JP2010016463A - Image display device - Google Patents

Abstract

An object of the present invention is to provide an image display device that performs FRC processing by motion compensation when performing multi-view display, thereby improving moving image response and improving image quality.
An image display device simultaneously displays a plurality of images corresponding to one of a plurality of viewing angles within one frame, and each position within the plurality of viewing angles is a position within another viewing angle. A liquid crystal display 16 capable of visually recognizing different images, an FRC unit 10 for converting the number of frames by interpolating an image signal subjected to motion compensation processing between frames of the input image signal, and one frame to be displayed on the liquid crystal display 16 And a control unit 14 that outputs a control signal for notifying the number of images to the FRC unit 10. The FRC unit 10 configures a motion vector detection range for each image in one frame based on the control signal output from the control unit 14, and detects a motion vector in the configured motion vector detection range.
[Selection] Figure 3

Description

  The present invention relates to an image display device, and more particularly to an image display device having a multi-view display function such as dual view.

  Conventionally, by arranging a layer called a parallax barrier on the surface of a liquid crystal display panel, even when viewing the screen of the same liquid crystal display panel, the images seen from the right and the left are different. A dual view display that can be used is known (see, for example, Patent Document 1).

  The parallax barrier is a filter having a large number of transparent slits separated by an opaque region, whereby the direction of light from the backlight can be separated into left and right. Accordingly, if different image data is output for each adjacent pixel or plural pixels according to the width and interval of the transparent slit of the parallax barrier, each image data can be separated by the parallax barrier. Thus, the display image can be made different depending on whether the viewer sees from the right or the left.

In other words, the dual view display simultaneously displays two images corresponding to one of the two viewing angles, such as left and right or up and down, at different positions within the two viewing angles and different from the positions within the other viewing angle. It is comprised so that an image can be visually recognized.
In addition to the dual view display that simultaneously displays the two images as described above, there is also a triple view display that can simultaneously display three images that can be viewed within three different viewing angles such as left, middle, and right. Proposed. Here, a display that simultaneously displays a plurality of images that can be viewed within the plurality of viewing angles is a multi-view display, and the display screen is a multi-view screen.

  FIG. 6 is a diagram for explaining the basic principle of the dual view display, in which 100 denotes a liquid crystal display. In a liquid crystal display 100 capable of dual view display, a parallax barrier (parallax barrier) 100b is disposed on the entire surface of a liquid crystal display panel 100a having a plurality of pixels A and B. The parallax barrier 100b is a screen having a plurality of vertical translucent slits separated by opaque regions. The light transmitted through the pixel A of the liquid crystal display panel 100a reaches the viewer II side located at a predetermined viewing angle with respect to the display surface of the liquid crystal display panel 100a through the light-transmitting slits of the parallax barrier 100b. That is, different images displayed on the liquid crystal display panel 100a can be seen only from a predetermined area in the space by the plurality of light-transmitting slits of the parallax barrier 100b. Thus, the viewer I and the viewer II can see different images.

  On the other hand, in order to improve motion blur in a hold-type display method such as a liquid crystal display device, a technique for converting a frame rate (the number of frames) by interpolating an image between frames is known. This technique is called FRC (Frame Rate Converter) and is put into practical use in liquid crystal display devices and the like.

For example, Patent Document 2 describes a technique for improving a reduction in spatial frequency characteristics that causes motion blur by increasing the frame frequency of a display image by generating an interpolation frame adaptively in motion. ing. In this method, at least one interpolated image signal to be interpolated between frames of a display image is formed in a motion adaptive manner from the preceding and following frames, and the formed interpolated image signal is interpolated between frames and sequentially displayed. ing.
JP 2005-84414 A Japanese Patent No. 3295437

  When the FRC process by motion compensation is performed in the above-described dual view display, since adjacent pixels are different images as shown in FIG. 6, if the motion compensation process is performed on such an image, an appropriate motion is obtained. There was a problem that the vector could not be detected, and the interpolated image broke down.

  In order to avoid this, when FRC processing is performed in a conventional dual view display, an interpolated image based on a motion vector is not generated, and an original image is output twice by an on / off signal. This will be described with reference to FIGS.

  FIG. 7 is a block diagram for explaining FRC processing in a conventional dual view display, in which 101 denotes an image processing unit, 102 denotes an FRC unit, 103 denotes a liquid crystal controller, and 104 denotes a control unit. When the dual view mode is selected based on a user operation or the like, two original images of image A and image B are input to the image processing unit 101. The image processing unit 101 generates an image signal in which the pixel of the image A and the pixel of the image B are adjacent to each other in order to display the image A and the image B in dual view on one screen (one frame).

  Then, the image processing unit 101 outputs an image signal obtained by combining the image A and the image B to the FRC unit 102 and outputs a dual view display identification signal to the control unit 104. The control unit 104 outputs an on / off signal for invalidating the motion compensation processing to the FRC unit 102 in response to the dual view display identification signal from the image processing unit 101. The FRC unit 102 invalidates the motion compensation processing in accordance with the on / off signal from the control unit 104, outputs the original image twice, and outputs an image signal obtained by converting the frame rate to the liquid crystal controller 103. The liquid crystal controller 103 outputs the image signal output from the FRC unit 102 to the liquid crystal display 100 of FIG. 6 and causes the liquid crystal display 100 to display images A and B in a dual view.

  FIG. 8 is a diagram for explaining frame rate conversion processing by the FRC unit 102 of the conventional dual view display. 8A shows an input frame of the FRC unit 102, and FIG. 8B shows an output frame of the FRC unit 102. Thus, the input frames f1 and f2 from the image processing unit 101 are subjected to frame rate conversion by the FRC unit 102. That is, the FRC unit 102 performs the frame rate conversion by outputting the input frames f1 and f2 twice without performing the motion compensation process between the input frames f1 and f2.

  However, in the multi-view display, the method of simply outputting the same frame twice as described above causes unnatural motion (jerkiness, judder, etc.) due to frame rate conversion, and is insufficient in image quality. It was something.

  The present invention has been made in view of the above-described circumstances, and an image display device that performs FRC processing by motion compensation when performing multi-view display to improve moving image response and improve image quality. The purpose is to provide.

  In order to solve the above-described problem, the first technical means of the present invention displays a plurality of images corresponding to any of a plurality of viewing angles simultaneously in one frame or in one field, and within the plurality of viewing angles. An image display device provided with display means capable of visually recognizing an image different from a position within another viewing angle at each position, and an image subjected to motion compensation processing between frames or fields of an input image signal By interpolating the signal, the number of frames or fields of the input image signal is converted and output to the display means, and the number of images in one frame or one field displayed on the display means is determined. Control means for outputting a control signal for notification to the rate conversion means, the rate conversion means based on the control signal output by the control means 1 frame or motion for each image in one field constitute a detection range of the vector is obtained by and detecting a motion vector detection range of the motion vector the structure.

  According to the second technical means, in the first technical means, when the number of images notified by the control signal is n (n ≧ 2), the rate converting means may be within one frame of the input image signal or 1 With respect to the viewing angle direction of each image in the field, pixels are extracted every n-1 pixels, and a motion vector detection range is configured by the extracted pixels.

  According to a third technical means, in the second technical means, the viewing angle direction of each image is a horizontal direction or a vertical direction in one frame or one field.

  A fourth technical means is the motion vector according to any one of the first to third technical means, wherein the rate conversion means detects motion vector information between consecutive frames or fields included in the input image signal. A detection unit; an interpolation vector allocating unit that allocates an interpolation vector between the frames or between the fields based on the detected motion vector information; and an interpolation that generates an interpolation image signal from the allocated interpolation vector. An image generation unit and an image interpolation unit for interpolating the generated interpolated image signal between the frames or between the fields are provided.

  According to the present invention, when performing multi-view display, FRC processing by motion compensation can be performed, so that moving image response can be improved and image quality can be improved.

  Hereinafter, preferred embodiments of an image display device according to the present invention will be described with reference to the accompanying drawings. The image display device according to the present embodiment includes a dual view display function and an FRC function. Although the present invention can be applied to any of a field signal, an interpolated field signal, a frame signal, and an interpolated frame signal, both (field and frame) are in a similar relationship with each other, so A signal and an interpolated frame signal will be described as representative examples.

  FIG. 1 is a block diagram illustrating a configuration example of a motion compensated frame rate conversion unit included in the image display apparatus of the present invention. In the figure, reference numeral 10 denotes a frame rate conversion unit (hereinafter referred to as FRC unit), which corresponds to the rate conversion means of the present invention and detects a motion vector between two consecutive frames included in an input image signal. And a frame generation unit 12 that generates an interpolation frame (interpolated image) based on the detected motion vector. In addition, although the vector detection part 11 shows about the example at the time of using an iterative gradient method for a motion vector detection, it is not limited to this iterative gradient method, A block matching method etc. may be used.

  Here, the feature of the iterative gradient method is that a motion vector can be detected in units of blocks, so that several types of motion amounts can be detected, and a motion vector can be detected even in a small-sized moving object. Also, the circuit configuration can be realized on a small scale as compared with other methods (block matching method or the like). In this iterative gradient method, a method is used in which the gradient method is repeated for the detected block, using the motion vector of a nearby block that has already been detected as an initial displacement vector, and starting from this. According to this method, it is possible to obtain an almost accurate motion amount by repeating the gradient method about twice.

  In FIG. 1, a vector detection unit 11 limits a high frequency band by multiplying an extracted Y signal by LPF and a luminance signal extraction unit 11a that extracts a luminance signal (Y signal) from an input image signal (RGB signal). A preprocessing filter 11b for performing the motion detection, a frame memory 11c for motion detection, an initial vector memory 11d for storing initial vector candidates, and a motion vector detection unit 11e for detecting a motion vector between frames using an iterative gradient method. And an interpolation vector evaluation unit 11f that allocates an interpolation vector between frames based on the detected motion vector.

  Since the calculation of the iterative gradient method uses the differential component of the pixel, it is easily affected by noise, and the calculation error increases if the amount of change in the gradient in the detection block is large. To limit the high-frequency band. In the initial vector memory 11d, motion vectors (initial vector candidates) already detected in the previous frame are stored as initial vector candidates.

  The motion vector detection unit 11e selects a motion vector closest to the motion vector of the detected block from among the initial vector candidates stored in the initial vector memory 11d as an initial vector. That is, the initial vector is selected by the block matching method from the already detected motion vectors (initial vector candidates) in the blocks near the detected block. Then, the motion vector detection unit 11e detects a motion vector between the previous frame and the current frame by gradient method calculation with the selected initial vector as a starting point.

  The interpolation vector evaluation unit 11f corresponds to the interpolation vector allocation unit of the present invention, evaluates the motion vector detected by the motion vector detection unit 11e, and determines an optimal interpolation vector between frames based on the evaluation result. It is allocated to the interpolation block and output to the frame generation unit 12.

  The frame generation unit 12 includes an interpolation frame memory 12a for accumulating two input frames (previous frame and current frame), two input frames from the interpolation frame memory 12a, and an interpolation vector evaluation unit 11f. An interpolation frame generation unit 12b for generating an interpolation frame based on the interpolation vector of time, a time base conversion frame memory 12c for storing input frames (previous frame, current frame), and a time base conversion frame A time base conversion unit 12d that inserts the interpolation frame from the interpolation frame generation unit 12b into the input frame from the memory 12c.

  The interpolation frame generation unit 12b corresponds to the interpolation image generation unit of the present invention, and the time base conversion unit 12d corresponds to the image interpolation unit of the present invention.

  FIG. 2 is a diagram for explaining an example of the interpolation frame generation processing by the frame generation unit 12. The interpolation frame generation unit 12b extends the interpolation vector V assigned to the interpolation block to the previous frame and the current frame, and interpolates each pixel in the interpolation block using pixels near the intersection with each frame. . For example, in the previous frame, the luminance of point A is calculated from three points in the vicinity. In the current frame, the luminance of point B is calculated from the three neighboring points. In the interpolated frame, the luminance at point P is interpolated from the luminance at points A and B. The brightness at point P may be the average of the brightness at point A and the brightness at point B, for example.

  The interpolated frame generated as described above is sent to the time base converter 12d. The time base conversion unit 12d performs a process of converting the frame rate by inserting an interpolation frame between the previous frame and the current frame. As described above, the FRC unit 10 can convert the input image signal (60 frames / second) into the motion compensated output image signal (120 frames / second), and outputs this to the display panel, thereby reducing motion blur. It is possible to reduce and improve the video quality. Here, a case where the frame rate conversion of an input image signal of 60 frames / second to an output image signal of 120 frames / second is described, but for example, output image signals of 90 frames / second and 180 frames / second are obtained. Needless to say, it may be applied to a case.

  FIG. 3 is a block diagram showing a configuration example of a main part of the image display apparatus according to the present invention, in which 13 denotes an image processing unit, 14 denotes a control unit, 15 denotes a liquid crystal controller, and 16 denotes a liquid crystal display. The FRC unit 10 includes a motion vector detection unit 11e, an interpolation frame memory 12a, an interpolation frame generation unit 12b, a motion vector detection block calculation unit 11g, and a frame memory control unit 12e. Here, only the main configuration according to the present invention is illustrated, and the luminance signal extraction unit 11a, the preprocessing filter 11b, the motion detection frame memory 11c, the initial vector memory 11d, and the interpolation vector evaluation unit 11f illustrated in FIG. Description of the time base conversion frame memory 12c and the time base conversion unit 12d is omitted.

  The image display device (hereinafter, represented by a liquid crystal display device) in the present embodiment displays a plurality of images corresponding to any one of a plurality of viewing angles simultaneously within one frame or one field, and within a plurality of viewing angles. Corresponding to a liquid crystal display 16 corresponding to a display means capable of visually recognizing an image different from a position within another viewing angle at each position, and a rate conversion means for converting the frame rate by motion compensation and outputting it to the liquid crystal display 16 The FRC unit 10 is provided.

  In FIG. 3, when the dual view mode is selected based on a user operation or the like, two original images of an image A and an image B are input to the image processing unit 13. The image processing unit 13 generates an image signal in which the pixel of the image A and the pixel of the image B are adjacent to each other in order to display the image A and the image B in dual view on one screen (one frame). Here, a case where the image A and the image B are separated and displayed in the left and right (horizontal) directions will be described as an example.

  The image processing unit 13 outputs an image signal (input frame) obtained by combining the image A and the image B to the FRC unit 10 and outputs a dual view display identification signal to the control unit 14. The control unit 14 outputs a control signal to the FRC unit 10 in response to the dual view display identification signal from the image processing unit 13. This control signal is a signal for notifying the number of images in one frame or one field to be displayed on the liquid crystal display 16. In the FRC unit 10, the input frame from the image processing unit 13 is input to the motion vector detection block calculation unit 11g and the interpolation frame memory 12a. A control signal from the control unit 14 is input to the motion vector detection block calculation unit 11g and the frame memory control unit 12e.

  The motion vector detection block calculation unit 11g configures a motion vector detection range (motion vector detection block) for each image within one frame or one field in accordance with a control signal from the control unit. Specifically, when the number of images notified by the control signal is n (n ≧ 2), the motion vector detection block calculation unit 11g has the viewing angle of each image within one frame or one field of the image signal. A pixel is extracted every n-1 pixels with respect to the direction (horizontal direction or vertical direction), and a motion vector detection block is configured by the extracted pixels. For example, if the number of images n is 2, pixels are extracted every other pixel in the horizontal direction, and if the number of images n is 3, pixels are extracted every two pixels in the horizontal direction.

  FIG. 4 is a diagram for explaining an example of a method of configuring a motion vector detection block when the number of images n = 2. In this example, since the viewing angle direction (the direction of the arrow in the figure) of each image (images A and B) in the frame is the horizontal (left and right) direction, n−1 pixels (n is the horizontal direction in the frame). Pixels are extracted every (number of images in one frame). When the number n of images in one frame is 2 (images A and B), a motion vector detection block is configured for two consecutive input frames f1 and f2. Here, by extracting pixels every other pixel in the horizontal direction of the input frame f1 serving as the previous frame, a detection block b1 composed of the pixel A1 of the image A is configured, and similarly, the input frame serving as the current frame. By detecting pixels every other pixel in the horizontal direction of f2, a detection block b2 including the pixel A2 of the image A is configured. The same applies to the pixels B1 and B2 of the image B. The size of the motion vector detection block is arbitrary, but may be set in advance, for example, ± 20 pixels in the horizontal direction and ± 10 pixels in the vertical direction.

  The motion vector detection unit 11e detects a motion vector using the motion vector detection block configured by the motion vector detection block calculation unit 11g as a motion vector search range.

  Hereinafter, although it is the same as the processing shown in FIG. 1, the interpolation vector evaluation unit 11f evaluates the motion vector detected by the motion vector detection unit 11e, and the optimal interpolation vector is framed based on the evaluation result. It assigns to the interpolated block between and outputs to the interpolated frame generation unit 12b. The interpolation frame generation unit 12b generates an interpolation frame based on the two input frames from the interpolation frame memory 12a and the interpolation vector from the interpolation vector evaluation unit 11f.

  Here, a control signal from the control unit 14 is input to the frame memory control unit 12e. For example, when a control signal (number of images n = 2) is input, the frame memory control unit 12e reads two input frames from the interpolation frame memory 12a and outputs them to the interpolation frame generation unit 12b.

  Finally, the time base conversion unit 12d inserts the interpolation frame from the interpolation frame generation unit 12b into the input frame from the time base conversion frame memory 12c, and sends the image signal after the frame rate conversion to the liquid crystal controller 15. Output.

  The control unit 14 includes a CPU, a memory, and the like for controlling each unit (the FRC unit 10, the image processing unit 13, the liquid crystal controller 15, and the liquid crystal display 16) illustrated in FIG. 3, and controls the FRC processing in the FRC unit 10. .

  The liquid crystal controller 15 generates a display timing signal necessary for the liquid crystal display 16 under the control of the control unit 14. In addition, the liquid crystal controller 15 processes the image signal output from the FRC unit 10 so that the pixel distribution is suitable for dual view display, and outputs the processed image signal to the liquid crystal display 16 as one image data. At this time, the liquid crystal controller 15 also outputs a display control signal necessary for controlling the display operation of the liquid crystal display 16. Specifically, the liquid crystal controller 15 drives the scan electrode by the gate driver of the liquid crystal display 16 based on the image data converted by the FRC unit 10 and drives the data electrode by the source driver.

  The liquid crystal display 16 is illuminated from the back by light from a backlight (not shown). An image is displayed by adjusting the amount of illumination light transmitted through the substrate in accordance with the strength of the electric field applied to the liquid crystal layer having an anisotropic dielectric constant injected between the two substrates. Further, the above-described parallax barrier (parallax barrier) is superimposed on the front surface of the liquid crystal display 16. The parallax barrier is a screen having a plurality of vertical translucent slits separated by opaque regions.

  Here, when the dual view display is performed on the liquid crystal display 16, for example, adjacent pixels of the liquid crystal display 16 are driven according to the image data for the right viewer and the image data for the left viewer, respectively. You can do it. In other words, adjacent pixels are driven according to image data for different directions. It should be noted that every other pixel may be driven in accordance with different image data, or may be driven every plural number such as every second or every third pixel. In this case, display pixels for image data may be set according to the width of the translucent slit of the parallax barrier.

  That is, the pixels of the liquid crystal display 16 are driven based on the display control signal from the liquid crystal controller 15. As a result, the light that can be seen through the plurality of translucent slits of the parallax barrier can only be seen from a prescribed region in space. For example, the right viewer can view an image corresponding to the right viewer image data, and the left viewer can view an image corresponding to the left viewer image data.

  As described above, when multi-view display such as dual view is performed, FRC processing by motion compensation can be performed, so that it is possible to improve moving image response and improve image quality.

  FIG. 5 is a diagram for explaining an example of frame rate conversion processing by the FRC unit 10 of the dual view display according to the present invention. FIG. 5A shows an input frame of the FRC unit 10, and FIG. 5B shows an output frame of the FRC unit 10. As described above, the input frame from the image processing unit 11 is subjected to frame rate conversion by the FRC unit 10. That is, the FRC unit 10 performs a motion compensation process between the input frames f1 and f2, outputs an interpolation frame f1 ', and similarly performs a motion compensation process between the input frames f2 and f3, f2 'is output. Thus, the frame rate is converted by interpolating the image signal subjected to the motion compensation process between the previous frame and the current frame.

  In the above description, the example in which pixels are extracted every other pixel in the horizontal direction in the frame has been described. However, when the viewing angle direction of each image in the frame is the vertical (vertical) direction, the frame is extracted. Pixels may be extracted every n-1 pixels (n is the number of images in one frame) in the vertical (up and down) direction. In this case, the pixels A1, A2,... Of the image A and the pixels B1, B2,... Of the image B are respectively arranged in the horizontal direction in the frame, and one screen is visually recognized as an image that differs in the vertical direction according to the position within the viewing angle. Is done. The parallax barrier may be a screen having a plurality of horizontal translucent slits separated by an opaque region.

It is a block diagram which shows the structural example of the motion compensation type frame rate conversion part with which the image display apparatus of this invention is provided. It is a figure for demonstrating an example of the interpolation frame production | generation process by a frame production | generation part. It is a block diagram which shows the principal part structural example of the image display apparatus which concerns on this invention. It is a figure for demonstrating an example of the structure method of the motion vector detection block at the time of setting the number of images n = 2. It is a figure for demonstrating an example of the frame rate conversion process by the FRC part of the dual view display by this invention. It is a figure for demonstrating the basic principle of a dual view display. It is a block diagram for demonstrating the FRC process in the conventional dual view display. It is a figure for demonstrating the frame rate conversion process by the FRC part of the conventional dual view display.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Frame rate conversion (FRC) part, 11 ... Vector detection part, 11a ... Luminance signal extraction part, 11b ... Pre-processing filter, 11c ... Frame memory for motion detection, 11d ... Initial vector memory, 11e ... Motion vector detection part, 11f: Interpolation vector evaluation unit, 11g: Motion vector detection block calculation unit, 12 ... Frame generation unit, 12a ... Interpolation frame memory, 12b ... Interpolation frame generation unit, 12c ... Time base conversion frame memory, 12d ... Time base conversion unit, 12e ... frame memory control unit, 13 ... image processing unit, 14 ... control unit, 15 ... liquid crystal controller, 16 ... liquid crystal display.

Claims (4)

A plurality of images corresponding to one of a plurality of viewing angles are simultaneously displayed in one frame or one field, and an image different from a position in another viewing angle is visually recognized at each position within the plurality of viewing angles. An image display device provided with possible display means,
Rate conversion means for converting the number of frames or fields of the input image signal and interpolating between the frames or fields of the input image signal and interpolating the number of frames or fields of the input image signal and outputting to the display means; ,
Control means for outputting a control signal for notifying the number of images in one frame or one field to be displayed on the display means to the rate conversion means;
The rate conversion means configures a motion vector detection range for each image within one frame or one field based on the control signal output by the control means, and moves within the motion vector detection range thus configured. An image display device characterized by detecting a vector.   2. The image display device according to claim 1, wherein when the number of images notified by the control signal is n (n ≧ 2), the rate conversion means is within one frame or one field of the input image signal. An image display device, wherein pixels are extracted every n-1 pixels with respect to the viewing angle direction of each of the images, and a motion vector detection range is configured by the extracted pixels.   3. The image display device according to claim 2, wherein a viewing angle direction of each image is a horizontal direction or a vertical direction within one frame or one field.   4. The image display device according to claim 1, wherein the rate conversion unit includes a motion vector detection unit that detects motion vector information between consecutive frames or fields included in the input image signal. 5. An interpolation vector allocating unit that allocates an interpolation vector between the frames or between the fields based on the detected motion vector information, and an interpolation image generating unit that generates an interpolation image signal from the allocated interpolation vector And an image interpolating unit for interpolating the generated interpolated image signal between the frames or between the fields.

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