JP2012227799A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device in which frame interpolation is carried out depending on the type of an input image or the wish of a user.SOLUTION: The image display device comprises: a frame rate determination unit 5 which determines a frame rate of a video signal input externally, and detects pull-down; a pull-down reverse conversion unit 2 which performs pull-down reverse conversion of a progressive signal when the frame rate determination unit 5 determines that an input video signal is a progressive signal produced from a video signal of 24 frames/sec by 2-3 pull-down processing and outputs a reverse converted video signal of 24 frames/sec; a selector 9 which selects any one of the input video signal or the reverse converted video signal according to the external operation input; and a frame interpolation unit 4 which enhances the frame rate by inserting an interpolation frame between the original frames of the video signal selected by the selector 9.

Description

  The present invention relates to an image display device, and more particularly to an image display device that displays a video signal at a high speed drive such as 120 frames / second or 240 frames / second.

  Conventionally, liquid crystal panels are driven at 60 frames / second, but recently, liquid crystal panels that are driven at 120 frames / second (double speed) or 240 frames / second (four times speed) have appeared. Therefore, image display devices such as projectors are also required to cope with this. For example, intermediate frame images are generated from continuous frame images, that is, frame interpolation is performed, and signals of 120 frames / second or signals of 240 frames / second are obtained. Is generated.

  As a method of interpolating an intermediate image frame between image frames of an input video signal, for example, in Patent Document 1, a black insertion process for inserting a black frame, or an intermediate image frame (based on two adjacent image frames F1 and F2) A method of generating F1 + F2) / 2 is disclosed.

JP 2009-58785 A

  However, when a progressive signal obtained by pulling down 2-3 frames of a 24 frames / second film image to a 30 frames (60 fields) / second moving image becomes an input image, interpolation is performed based on two adjacent image frames in image processing. If this is done, the motion of the moving image recorded at the original 24 frames / second may be impaired. In other words, the movements peculiar to film images are averaged and lost.

  In addition, in order to generate an intermediate frame based on two adjacent frames, it is necessary to store the video in the memory and then perform video processing, so that a delay occurs between the input signal and the display video. . For example, in the case of content that requires immediate operation after visually recognizing a video, such as a shooting game or remote operation, a delay as described above is a fatal problem.

  An object of the present invention is to provide an image display device that performs frame interpolation in accordance with the type of input video and the desire of a user.

  The image display apparatus according to the present invention includes a frame rate determination unit that performs frame rate determination and pull-down detection of an input video signal input from the outside, and the input video signal is processed by 2-3 pull-down from a video signal of 24 frames / second. When the frame rate determination unit determines that the signal is a progressive signal, a pull-down inverse conversion unit that performs a pull-down inverse conversion on the progressive signal and outputs a 24 frame / second inverse-conversion video signal, and an external operation input And a selector that selects either the input video signal or the inversely converted video signal, and a frame interpolation unit that inserts an interpolation frame between the original frames of the video signal selected by the selector to improve the frame rate.

  The image display apparatus according to the present invention is configured so that when the frame rate determination unit determines that the input video signal is a progressive signal obtained by performing 2-3 pulldown processing from a video signal of 24 frames / second, a pulldown reverse is applied to the progressive signal. A pull-down inverse conversion unit that performs conversion and outputs an inversely converted video signal of 24 frames / second, a selector that selects either the input video signal or the inversely converted video signal according to an external operation input, and a selector selected It has a frame interpolation unit that inserts an interpolated frame between the original frames of the video signal to improve the frame rate, so the user's desire to perform normal conversion or conversion that preserves the feeling of movie film video It can be selected according to.

It is a block diagram which shows the structure of the image display apparatus of this invention. It is a conceptual diagram which shows the frame rate conversion process of the input video signal by which pull-down conversion was carried out. It is a conceptual diagram which shows the frame rate conversion process of an input video signal of 24 fps. It is a conceptual diagram which shows the double speed conversion process from 60 fps to 120 fps.

(Embodiment 1)
<Configuration>
FIG. 1 is a block diagram showing the configuration of the image display apparatus of the present invention. The image display apparatus 1 includes a video input unit 10 to which a video signal is input from the outside, a pull-down inverse conversion unit 2, a selector 9, a frame interpolation unit 4, a frame memory 3, a frame rate determination unit 5, a control unit 6, An image display unit 7 and an operation unit 8 are provided.

  The pull-down inverse conversion unit 2 temporarily stores the video signal received from the video input unit 10 in the frame memory 3. The frame rate determination unit 5 performs frame rate determination and pull-down detection on the video signal stored in the frame memory 3. That is, it is determined whether or not the video signal of 24 frames per second is a 2-3 pulldown video signal, and the determination result is output to the control unit 6. The control unit 6 controls the pull-down inverse conversion unit 2 and the selector 9 based on the determination result of the frame rate determination unit 5. Upon receiving an instruction from the operation unit 8, the control unit 6 can control the pull-down inverse conversion unit 2, the selector 9, and the frame interpolation unit 4 synchronously or independently.

  When the frame rate determination unit 5 determines that the video signal stored in the frame memory 3 is a video signal that has been pulled down 2-3 from the video signal of 24 frames per second, the pull-down inverse conversion unit 2 And the video signal frame rate is inversely converted to the state before pull-down. This operation is performed under the control of the control unit 6 that receives the determination result of the frame rate determination unit 5.

  The inversely converted video signal (inversely converted video signal) is sent from the pull-down inverse conversion unit 2 to the selector 9. Further, the input video signal is directly sent from the video input unit 10 to the selector 9, and the selector 9 selects either the inversely converted video signal or the input video signal and sends it to the frame interpolation unit 4. Here, the selector 9 is controlled by the control unit 6 that has received a user operation from the operation unit 8, and the user inputs an instruction to the operation unit 8 to cause the selector 9 to select a desired video signal. Is possible.

  The frame interpolation unit 4 inserts an interpolation frame between the original frames of the video signal to improve the frame rate to 120 frames / second or 240 frames / second. Here, what kind of interpolation frame is inserted is controlled by the control unit 6 that has received a user operation from the operation unit 8, and the user inputs an instruction to the operation unit 8, whereby the frame interpolation unit 4 is inserted. Can perform a desired interpolation operation.

  The video signal improved to a predetermined frame rate by the frame interpolation unit 4 is sent to the image display unit 7 to display an image.

<Operation>
FIG. 2 (1) shows a video signal of 30 frames (60 fields) per second used for normal television broadcasting. In the figure, six fields from A to F arranged at 1/60 second intervals are shown.

  On the other hand, a movie film or the like records video at 24 frames per second. In such a movie signal, as shown in FIG. 2 (2), frames A, B, C,. Be placed. This video signal is subjected to 2-3 pull-down processing to convert it into an interlace signal of 30 frames per second, and the progressive-converted video signal is shown in FIG. As shown in the figure, the third frame is composed of A and B. Thus, two different fields (originally two consecutive frames) are mixed at a rate of 1 frame per 5 frames, thus 1 frame. Will be configured.

  Therefore, in the video signal subjected to such pull-down processing, when an interpolation frame is formed from adjacent frames before and after and double-speed frame conversion is performed to 120 frames per second, as shown in FIG. A and B are mixed over the sixth frame. As a result, the switching from the frame A to the frame B is different from the original video signal, and the video feeling peculiar to the movie is lost.

  Therefore, in the image display device 1 of the present embodiment, when the input video signal is a progressive signal (60 frames per second) pulled down 2-3 from the video signal of 24 frames per second, the pull-down inverse conversion unit 2 performs FIG. The frame interpolation unit 4 performs frame interpolation after returning to the video signal of 24 frames per second before 2-3 pulldown shown in 2). FIG. 2 (5) shows a video signal of 120 frames per second created by repeating the original frame four times. This makes it possible to perform double speed conversion while faithfully reproducing the motion of the movie content. When converting to 240 frames per second, the number of frame repetitions is doubled.

  Note that even if the input video signal is a progressive signal obtained by pulling down 2-3 video signals from 24 frames per second, the frame interpolation shown in FIG. 2 (5) may be performed as it is. In this case, when a user operation is input to the operation unit 8, the control unit 6 controls the selector 9 according to the operation, and the selector 9 selects an input video signal from the video input unit 10 and performs frame interpolation. Send to part 5.

  When the input video signal is not a signal that has been pulled down 2-3, the pull-down inverse conversion unit 2 does not operate, the selector 9 selects the input video signal according to the control of the control unit 6, and the frame interpolation unit 4 performs frame interpolation. I do.

  Next, an example of frame interpolation is shown. FIG. 3A shows a video signal of 24 frames per second. As shown in FIG. 3B, this can be made 120 frames per second by repeating the original frame four times. If interpolation is performed by this method, it is not necessary to create an interpolated frame with reference to a subsequent frame, so that the delay of the display video with respect to the input video can be suppressed.

  As another method, intermediate frames E, F, G, and H may be inserted into frames A and B as shown in FIG. Here, the intermediate frames E, F, G, and H are created from the frames A and B. In this case, although a delay of the display image occurs as compared with the method of FIG. 3A, a smooth image can be obtained.

  In the frame interpolation unit 4, whether the frame interpolation is performed by the method shown in FIG. 3 (2) or the method shown in FIG. 3 (3) can be selected by a user operation input in the operation unit 8. The control unit 6 controls the frame interpolation unit 4 according to the user input information in the operation unit 8 to make the above selection. In this way, the user can select whether to display an image without delay or to display a smooth image.

  When the motion of the video is large, or when the motion vector cannot be detected due to the small motion part (moving image part) in the video, the intermediate frames E, F, G, H should be appropriately created. May cause problems such as a sense of incongruity in the motion of the video and a blurring of the still part of the video. In such a case, the control unit 6 controls the frame interpolation unit 4 by reducing the number of interpolation frames or inputting an instruction to adjust the amount of interpolation to each storage frame in the operation unit 8. It is possible to avoid or mitigate the above-mentioned adverse effects. FIG. 3 (4) shows an example in which the intermediate frame M is inserted after repeating the original frame A three times, and the intermediate frame N is inserted after repeating the original frame B three times. In this way, by repeating the original frame and the intermediate frame to form an interpolated frame and controlling the ratio of the intermediate frame, frame rate conversion can be performed without a sense of incongruity even when a motion vector cannot be detected.

  FIG. 4 (1) shows a video signal of 60 frames per second used for normal television broadcasting. When the video signal itself is selected by the selector 9, the frame interpolation unit 4 repeats the same frame twice, so that a video signal of 120 frames per second shown in FIG. If interpolation is performed by this method, it is not necessary to create an interpolated frame with reference to a subsequent frame, so that the delay of the display video with respect to the input video can be suppressed.

  In this specification, the 2-3 pull-down has been described as an example. However, when a video signal converted from 24 fps to 30 fps by other pull-down processing such as 2-3-3-2 is input, Similar processing is performed.

<Effect>
The image display apparatus of the present invention includes a frame rate determination unit 5 that performs frame rate determination and pull-down detection of an input video signal input from the outside, and the input video signal is 2-3 pull-down from a video signal of 24 frames / second. A pull-down inverse conversion unit 2 for performing a pull-down inverse conversion on the progressive signal and outputting a reverse-conversion video signal of 24 frames / second when the frame rate determination unit determines that the processed progressive signal is an external signal; A selector 9 that selects either the input video signal or the inversely converted video signal according to an operation input, and frame interpolation that improves the frame rate by inserting an interpolated frame between the original frames of the video signal selected by the selector 9 Part 4. As a result, it is possible to select whether to perform normal frame rate conversion or to perform frame rate conversion that preserves the image quality of the movie signal by performing frame rate conversion on the inversely converted video signal according to the user's wishes. I can do it.

  In the image display device of the present invention, the frame interpolation unit 4 creates an interpolation frame by repeating each original frame a predetermined number of times according to an external operation input, or creates an intermediate frame based on the previous and next original frames. Since it is executed by selecting either the interpolation frame or not, depending on the user's preference, select whether to interpolate so that the video is clear with no video blur or to interpolate with some video blurring I can do it.

  Further, in the image display device of the present invention, the frame interpolation unit 4 combines the frame obtained by repeating each original frame a predetermined number of times and the intermediate frame created based on the previous and subsequent original frames to obtain an interpolation frame, and the intermediate frame in the interpolation frame Is controlled according to an external operation input, so that it is possible to perform frame rate conversion without a sense of incongruity even for images in which motion detection is difficult.

  DESCRIPTION OF SYMBOLS 1 Image display apparatus, 2 pulldown reverse conversion part, 3 frame memory, 4 frame interpolation part, 5 frame rate determination part, 6 control part, 7 image display part, 8 operation part, 9 selector, 10 video input part.

Claims (3)

A frame rate determination unit that performs frame rate determination and pull-down detection of an input video signal input from the outside;
When the frame rate determination unit determines that the input video signal is a progressive signal obtained by performing 2-3 pulldown processing from a video signal of 24 frames / second, the progressive signal is subjected to pulldown inverse conversion to be 24 frames. A pull-down inverse conversion unit for outputting an inversely converted video signal per second;
A selector for selecting either the input video signal or the inversely converted video signal according to an external operation input;
A frame interpolation unit that inserts an interpolation frame between original frames of the video signal selected by the selector to improve a frame rate;
Image display device. In response to an external operation input, the frame interpolation unit repeats each of the original frames a predetermined number of times to create the interpolation frame, or creates an intermediate frame based on the previous and subsequent original frames as the interpolation frame, Select and run
The image display device according to claim 1. The frame interpolation unit combines the frame obtained by repeating each of the original frames a predetermined number of times and an intermediate frame created based on the previous and subsequent original frames to form the interpolation frame, and the ratio of the intermediate frame in the interpolation frame is externally operated. Control according to the input,
The image display device according to claim 1.

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