixel shifting is to generate a field image at a plurality of pixel shifting positions from one frame image and display them sequentially according to the pixel position. When a moving object is displayed by technology, there is a problem that the movement may not be smooth.

  This problem will be described with reference to FIG. FIG. 15 is a diagram for explaining that a moving subject may not move smoothly when a moving image is displayed at a high resolution by a conventional technique using a technique of shifting two pixels in the horizontal direction. .

  First, it is assumed that the display element has a configuration of 4 × 6 pixels, for example, as schematically shown in FIG. 4 according to the embodiment of the present invention. As shown in FIGS. 15A, 15D, and 15G, the input moving image data is assumed to be a frame unit image with a period of 60 Hz having a 4 × 12 pixel configuration, for example. This moving image data is shifted in the horizontal direction by two-point pixels, and is displayed in 120 Hz field image units as shown in FIG. 15B, FIG. 15C, FIG. 15E, FIG. 15F, FIG. It is displayed as shown in 15 (I).

  15A is an image of the first frame, FIG. 15B is a field image of the position A generated from the image of the first frame, and FIG. 15C is generated from the image of the first frame. 15D is a second frame image, FIG. 15E is a position A field image generated from the second frame image, and FIG. 15F is the second frame image. FIG. 15G shows the image of the third frame, FIG. 15H shows the field image of the position A generated from the image of the third frame, and FIG. A field image at position B generated from the third frame image is shown.

  This technique generates field images at two positions (position A and position B) based on one frame image with a 60 Hz cycle, and sequentially displays them while shifting pixels at a cycle of 120 Hz. However, the time resolution is 60 Hz.

  FIG. 15 shows an example of a general 60 Hz period frame image in which the observer's recognition limit is taken into account. However, some of the input moving images have a 30 Hz period video format. In the case of a moving image, it is difficult to obtain smooth movement. Furthermore, even in the case of a moving image with a period of 60 Hz as shown in FIG. 15, in the case of a moving image including a subject with a high moving speed, there may be cases where sufficient smoothness of movement cannot be obtained. . As described above, it is not always possible to obtain a moving image with smooth motion simply by updating the display at the frequency of the input video format.

  Specifically, as shown in FIG. 15A, FIG. 15D, and FIG. 15G, for example, black diagonal lines that move from the left to the right are included in the input moving image data. It shall be. At this time, when paying attention to the line of sight of the observer observing the display image, the line of sight of the observer moves so as to smoothly follow the black diagonal line. When an observer observes a normal image without pixel shifting, the black image included in the 60 Hz period frame image as shown in FIGS. 15A, 15D, and 15G is used. While paying attention to the diagonal line, the line of sight is smoothly followed.

  On the other hand, when the observer observes an image in which the pixel is shifted, FIG. 15B, FIG. 15C, FIG. 15E, FIG. 15F, and FIG. The image as shown in FIG. 15I is observed. For example, the image shown in FIG. 15B (first frame position A) and the image shown in FIG. 15C (first frame position). In B), the position of the black diagonal line is hardly changed, whereas the image shown in FIG. 15C (first frame position B) and the image shown in FIG. 15D (second frame position A). ), The position of the black diagonal line is greatly moved to the right, so that it is perceived as a discontinuous movement. That is, while the line of sight tries to move smoothly, the displayed subject (black diagonal line) cannot move smoothly at a constant speed, so there is a deviation between the line of sight position and the object position, It is a display that is not perceived as being a smooth moving image display.

  In FIG. 15, the two-point pixel shift has been described as an example. However, in the case of the display using the four-point pixel shift, it is considered that the shift between the line-of-sight movement and the subject movement is further increased (that is, one field). Since the first to fourth fields are generated from the first frame image (that is, the subject hardly moves on the image), the fifth field is generated from the second frame image. Since the subject moves discontinuously and greatly between the field 5 and the 5th field), the smoothness of the moving image display is perceived as being impaired.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a pixel-shifted display device, a pixel-shifted display method, and a pixel-shifted display program capable of performing smoother moving image display in pixel-shifted display. It is said.

  In order to achieve the above object, the pixel-shifted display device according to the first invention is an interpolated frame image corresponding to a time between two consecutive frame images based on moving image data composed of a plurality of frame images. An interpolated image generating unit that generates one or more of the above, a field image generating unit that generates a field image corresponding to a pixel shift position from the frame image or the interpolated frame image according to the time order of the frame image or the interpolated frame image, A display unit that sequentially displays the field image; and a pixel shift unit that performs a spatial pixel shift according to a pixel shift position of the field image in synchronization with the display of the field image by the display unit. It is a thing.

  The pixel-shifted display device according to the second invention is the pixel-shifted display device according to the first invention, wherein the field image generation unit pixels one or more field images from one frame image or interpolated frame image. It is generated according to the shift position.

  Furthermore, the pixel shift display device according to the third invention is the pixel shift display device according to the first invention, wherein each frame image of the input moving image data is an appearance after the pixel shift is performed by the pixel shift unit. A pre-processing unit that performs resolution conversion so as to be the same as the number of display pixels, and the interpolation image generation unit is the same as the frame image based on the frame image that has been subjected to resolution conversion by the pre-processing unit. An interpolation frame image having the number of pixels is generated, and the field image generation unit generates a field image having the same number of pixels as that of the display unit from the frame image or the interpolation frame image.

  A pixel-shifted display device according to a fourth aspect of the present invention is the pixel-shifted display device according to the first aspect of the present invention, wherein a moving image / still image determination for determining whether input image data is moving image data or still image data. The interpolation image generation unit is configured to stop generating the interpolation frame image when the moving image / still image determination unit determines that the image data is still image data. The unit generates a field image corresponding to the pixel shift position from the still image data.

  A pixel shift display device according to a fifth aspect of the present invention further includes a scene change determination unit that detects whether or not a scene change has occurred in the input moving image data in the pixel shift display device according to the first aspect of the present invention, The interpolated image generating unit, when the scene change determining unit determines that a scene change has occurred, stops generating an interpolated frame image between frames in which the scene change has occurred. The generation unit generates a field image corresponding to a pixel shift position from one frame image between frames in which the scene change has occurred.

  A pixel shift display device according to a sixth aspect of the present invention further includes a switching unit for manually switching whether or not to generate an interpolation frame image by the interpolation image generation unit in the pixel shift display device according to the first aspect of the present invention. It is a thing.

  According to a seventh aspect of the present invention, there is provided a pixel-shifted display method that generates one or more interpolated frame images corresponding to a time between two consecutive frame images based on moving image data composed of a plurality of frame images. A step of generating a field image corresponding to a pixel shift position from the frame image or the interpolated frame image according to a time sequence of the frame image or the interpolated frame image, and a display step of sequentially displaying the field image And a pixel shifting step of performing spatial pixel shifting according to the pixel shifting position of the field image in synchronization with displaying the field image in the display step.

  The pixel-shifted display method according to an eighth invention is the pixel-shifted display method according to the seventh invention, wherein the field image generation step sets one or more field images from one frame image or interpolated frame image to a pixel shift position. It is a step which generates according to it.

  The pixel-shifted display method according to the ninth invention is the pixel-shifted display method according to the seventh invention, in which each frame image of the input moving image data is displayed in an apparent manner after the pixel shift is performed by the pixel-shifting step. A pre-processing step of performing resolution conversion so as to be the same as the number of pixels, and the interpolated image generation step is based on the frame image subjected to resolution conversion by the pre-processing step, and has the same number of pixels as the frame image. The field image generation step is a step of generating a field image having the same number of pixels as the number of pixels of the image displayed by the display step from the frame image or the interpolation frame image. is there.

  The pixel-shifted display method according to a tenth aspect of the present invention is the pixel-shifted display method according to the seventh aspect of the present invention, in which a moving image / still image determination is performed to determine whether input image data is moving image data or still image data. The interpolation image generation step includes a step of stopping the generation of the interpolation frame image when it is determined by the moving image / still image determination step that the image data is still image data. The step is a step of generating a field image corresponding to the pixel shift position from the still image data.

  A pixel shift display method according to an eleventh aspect of the invention further includes a scene change determination step for detecting whether or not a scene change has occurred in the input moving image data in the pixel shift display method according to the seventh aspect of the invention, The interpolated image generating step includes a step of stopping the generation of the interpolated frame image between the frames in which the scene change has occurred when it is determined in the scene change determining step that a scene change has occurred.

  A pixel shifted display method according to a twelfth aspect of the present invention is the pixel shifted display method according to the seventh aspect of the present invention, wherein the interpolation image generation step switches whether to generate an interpolation frame image according to a manual operation. Includes steps.

  A pixel shift display program according to a thirteenth aspect of the invention generates one or more interpolated frame images corresponding to a time between two consecutive frame images based on moving image data composed of a plurality of frame images. An interpolation image generation step, a field image generation step for generating a field image corresponding to a pixel shift position from the frame image or the interpolation frame image according to the time order of the frame image or the interpolation frame image, and the field image are sequentially displayed. And a pixel shifting step for performing a spatial pixel shift in accordance with a pixel shift position of the field image in synchronization with displaying the field image in the display step. .

  According to the pixel shift display device, the pixel shift display method, and the pixel shift display program of the present invention, it is possible to perform a smoother moving image display in the pixel shift display.

  Embodiments of the present invention will be described below with reference to the drawings.

[Embodiment 1]
1 to 7 show Embodiment 1 of the present invention, and FIG. 1 is a block diagram showing a configuration of a pixel shift display device.

  This pixel shift display device includes a preprocessing circuit 1 as a preprocessing unit, a moving image / still image determination circuit 2 as a moving image / still image determination unit, a frame memory data selector 3, a frame memory 4, and an interpolation image generation unit. A motion interpolation image processing circuit 5, a pixel shift control circuit 6 as a field image generation unit, a field memory 7, a timing controller 8, a display element 9 as a display unit, and a pixel shift element 10 as a pixel shift unit are provided. ing.

  Various video signals such as a still image / moving image, a video signal from a personal computer, and a television video signal are input to the preprocessing circuit 1. The pre-processing circuit 1 performs frame rate conversion, IP (interlace-to-progressive) conversion, or displays the various types of video signals on the pixel-shifted display device. Resolution conversion is performed so as to match the resolution, or color space conversion is performed. Here, the resolution conversion is performed so that an image corresponding to the apparent resolution after the pixel shift is obtained when the pixel shift display is performed.

  The moving image / still image determination circuit 2 determines whether the image related to the video signal input to the preprocessing circuit 1 is a moving image or a still image, the movement of the preceding and following frames, the format of the input interface, etc. It is determined based on.

  When the moving image / still image determination circuit 2 determines that the video signal is a moving image, for example, a plurality of continuous frames of images are stored in the frame memory 4, The interpolated image processing circuit 5 generates an interpolated frame image (intermediate frame image) corresponding to the time between two consecutive frame images.

  Note that the motion interpolation image processing circuit 5 includes a scene change determination unit 5a for determining whether or not a scene change has occurred when the video signal is a moving image.

  The frame memory data selector 3 sends a plurality of continuous frame images and the interpolated frame images generated as described above in the order of time and sequentially stores them in the field memory.

  The timing controller 8 generates a timing signal and the like for matching the timings of the frame memory data selector 3, the frame memory 4, the motion interpolation image processing circuit 5, the pixel shift control circuit 6, and the field memory 7. These are output.

  The pixel shift control circuit 6 controls the timing controller 8 and the frame memory data selector 3 so that the image displayed on the display element 9 and the pixel shift position by the pixel shift element 10 correspond to each other.

  The pixel shift control circuit 6 reads the pixel corresponding to the pixel shift position and outputs the field image to the display element 9 when reading the frame image or the interpolated frame image stored in the field memory 7. It has become.

  Next, FIG. 2 is a flowchart showing a branch of processing based on each determination of the moving image / still image determination circuit 2 and the scene change determination unit 5a in the motion interpolation image processing circuit 5.

  When this process is started, first, the moving image / still image determination circuit 2 determines whether the video signal from the preprocessing circuit 1 is a moving image or a still image (step S1).

  If it is determined in step S1 that the image is a still image, the interpolation frame image is not generated (that is, the motion interpolation image processing circuit 5 functions to stop the interpolation processing) (step S2 ), Pixel-shifted display is performed based on the still image frame image (step S3).

  On the other hand, if it is determined in step S1 that the movie is a moving image, then it is determined whether or not there is a scene change by comparing two consecutive frames (front and rear frames) by the scene change determination unit 5a. (Step S4). In other words, an interpolated frame image is generated by performing interpolation from the previous and next frames, but when a scene change (scene change) occurs between the previous and next frames, an interpolated frame is generated using the previous and next frames. However, it is unlikely that the generated interpolation frame will be an appropriate interpolation image. Thus, first, the presence / absence of a scene change is determined.

  If it is determined in step S4 that no scene change has occurred (the moving image changes smoothly), the motion interpolated image processing circuit 5 converts the information into two consecutive frames (front and back frames). Based on the interpolation, an interpolated frame image positioned between these two frames is generated (step S5).

  Then, pixel-shifted display corresponding to each of the moving image frames including the interpolation frame created by interpolation (for example, as shown in FIG. 5 or FIG. 6 described later) is performed (step S6).

  If it is determined in step S4 that a scene change has occurred, an interpolated frame image is not generated (step S7), as in the case where the video signal as described above is a still image. A pixel-shifted display is performed based on one frame image (step S8).

  Next, pixel shifting will be described with reference to FIG. FIG. 3 is a diagram illustrating the configuration of the pixel shifting element 10 and the state of the two-point pixel shifting.

  As shown in FIG. 3, the pixel shifting element 10 includes a polarization switching liquid crystal 11 and a birefringent plate 12 arranged in this order on the optical path from the display element 9. Note that FIG. 3 shows a configuration example for shifting two-point pixels.

  The polarization switching liquid crystal 11 does not rotate the polarization direction of the polarized light incident from the display element 9 according to the presence / absence (on / off) of the voltage applied to the polarization switching liquid crystal 11/90 °. It is a liquid crystal member capable of switching control of two states of optical rotation.

  The birefringent plate 12 shifts the pixel of polarized light of one type of polarization direction out of two types of polarized light selectively emitted from the polarization switching liquid crystal 11 and then shifts the other. This type of polarized light having a polarization direction is allowed to pass through without pixel shift. The amount of pixel shift can be set to a desired amount based on the amount of birefringence due to the material of the birefringent plate 12 and the thickness of the birefringent plate 12 in the optical axis direction. Once the setting is made, a stable pixel shift amount can be obtained.

  Here, the birefringent plate 12 is set in a crystal direction that shifts the light from the display element 9 in the horizontal direction by an amount that is 1/2 of the horizontal pixel pitch of the display element 9 (such as The birefringent plate is cut so as to be in the correct crystal direction). The birefringent plate 12 functions so as not to shift the pixel when the polarization direction of the incident light is vertical, and to shift the pixel by a ½ pixel pitch when the polarization direction of the incident light is horizontal. To do.

  The two-point pixel shift is realized by the birefringent plate 12 having such a configuration and the combination of ON / OFF of voltage application to the polarization switching liquid crystal 11.

  First, FIG. 3A shows a case where the light beam from the display element 9 goes straight and reaches the pixel position A without being shifted. This state is achieved by turning off the voltage applied to the polarization switching liquid crystal 11. That is, when the light with the horizontal polarization direction from the display element 9 reaches the polarization switching liquid crystal 11, the polarization direction is rotated by 90 ° when passing through the polarization switching liquid crystal 11 in the off state, and becomes light with a vertical polarization direction. . When the light having the perpendicular polarization direction is incident on the birefringent plate 12, it passes through without being pixel-shifted. In this way, the pixel position A is achieved.

  Next, FIG. 3B shows a case where the light beam from the display element 9 is shifted rightward and reaches the pixel position B. This state is achieved by turning on the voltage applied to the polarization switching liquid crystal 11. That is, when the light in the horizontal polarization direction from the display element 9 reaches the polarization switching liquid crystal 11, the light passes through the polarization switching liquid crystal 11 in the ON state without being rotated. When the light in the horizontal polarization direction enters the birefringent plate 12, the pixel is shifted in the horizontal right direction by a ½ pixel pitch. In this way, the pixel position B is achieved.

  By adopting such a configuration in which pixel shifting is performed in response to ON / OFF of voltage application to the polarization switching liquid crystal 11, it is not necessary to perform a mechanical operation, and pixel shifting can be performed stably. Therefore, it is considered that there are many advantages as a pixel shifting method.

  The polarization switching liquid crystal 11 can be a TN (Twisted Nematic) liquid crystal or a ferroelectric liquid crystal as long as it can perform switching control of two states of rotating the polarization direction of incident light by 90 ° or not rotating. Any type of liquid crystal may be selected. However, among these, TN liquid crystals are generally easy to obtain, inexpensive, stable in performance, and durable, and are considered to have many advantages when put to practical use.

  The birefringent plate 12 is generally made of quartz as an inexpensive material, but an anisotropic crystal such as lithium niobate (LiNbO3) may be used, and it is a colorless and transparent birefringent material. Can be widely employed (for details, see the above-mentioned Japanese Patent Application Laid-Open No. 11-296135).

  Next, a first example in which an interpolated frame image is generated and pixel-shifted display is performed will be described with reference to FIGS. 4 and 5. FIG. 4 is a diagram schematically illustrating the pixel configuration of the display element 9, and FIG. 5 is a diagram illustrating the generation of an interpolated frame image between frame images, and a moving object using a technique of shifting two pixels in the horizontal direction. It is a figure which shows the 1st example which displays a moving image at high resolution so that a motion may become smooth.

  5A is an image of the first frame, FIG. 5B is a field image of the position A generated from the image of the first frame, and FIG. 5C is generated from the image of the first frame. 5D is a field image at position A generated from the 1.5th frame interpolation frame image, FIG. 5E is a field image at position A generated from the 1.5th frame interpolation frame image, FIG. (F) is a field image at position B generated from the interpolated frame image of the 1.5th frame, FIG. 5 (G) is generated from the second frame image, and FIG. 5 (H) is generated from the second frame image. The field image at position A, FIG. 5 (I) is the field image at position B generated from the second frame image, FIG. 5 (J) is the interpolated frame image at 2.5th frame, and FIG. Generated from the interpolated frame image of the fifth frame A field image at position A, FIG. 5 (L) is a field image at position B generated from the interpolated frame image at the 2.5th frame, FIG. 5 (M) is an image at the third frame, and FIG. A field image at position A generated from the image of the frame, and FIG. 5 (O) show a field image at position B generated from the image of the third frame.

  First, as shown in FIG. 4, it is assumed that the display element 9 is configured by arranging pixels 9 a in, for example, 4 × 6 in the vertical direction.

  Then, as shown in FIGS. 5A, 5G, and 5M, the moving image data that is input and stored in the frame memory 4 has, for example, a 4 × 12 pixel configuration with a 60 Hz period. It is assumed that the image is a frame unit image (however, a moving image having no scene change). As shown in FIGS. 5A, 5G, and 5M, there is a black diagonal line that moves from left to right, for example, in the input moving image data. This is the same as the example shown in FIG.

  At this time, the motion interpolated image processing circuit 5 performs interpolation based on the frame image of FIG. 5A and the frame image of FIG. 5G, so that an interpolated frame image as shown in FIG. (Referred to as the image of the 1.5th frame), and similarly, interpolation is performed based on the frame image of FIG. 5G and the frame image of FIG. An interpolated frame image (referred to as an image of the 2.5th frame) as shown in (J) is generated. The frame image including the interpolation frame image generated in this way is an image having a 120 Hz period.

  The frame image stored in the frame memory 4 or the interpolated frame image generated by the motion interpolation image processing circuit 5 is written into the field memory 7 at a timing used for display. Therefore, the frame image or the interpolated frame image is written in the field memory 7 in the order of FIG. 5 (A), FIG. 5 (D), FIG. 5 (G), FIG. 5 (J), and FIG. become.

  When the pixel shift element 10 shifts the pixel position A by the pixel shift element 10, the pixel shift control circuit 6 has an odd pixel position in the horizontal direction from the frame image or interpolated frame image having a 4 × 12 pixel configuration written in the field memory 7. When a field image having a 4 × 6 pixel configuration is read out and supplied to the display element 9 and the pixel shift of the pixel position B is performed by the pixel shift element 10, the pixel position in the horizontal direction is an even number. A field image is read and supplied to the display element 9.

  That is, when the first frame image as shown in FIG. 5A is stored in the field memory 7, when the pixel shift of the pixel position A is performed, the 4 × 6 pixel configuration as shown in FIG. Is supplied to the display element 9, and when shifting the pixel at the pixel position B, a field image having a 4 × 6 pixel configuration as shown in FIG.

  Next, the 1.5th frame image as shown in FIG. 5D is stored in the field memory 7. In this case, when the pixel shift of the pixel position A is performed, a field image having a 4 × 6 pixel configuration as shown in FIG. 5E is supplied to the display element 9, and when the pixel shift of the pixel position B is performed, FIG. A field image having a 4 × 6 pixel configuration as shown in F) is supplied to the display element 9.

  Subsequent operations are performed in the same manner.

  Accordingly, FIG. 5B, FIG. 5C, FIG. 5E, FIG. 5F, FIG. 5H, FIG. 5I, FIG. 5K, and FIG. A field image of 240 Hz as shown in FIGS. 5N and 5O is displayed by shifting the two-point pixels in the horizontal direction.

  5 (B), FIG. 5 (C), FIG. 5 (E), FIG. 5 (F), FIG. 5 (H), FIG. 5 (I), FIG. 5 (K), FIG. Focusing on the movement of the subject (black diagonal line) in the field images of 5 (N) and FIG. 5 (O), it moves smoothly at a substantially constant speed as compared with the conventional example described with reference to FIG. You can see that it is displayed. Therefore, the line-of-sight position of the observer following the subject can also move smoothly, and is perceived as a smooth moving image display.

  By using a technology that sequentially displays field images for each pixel position for display frames including interpolation frames, both improvement of temporal resolution by generating interpolation frames and improvement of spatial resolution by shifting pixels are achieved. It becomes possible to do.

  In addition, since an interpolation frame is generated and displayed for an input frame image of 60 Hz, which is often in a normal image format, it is difficult to observe a shift in motion due to pixel shift.

  Next, a second example in which an interpolation frame image is generated and pixel-shifted display is performed will be described with reference to FIG. FIG. 6 shows a second method for generating an interpolated frame image between frame images and displaying the moving image at a high resolution so that the movement of the moving subject becomes smooth using a technique of shifting two pixels in the horizontal direction. It is a figure which shows an example. Note that here, as shown in FIG. 4, the case where the display element 9 has a 4 × 6 pixel configuration will be described as an example.

  6A shows the first frame image, FIG. 6B shows the field image at position A generated from the first frame image, and FIG. 6C shows the 1.5th interpolation frame. 6D is a field image at position B generated from the interpolated frame image of the 1.5th frame, FIG. 6E is the second frame image, and FIG. 6F is the second frame image. 6A is a field image of position A generated from the interpolation frame image of the 2.5th frame, and FIG. 6H is a field image of position B generated from the interpolation frame image of the 2.5th frame. 6I shows an image of the third frame, and FIG. 6J shows a field image at position A generated from the image of the third frame.

  The first example shown in FIG. 5 performs interpolation from a 60 Hz frame image to generate a 120 Hz frame image, and further divides each frame image into two field images to display a 240 Hz field image. However, in the second example shown in FIG. 6, a 120 Hz field image is displayed by extracting only one field image from one frame image after performing interpolation to generate a 120 Hz frame image. It has become something to do.

  First, the input moving image data is data as shown in FIGS. 6 (A), 6 (E), and 6 (I), and the above-described FIGS. 5 (A), 5 (G), Assume that they are the same as those shown in FIG.

  Then, the motion interpolation image processing circuit 5 performs interpolation based on the frame image of FIG. 6A and the frame image of FIG. 6E, so that 1.5 frames as shown in FIG. An interpolated frame image of the eye is generated, and similarly, interpolation is performed based on the frame image of FIG. 6E and the frame image of FIG. The generation of the fifth interpolation frame image is the same as in the first example described with reference to FIG.

  On the other hand, when the first frame image as shown in FIG. 6A is stored in the field memory 7, the pixel shift control circuit 6 has an odd pixel position in the horizontal direction as shown in FIG. Is supplied to the display element 9 and the pixel shift element 10 shifts the pixel position A.

  Next, when the 1.5th frame image as shown in FIG. 6C is stored in the field memory 7, the pixel shift control circuit 6 determines that the horizontal pixel position as shown in FIG. A field image having an even 4 × 6 pixel configuration is supplied to the display element 9 and the pixel shift element 10 shifts the pixel at the pixel position B.

  The operations after the second frame are performed in the same manner.

  As a result, a 120 Hz field image as shown in FIG. 6B, FIG. 6D, FIG. 6F, FIG. 6H, or FIG. Will be displayed.

  Even when focusing on the movement of the subject (black diagonal line) in the field images in FIGS. 6B, 6D, 6F, 6H, and 6J, Compared to the conventional example described with reference to FIG. 15, it can be seen that the image moves smoothly at a substantially constant speed. Therefore, the line-of-sight position of the observer following the subject can also move smoothly, and is perceived as a smooth moving image display.

  By performing such an operation, it is possible to reduce the power consumption by suppressing the image display frequency as low as 120 Hz, and to ensure the same level of time resolution as the first example described above. it can.

  Next, with reference to FIG. 7, the timing when the field image is created by the method shown in FIG. 6 and the pixel shift element 10 as shown in FIG. . Note that the timing in the method as shown in FIG. 5 is not shown. FIG. 7 is a timing chart showing the driving of the display element 9 and the polarization switching liquid crystal 11 and the pixel position when the two-point pixel is shifted.

  7A shows a switching waveform of the display element 9, FIG. 7B shows a pixel position by pixel shift, and FIG. 7C shows a switching waveform of the polarization switching liquid crystal 11. Yes.

  In the driving shown in FIG. 7, one of the two pixel positions AB is displayed at a period of 120 Hz (field period), and one period of two-point pixel shift that goes around the two pixel positions AB in order. (Frame period) is controlled to be 60 Hz.

  When the pixel shift control circuit 6 sends a field image as shown in FIG. 6B (a field image generated from the first frame image shown in FIG. 6A) to the display element 9 for display. (See FIG. 7A.) When the pixel shift control circuit 6 turns off the polarization switching liquid crystal 11 at the same timing (see FIG. 7C), the pixel position A as shown in FIG. Is displayed (see FIG. 7B).

  Next, the pixel shift control circuit 6 sends a field image as shown in FIG. 6D (a field image generated from the interpolation frame image of the 1.5th frame shown in FIG. 6C) to the display element 9. When the pixel shift control circuit 6 turns on the polarization switching liquid crystal 11 at the same timing, the display at the pixel position B is performed as shown in FIG.

  Note that the on / off switching in the drive waveform of the polarization switching liquid crystal 11 slightly precedes the display switching timing of the display element 9, but this is due to a delay in the response of the display element 9 and the polarization switching liquid crystal 11 to the control signal. This is because the drive waveform is determined in consideration of this delay because of the difference (refer to the above-mentioned JP-A-11-296135 for details).

  In the above description, the interpolated frame image is generated according to whether the input video signal is a moving image or a still image, and depending on whether a scene change has occurred even when the input video signal is a moving image. However, the present invention is not limited to this, and a switching unit for manually switching whether to generate an interpolated frame image may be provided.

  According to the first embodiment, it is possible to observe a moving image with smooth motion with high resolution.

[Embodiment 2]
8 to 14 show Embodiment 2 of the present invention, and FIG. 8 is a diagram showing the configuration of the pixel shifting element 10 and the state of 4-point pixel shifting. In the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and only different points will be mainly described.

  In the first embodiment described above, the two-point pixel shift is performed in the horizontal direction, but in the second embodiment, 2 × 2 = four-point pixel shift is performed in the horizontal and vertical directions.

  The configuration of the pixel shift display device of the present embodiment is basically the same as that shown in FIG. 1 of the first embodiment, but the operation of generating and displaying a field image, the internal configuration of the pixel shift element 10, and the like. Is different.

  That is, as shown in FIG. 8, the pixel shifting element 10 of this embodiment includes a first polarization switching liquid crystal 11a, a first birefringent plate 12a, a second polarization switching liquid crystal 11b, and a second polarization switching liquid crystal. The refracting plate 12b is arranged along the optical path along this order.

  The first birefringent plate 12a is set in a crystal direction that shifts the light from the display element 9 in the vertical direction by an amount that is ½ of the pixel pitch in the vertical direction of the display element 9. The first birefringent plate 12a shifts the pixel by 1/2 pixel pitch when the polarization direction of the incident light is vertical, and does not shift the pixel when the polarization direction of the incident light is horizontal. To work.

  The second birefringent plate 12b is set in the crystal direction so that the light from the display element 9 is shifted in the horizontal direction by an amount ½ of the horizontal pixel pitch of the display element 9. The second birefringent plate 12b shifts the pixel by 1/2 pixel pitch when the polarization direction of the incident light is horizontal, and does not shift the pixel when the polarization direction of the incident light is vertical. To work.

  The two-point pixel shift is realized by the combination of the two birefringent plates 12a and 12b having such a configuration and the on / off combination of voltage application to the two polarization switching liquid crystals 11a and 11b. That is, as described below, the combination of the polarization switching liquid crystal 11a and the birefringent plate 12a constitutes a pixel shifting element in the vertical direction, and the combination of the polarization switching liquid crystal 11b and the birefringent plate 12b is in the horizontal direction. A pixel shifting element is configured, and by further combining these two sets of pixel shifting elements, a pixel position A as shown in FIG. 8A, a pixel position B as shown in FIG. 8B, and FIG. The pixel position C as shown in FIG. 8C and the pixel position D as shown in FIG.

  First, FIG. 8A shows a case where the light beam from the display element 9 travels straight and reaches the pixel position A without being shifted. This state is achieved by turning off the applied voltage of the first polarization switching liquid crystal 11a and turning off the applied voltage of the second polarization switching liquid crystal 11b. That is, when the light in the vertical polarization direction from the display element 9 reaches the first polarization switching liquid crystal 11a, the polarization direction is rotated by 90 ° when passing through the first polarization switching liquid crystal 11a in the off state, thereby The light is polarized. When the light in the horizontal polarization direction is incident on the first birefringent plate 12a, it passes through without being shifted in pixels. Next, when the light having the horizontal polarization direction reaches the second polarization switching liquid crystal 11b, the polarization direction is rotated by 90 ° when passing through the second polarization switching liquid crystal 11b in the off state, and the light having the vertical polarization direction is rotated. It becomes light. When the light having the perpendicular polarization direction enters the second birefringent plate 12b, the light passes through without being shifted in pixels. In this way, the pixel position A is achieved.

  Next, FIG. 8B shows a case where the light beam from the display element 9 is shifted to the right and reaches the pixel position B. This state is achieved by turning off the applied voltage of the first polarization switching liquid crystal 11a and turning on the applied voltage of the second polarization switching liquid crystal 11b. That is, when the light in the vertical polarization direction from the display element 9 reaches the first polarization switching liquid crystal 11a, the polarization direction is rotated by 90 ° when passing through the first polarization switching liquid crystal 11a in the off state, thereby The light is polarized. When the light in the horizontal polarization direction is incident on the first birefringent plate 12a, it passes through without being shifted in pixels. Next, when the light having the horizontal polarization direction reaches the second polarization switching liquid crystal 11b, the light passes through the second polarization switching liquid crystal 11b in the ON state without rotating the polarization direction. When the light in the horizontal polarization direction enters the second birefringent plate 12b, the pixel is shifted in the horizontal right direction by a ½ pixel pitch. In this way, the pixel position B is achieved.

  Next, FIG. 8C shows a case where the light beam from the display element 9 is shifted downward and reaches the pixel position C. This state is achieved by turning on the applied voltage of the first polarization switching liquid crystal 11a and turning on the applied voltage of the second polarization switching liquid crystal 11b. That is, when light in the vertical polarization direction from the display element 9 reaches the first polarization switching liquid crystal 11a, it passes through the first polarization switching liquid crystal 11a in the on state without rotating the polarization direction. To do. When the light in the vertical polarization direction is incident on the first birefringent plate 12a, the pixel is shifted vertically downward by a ½ pixel pitch. Next, when the light having the perpendicular polarization direction reaches the second polarization switching liquid crystal 11b, the light passes through the second polarization switching liquid crystal 11b in the ON state without rotating the polarization direction. When the light having the perpendicular polarization direction enters the second birefringent plate 12b, the light passes through without being shifted in pixels. In this way, the pixel position C is achieved.

  FIG. 8D shows a case where the light beam from the display element 9 is shifted in the lower right direction and reaches the pixel position D. This state is achieved by turning on the applied voltage of the first polarization switching liquid crystal 11a and turning off the applied voltage of the second polarization switching liquid crystal 11b. That is, when light in the vertical polarization direction from the display element 9 reaches the first polarization switching liquid crystal 11a, it passes through the first polarization switching liquid crystal 11a in the on state without rotating the polarization direction. To do. When the light in the vertical polarization direction is incident on the first birefringent plate 12a, the pixel is shifted vertically downward by a ½ pixel pitch. Next, when the light having the perpendicular polarization direction reaches the second polarization switching liquid crystal 11b, the polarization direction is rotated by 90 ° when passing through the second polarization switching liquid crystal 11b in the off state, and the horizontal polarization direction is changed. It becomes light. When the light in the horizontal polarization direction enters the second birefringent plate 12b, the pixel is shifted in the horizontal right direction by a ½ pixel pitch. In this way, the pixel position D is achieved.

  As described above, four pixel positions A to D can be selected by a combination of on / off of voltages applied to the first polarization switching liquid crystal 11a and the second polarization switching liquid crystal 11b.

(First example)
Next, with reference to FIG. 9, the timing when the field image is created by the first method and the four-point pixel shift display is performed will be described. FIG. 9 is a timing chart showing driving and pixel positions of the display element 9, the first polarization switching liquid crystal 11a, and the second polarization switching liquid crystal 11b when the four-point pixel shift is performed by the first method. is there.

  In FIG. 9, FIG. 9A shows the switching waveform of the display element 9, FIG. 9B shows the pixel position due to pixel shift, and FIG. 9C shows the switching waveform of the first polarization switching liquid crystal 11a. FIG. 9D shows a switching waveform of the second polarization switching liquid crystal 11b.

  In the driving shown in FIG. 9, one arbitrary pixel position in each pixel position ABCD is displayed with a period (field period) of 240 Hz, and one period of four-point pixel shift that goes around the four pixel positions ABCD in order. (Frame period) is controlled to be 60 Hz.

  In this first method, the motion interpolation image processing circuit 5 generates three interpolation frame images between two consecutive frame images. That is, the motion interpolation image processing circuit 5 is based on the first frame image and the second frame image, and the first interpolation frame image (referred to as the 1.25th frame image), A second interpolation frame image (referred to as the 1.5th frame image) and a third interpolation frame image (referred to as the 1.75th frame image) are generated. Thereafter, in the same manner, based on the frame image of the second frame and the frame image of the third frame, the interpolation frame image of the 2.25th frame, the interpolation frame image of the 2.5th frame, and 2.75 frames An interpolated frame image of the eye is generated. The same applies thereafter.

  When the pixel shift control circuit 6 sends the field image at the pixel position A to the display element 9 based on the frame image of the first frame (see FIG. 9A), the pixel shift control circuit 6 By turning off the first polarization switching liquid crystal 11a at the same timing (see FIG. 9C) and turning off the second polarization switching liquid crystal 11b (see FIG. 9D), FIG. As shown, display at the pixel position A is performed (see FIG. 9B).

  Next, when the pixel shift control circuit 6 sends the field image at the pixel position B to the display element 9 based on the 1.25th interpolation frame image, the pixel shift control circuit 6 matches the timing. By turning off the first polarization switching liquid crystal 11a and turning on the second polarization switching liquid crystal 11b, the display at the pixel position B is performed as shown in FIG.

  Subsequently, when the pixel shift control circuit 6 sends the field image at the pixel position C to the display element 9 based on the 1.5th interpolation frame image, the pixel shift control circuit 6 matches the timing. By turning on the first polarization switching liquid crystal 11a and turning on the second polarization switching liquid crystal 11b, the display at the pixel position C is performed as shown in FIG.

  Further, when the pixel shift control circuit 6 sends the field image at the pixel position D to the display element 9 for display based on the 1.75th interpolated frame image, the pixel shift control circuit 6 adjusts the timing. By turning on the first polarization switching liquid crystal 11a and turning off the second polarization switching liquid crystal 11b, the display at the pixel position D is performed as shown in FIG.

  The subsequent display based on the second and subsequent frame images is the same as described above.

  As described above, the first method shown in FIG. 9 generates an interpolated frame image so as to have the same number of frame images as the number of field images corresponding to each pixel position, and generates one frame image or interpolated frame image. A field image at one pixel position is generated and displayed.

  According to the first display method, it is possible to display high resolution while obtaining smooth movement.

(Second example)
Next, with reference to FIG. 10, the timing when the field image is created by the second method and the four-point pixel shift display is performed will be described. FIG. 10 is a timing chart showing driving and pixel positions of the display element 9, the first polarization switching liquid crystal 11a, and the second polarization switching liquid crystal 11b when the four-point pixel shift is performed by the second method. is there.

  In FIG. 10, FIG. 10A shows the switching waveform of the display element 9, FIG. 10B shows the pixel position by pixel shift, and FIG. 10C shows the switching waveform of the first polarization switching liquid crystal 11a. FIG. 10D shows a switching waveform of the second polarization switching liquid crystal 11b.

  Also in the driving shown in FIG. 10, one arbitrary pixel position in each pixel position ABCD is displayed with a period of 240 Hz (field period), and one period of four-point pixel shift that goes around the four pixel positions ABCD in order. (Frame period) is controlled to be 60 Hz.

  In the second method, the motion interpolation image processing circuit 5 generates one interpolation frame image between two consecutive frame images. That is, the motion interpolation image processing circuit 5 generates one interpolation frame image (referred to as the 1.5th frame image) based on the first frame image and the second frame image. . Thereafter, similarly, an interpolated frame image of the 2.5th frame is generated based on the frame image of the second frame and the frame image of the third frame, and so on.

  When the pixel shift control circuit 6 sends the field image at the pixel position A to the display element 9 based on the frame image of the first frame (see FIG. 10A), the pixel shift control circuit 6 By turning off the first polarization switching liquid crystal 11a at the same timing (see FIG. 10C) and turning off the second polarization switching liquid crystal 11b (see FIG. 10D), FIG. As shown, display at the pixel position A is performed (see FIG. 10B).

  Next, when the pixel shift control circuit 6 sends and displays the field image at the pixel position B to the display element 9 based on the frame image of the first frame, the pixel shift control circuit 6 sets the first timing in time. By turning off the polarization switching liquid crystal 11a and turning on the second polarization switching liquid crystal 11b, display at the pixel position B is performed as shown in FIG. 8B.

  Subsequently, when the pixel shift control circuit 6 sends the field image at the pixel position C to the display element 9 based on the 1.5th interpolation frame image, the pixel shift control circuit 6 matches the timing. By turning on the first polarization switching liquid crystal 11a and turning on the second polarization switching liquid crystal 11b, the display at the pixel position C is performed as shown in FIG.

  Further, when the pixel shift control circuit 6 sends the field image at the pixel position D to the display element 9 for display based on the interpolation frame image of the 1.5th frame, the pixel shift control circuit 6 adjusts the timing. By turning on the first polarization switching liquid crystal 11a and turning off the second polarization switching liquid crystal 11b, the display at the pixel position D is performed as shown in FIG.

  The subsequent display based on the second and subsequent frame images is the same as described above.

  As described above, the second method shown in FIG. 10 generates and displays field images at two consecutive pixel positions from one frame image or interpolated frame image.

  According to the second display method, high-resolution display can be performed while obtaining a certain degree of smoothness of movement, and the load required for generating an interpolated frame image can be reduced, and the processing speed can be increased. And the price of the apparatus can be reduced.

(Third example)
Next, with reference to FIG. 11, the timing when the field image is created by the third method and the four-point pixel shift display is performed will be described. FIG. 11 is a timing chart showing driving and pixel positions of the display element 9, the first polarization switching liquid crystal 11a, and the second polarization switching liquid crystal 11b when the four-point pixel shift is performed by the third method. is there.

  In FIG. 11, FIG. 11A shows the switching waveform of the display element 9, FIG. 11B shows the pixel position by pixel shift, and FIG. 11C shows the switching waveform of the first polarization switching liquid crystal 11a. FIG. 11D shows a switching waveform of the second polarization switching liquid crystal 11b.

  In the driving shown in FIG. 11, one arbitrary pixel position in each pixel position ABCD is displayed with a period (field period) of 180 Hz, and the three consecutive pixel positions in the four pixel positions ABCD are sequentially passed. By the way, control is performed so that one frame period is 60 Hz. Therefore, the four pixel positions ABCD do not make a round in one frame period, but the timing makes a round in about 1.33 frame period.

  In the third method, the motion interpolation image processing circuit 5 generates two interpolation frame images between two consecutive frame images. That is, the motion interpolation image processing circuit 5 is based on the first frame image and the second frame image, and the first interpolation frame image (referred to as the 1.33rd frame image), A second interpolation frame image (referred to as the 1.66th frame image) is generated. Thereafter, similarly, an interpolated frame image of the 2.33th frame and an interpolated frame image of the 2.66th frame are generated based on the frame image of the second frame and the frame image of the third frame. It is the same.

  When the pixel shift control circuit 6 sends the field image at the pixel position A to the display element 9 based on the frame image of the first frame (see FIG. 11A), the pixel shift control circuit 6 By turning off the first polarization switching liquid crystal 11a at the same timing (see FIG. 11C) and turning off the second polarization switching liquid crystal 11b (see FIG. 11D), FIG. As shown, display at the pixel position A is performed (see FIG. 11B).

  Next, when the pixel shift control circuit 6 sends the field image at the pixel position B to the display element 9 based on the interpolation frame image of the 1.33th frame, the pixel shift control circuit 6 matches the timing. By turning off the first polarization switching liquid crystal 11a and turning on the second polarization switching liquid crystal 11b, the display at the pixel position B is performed as shown in FIG.

  Subsequently, when the pixel shift control circuit 6 sends the field image at the pixel position C to the display element 9 based on the 1.66th interpolation frame image, the pixel shift control circuit 6 matches the timing. By turning on the first polarization switching liquid crystal 11a and turning on the second polarization switching liquid crystal 11b, the display at the pixel position C is performed as shown in FIG.

  Further, when the pixel shift control circuit 6 sends the field image at the pixel position D to the display element 9 based on the frame image of the second frame and displays the field image, the pixel shift control circuit 6 matches the timing with the first polarization. By turning on the switching liquid crystal 11a and turning off the second polarization switching liquid crystal 11b, display at the pixel position D is performed as shown in FIG. 8D.

  Subsequent operations are similarly performed.

  As described above, the third method shown in FIG. 11 creates two interpolation frame images between two consecutive frame images, and generates a field image at one pixel position from one frame image or the interpolation frame image. Generated and displayed.

  According to the third display method, high-resolution display can be performed while obtaining a smoother movement than the second display method, and the field display rate is 240 Hz of the first display method. As a result, the power consumption can be reduced.

(Fourth example)
Next, with reference to FIG. 12, when the display element 9 is a field sequential display element, a timing when a field image is created by the above-described third method and a four-point pixel shift display is performed will be described. Here, FIG. 12 shows the driving and pixel positions of the frame sequential display element 9, the first polarization switching liquid crystal 11a and the second polarization switching liquid crystal 11b when the four-point pixel shift is performed by the third method. It is a timing chart which shows.

  In FIG. 12, FIG. 12A shows the switching waveform of the display element 9, FIG. 12B shows the pixel position by pixel shift, and FIG. 12C shows the switching waveform of the first polarization switching liquid crystal 11a. FIG. 12D shows a switching waveform of the second polarization switching liquid crystal 11b.

  The drive timing of the polarization switching liquid crystals 11a and 11b in the display method shown in FIG. 12 is the same as that in the third method shown in FIG. 11, and is continuous among the four pixel positions ABCD in one frame period (60 Hz). The display of three pixel positions (1 field period = 180 Hz) is also performed as in the third method shown in FIG.

  However, in the fourth example, RGB three-color image data is sequentially displayed on the display element 9 within one field period of 180 Hz, and although not shown, the emission color of the light source is set to RGB in synchronization with this display. Are switched sequentially.

  Accordingly, in the fourth example, the motion interpolation image processing circuit 5 generates two interpolation frame images for each of RGB colors between two consecutive frame images. That is, the motion interpolation image processing circuit 5 is referred to as a first interpolation R frame image (1.33 frame R image) based on the first frame R frame image and the second frame R frame image. And a second interpolated R frame image (referred to as the 1.66th frame R image), and based on the first frame G frame image and the second frame G frame image And generating a first interpolated G frame image (referred to as the 1.33rd frame G image) and a second interpolated G frame image (referred to as the 1.66th frame G image). Based on the B frame image of the first frame and the B frame image of the second frame, the first interpolation B frame image (referred to as the B image of the 1.33 frame) and the second interpolation B frame Generating an image (referred to as a 1.66-th frame B image). The same applies to the subsequent steps.

  While the pixel shift control circuit 6 turns off the first polarization switching liquid crystal 11a (see FIG. 12C) and turns off the second polarization switching liquid crystal 11b (see FIG. 12D), The pixel shift control circuit 6 sends the R field image at the pixel position A to the display element 9 based on the R frame image of the first frame and displays it, and then the G field image at the pixel position A based on the G frame image of the first frame. Is sent to the display element 9 for display, and then the B field image at the pixel position A is sent to the display element 9 for display based on the B frame image of the first frame (see FIG. 12A). Display of the pixel position A as shown in (A) (see FIG. 12B) is performed in the order of RGB.

  The subsequent operations such as the 1.33rd frame, the 1.66th frame, the second frame,... Are performed in the same manner.

  As described above, the third method shown in FIG. 11 can also be applied to a frame sequential display element. Here, the third method is taken as an example to explain the display by the frame sequential display element, but the first method, the second method, the method described in the first embodiment, and the like are exactly the same. Thus, it can be applied to display by a frame sequential display element.

  Next, an application example of the pixel shift display device will be described with reference to FIGS. First, FIG. 13 is a diagram illustrating a configuration example in which the pixel shift display device is applied to an HMD (head-mounted display). The configuration shown in FIG. 13 is not limited to the HMD, and is similarly applied to, for example, EVF (Electronic / View / Finder).

  The HMD main body 20 is used by being mounted in front of the eyes of the head. Since it is necessary to reduce the wearing feeling by reducing the weight as much as possible, it is essential to provide the HMD main body 20 in the HMD main body 20. It is desirable to provide outside except for the configuration. Therefore, here, for example, the pixel shift control circuit 6 is provided inside a controller or the like (not shown) provided separately.

  On the other hand, the HMD main body 20 includes a backlight 21, a display element 9, a pixel shifting element 10, an eyepiece optical system 22, a drive circuit 23, and a drive circuit 24.

  The backlight 21 illuminates the display element 9 from the back side.

  The display element 9 and the pixel shifting element 10 are as described above. Here, it is assumed that the pixel shifting element 10 has a configuration as shown in, for example, FIG.

  The eyepiece optical system 22 is for enlarging and projecting a high-resolution image emitted from the pixel shifting element 10 onto the eyes of the observer.

  The drive circuit 23 drives the display element 9 based on the control of the pixel shift control circuit 6.

  The drive circuit 24 drives the polarization switching liquid crystals 11 a and 11 b of the pixel shift element 10 based on the control of the pixel shift control circuit 6.

  Next, FIG. 14 is a diagram illustrating a configuration example in which the pixel shift display device is applied to a projector. The projector 30 shown in FIG. 14 is configured as an RGB three-plate type, and projects an image on a screen 31 for observation.

  That is, the projector 30 includes a light source unit 34, a fly-eye lens 35, a PS conversion element 36, a first dichroic mirror 37, a second dichroic mirror 38, a third dichroic mirror 39, and a mirror 40. , A mirror 41, a transmissive LCD 9r for R, a transmissive LCD 9g for G, a transmissive LCD 9b for B, a dichroic prism 42, a pixel shifting element 10, and a projection optical system 43.

  The light source unit 34 is a point light source 32 that generates white light, such as an ultra-high pressure mercury lamp, and a light beam generated from the light source 32 to form a substantially parallel light beam for irradiation in a predetermined direction. For example, a reflector 33 having a parabolic profile is provided.

  The fly-eye lens 35 is for irradiating the light from the light source unit 34 to the LCDs 9r, 9g, 9b without illumination unevenness.

  The PS conversion element 36 is for efficiently converting non-polarized light from the light source unit 34 into light having a predetermined polarization direction, and is constituted by, for example, a multi-PBS (polarized beam splitter).

  The first dichroic mirror 37 is for separating the white light from the light source unit 34 into red (R) light and other light.

  The second dichroic mirror 38 separates the light from the first dichroic mirror 37 into green (G) light and other light, and transmits the separated green (G) light to a transmission type for green (G). This is for reflection toward the LCD 9g.

  The third dichroic mirror 39 is for separating blue (B) light from the light from the second dichroic mirror 38.

  The mirror 41 is for reflecting the red (R) light from the first dichroic mirror 37 toward the red (R) transmissive LCD 9r.

  The mirror 40 is for reflecting the blue (B) light from the third dichroic mirror 39 toward the blue (B) transmissive LCD 9b.

  The R transmissive LCD 9r is for displaying the R color component of the image by controlling the passing light amount of the R light separated by the first dichroic mirror 37 based on information corresponding to the R light. .

  The transmissive LCD 9g for G is for displaying the G color component of the image by controlling the passing light amount of the G light separated by the second dichroic mirror 38 based on the information corresponding to the G light. .

  The transmissive LCD 9b for B is for displaying the B color component of the image by controlling the passing light amount of the B light separated by the third dichroic mirror 39 based on information corresponding to the B light. .

  Each of these LCDs 9r, 9g, 9b is disposed at an optically equivalent position when viewed from the projection optical system 43.

  The dichroic prism 42 includes an R color image generated by the R transmissive LCD 9r, a G color image generated by the G transmissive LCD 9g, and a B color image generated by the B transmissive LCD 9b. Is an optical path synthesizing means.

  The pixel shifting element 10 includes a polarization switching liquid crystal 11 and a birefringent plate 12. Here, it is described that the polarization switching liquid crystal 11 and the birefringent plate 12 are simply provided. However, the first and second polarization switching liquid crystals 11a and 11b and the first and second birefringence plates 12a and 12b are provided. Of course, it is possible to use a four-point pixel shift configuration.

  The projection optical system 43 is for enlarging and projecting the RGB combined image incident from the dichroic prism 42 via the pixel shifting element 10 toward the screen 31.

  Here, the case where the display element is a transmissive LCD has been described as an example. However, the present invention is not limited to this, and may be a reflective LCD (LCOS) or DMD (digital micromirror device). I do not care.

  According to the second embodiment as described above, it is possible to achieve substantially the same effect as that of the first embodiment described above even when shifting four-point pixels.

  In each of the above-described embodiments, the configuration example in which the polarization switching liquid crystal and the birefringent plate are combined as the pixel shifting element has been described. However, the present invention is not limited thereto, and is described in the above-described conventional technology. For example, the pixel may be shifted by mechanical vibration.

  Furthermore, in each of the above-described embodiments, the pixel-shifted display device has been mainly described. However, a pixel-shifted display method for performing similar processing may be used, and pixels for causing a computer to perform similar processing. A shift display program may be used.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, you may delete a some component from all the components shown by embodiment. Furthermore, the constituent elements over different embodiments may be appropriately combined. Thus, it goes without saying that various modifications and applications are possible without departing from the spirit of the invention.

  The present invention can be suitably used for a pixel shift display device, a pixel shift display method, and a pixel shift display program for generating a field image from a frame image and performing display by performing spatial pixel shift.

1 is a block diagram showing a configuration of a pixel shift display device in Embodiment 1 of the present invention. 7 is a flowchart showing a branch of processing based on each determination between a moving image / still image determination circuit and a scene change determination unit in the motion interpolation image processing circuit in the first embodiment. The figure which shows the structure of the pixel shift element in the said Embodiment 1, and the mode of a 2 point | piece pixel shift. FIG. 3 is a diagram schematically illustrating a pixel configuration of a display element in the first embodiment. In the first embodiment, the interpolated frame image between the frame images is generated, and the moving image is displayed at a high resolution so that the movement of the moving subject becomes smooth using the technique of shifting two pixels in the horizontal direction. The figure which shows the example of 1. In the first embodiment, the interpolated frame image between the frame images is generated, and the moving image is displayed at a high resolution so that the movement of the moving subject becomes smooth using the technique of shifting two pixels in the horizontal direction. The figure which shows the example of 2. 4 is a timing chart illustrating driving of the display element and the polarization switching liquid crystal and pixel positions in the two-point pixel shift in the first embodiment. The figure which shows the structure of the pixel shift element in Embodiment 2 of this invention, and the mode of a 4-point pixel shift. In the said Embodiment 2, the timing chart which shows the drive of a display element, a 1st polarization switching liquid crystal, and a 2nd polarization switching liquid crystal, and a pixel position when performing a 4-point pixel shift by the 1st method. In the said Embodiment 2, the timing chart which shows the drive of a display element, a 1st polarization switching liquid crystal, and a 2nd polarization switching liquid crystal, and a pixel position when performing 4 point | times pixel shift by the 2nd method. In the said Embodiment 2, the timing chart which shows the drive of a display element, a 1st polarization switching liquid crystal, and a 2nd polarization switching liquid crystal, and a pixel position when performing a 4-point pixel shift by the 3rd method. In the second embodiment, a timing chart showing driving and pixel positions of a surface-sequential display element, the first polarization switching liquid crystal, and the second polarization switching liquid crystal when the four-point pixel shift is performed by the third method. . The figure which shows the structural example which applied the pixel shift display apparatus to HMD (head mounted display) in the said Embodiment 2. FIG. FIG. 6 is a diagram illustrating a configuration example in which the pixel shift display device is applied to a projector in the second embodiment. The figure for demonstrating that the motion of the to-be-moved subject may become non-smooth when displaying a moving image with high resolution by the prior art using the technique of shifting two pixels in the horizontal direction.

Explanation of symbols

1 ... Pre-processing circuit (pre-processing unit)
2. Video / still image determination circuit (video / still image determination unit)
3 ... Frame memory data selector 4 ... Frame memory 5 ... Motion interpolation image processing circuit (interpolation image generation unit)
5a ... Scene change determination unit 6 ... Pixel shift control circuit (field image generation unit)
7 ... Field memory 8 ... Timing controller 9 ... Display element (display unit)
10: Pixel shift element (pixel shift section)
DESCRIPTION OF SYMBOLS 11, 11a, 11b ... Polarization switching liquid crystal 12, 12a, 12b ... Birefringent plate 20 ... HMD main body 21 ... Backlight 22 ... Eyepiece optical system 23 ... Drive circuit 24 ... Drive circuit 30 ... Projector 31 ... Screen 32 ... Light source 33 ... Reflector 34 ... Light source 35 ... Fly eye lens 36 ... PS converter 37 ... First dichroic mirror 38 ... Second dichroic mirror 39 ... Third dichroic mirror 40 ... Mirror 41 ... Mirror 42 ... Dichroic prism 43 ... Projection optics system

Claims (13)

An interpolated image generating unit that generates one or more interpolated frame images corresponding to the time between two consecutive frame images based on moving image data composed of a plurality of frame images;
A field image generation unit that generates a field image corresponding to a pixel shift position from the frame image or the interpolated frame image according to the time order of the frame image or the interpolated frame image;
A display unit for sequentially displaying the field images;
A pixel shift unit that performs spatial pixel shift according to the pixel shift position of the field image in synchronization with displaying the field image by the display unit;
A pixel-shifted display device comprising:   2. The pixel shift display device according to claim 1, wherein the field image generation unit generates one or more field images from one frame image or interpolated frame image in accordance with a pixel shift position. . Each frame image of the input moving image data further includes a pre-processing unit that performs resolution conversion so as to be the same as the apparent number of display pixels after the pixel shifting is performed by the pixel shifting unit,
The interpolated image generation unit generates an interpolated frame image having the same number of pixels as the frame image based on the frame image whose resolution has been converted by the preprocessing unit.
2. The pixel shift display device according to claim 1, wherein the field image generation unit generates a field image having the same number of pixels as the number of pixels of the display unit from the frame image or the interpolated frame image. . A moving image / still image determination unit that determines whether the input image data is moving image data or still image data;
The interpolation image generation unit is configured to stop generating an interpolation frame image when the moving image / still image determination unit determines that the image data is still image data.
The pixel shift display device according to claim 1, wherein the field image generation unit generates a field image corresponding to a pixel shift position from the still image data. A scene change determination unit for detecting whether a scene change has occurred in the input moving image data;
When the scene change determination unit determines that a scene change has occurred, the interpolated image generation unit stops generating an interpolated frame image between frames in which the scene change has occurred.
2. The pixel shift according to claim 1, wherein the field image generation unit generates a field image corresponding to a pixel shift position from one frame image between frames in which the scene change has occurred. Display device.   2. The pixel shift display device according to claim 1, further comprising a switching unit for manually switching whether or not to generate an interpolated frame image by the interpolated image generating unit. An interpolation image generation step of generating one or more interpolation frame images corresponding to the time between two consecutive frame images based on moving image data composed of a plurality of frame images;
A field image generation step of generating a field image corresponding to a pixel shift position from the frame image or the interpolated frame image according to the time order of the frame image or the interpolated frame image;
A display step for sequentially displaying the field images;
A pixel shifting step of performing spatial pixel shifting according to the pixel shifting position of the field image in synchronization with displaying the field image by the display step;
A pixel-shifted display method characterized by comprising:   8. The pixel shift display method according to claim 7, wherein the field image generation step is a step of generating one or more field images according to a pixel shift position from one frame image or an interpolated frame image. . Each frame image of the input moving image data further includes a pre-processing step for performing resolution conversion so as to be the same as the apparent number of display pixels after the pixel shifting is performed by the pixel shifting step,
The interpolated image generation step is a step of generating an interpolated frame image having the same number of pixels as the frame image based on the frame image subjected to resolution conversion in the preprocessing step.
8. The field image generation step is a step of generating a field image having the same number of pixels as the number of pixels of the image displayed by the display step from the frame image or the interpolated frame image. Pixel shift display method. A moving image / still image determination step for determining whether the input image data is moving image data or still image data;
The interpolation image generation step includes a step of stopping the generation of the interpolated frame image when it is determined by the moving image / still image determination step that the image is still image data,
8. The pixel shift display method according to claim 7, wherein the field image generation step is a step of generating a field image corresponding to a pixel shift position from the still image data. A scene change determination step for detecting whether or not a scene change has occurred in the input moving image data;
The interpolated image generation step includes a step of stopping generation of an interpolated frame image between frames in which the scene change has occurred when it is determined in the scene change determining step that a scene change has occurred. The pixel-shifted display method according to claim 7.   8. The pixel shift display method according to claim 7, wherein the interpolation image generation step includes a step of switching whether or not to generate an interpolation frame image according to a manual operation. On the computer,
An interpolation image generation step of generating one or more interpolation frame images corresponding to the time between two consecutive frame images based on moving image data composed of a plurality of frame images;
A field image generation step of generating a field image corresponding to a pixel shift position from the frame image or the interpolated frame image according to the time order of the frame image or the interpolated frame image;
A display step for sequentially displaying the field images;
A pixel shifting step of performing spatial pixel shifting according to the pixel shifting position of the field image in synchronization with displaying the field image by the display step;
Pixel shift display program to execute.

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