JP4772008B2 - Image display apparatus and method, image processing apparatus and method - Google Patents

Description

  The present invention relates to an image display apparatus and method having a function of converting a frame rate or a field rate, and more specifically, a motion amount between frames or fields resulting from motion compensation type rate conversion processing is a predetermined value. The present invention relates to an image display apparatus that prevents image quality degradation of a moving image including a larger area, an image display method using the apparatus, an image processing apparatus, and an image processing method using the image processing apparatus.

  In contrast to a cathode ray tube (CRT) that has been mainly used for the purpose of embodying moving images, an LCD (Liquid Crystal Display) moves a viewer when a moving image is displayed. There is a so-called motion blur defect in which the outline of a part is blurred and perceived. It has been pointed out that this motion blur is caused by the LCD display method itself (see, for example, Patent Document 1 and Non-Patent Document 1).

  In a CRT that performs display by scanning an electron beam to emit light from a phosphor, the light emission of each pixel is substantially in an impulse shape although there is some afterglow of the phosphor. This is called an impulse type display system. On the other hand, in the LCD, the charge stored by applying an electric field to the liquid crystal is held at a relatively high rate until the next electric field is applied. In particular, in the case of the TFT method, a TFT switch is provided for each dot constituting a pixel, and an auxiliary capacitor is usually provided for each pixel, and the ability to hold stored charges is extremely high. For this reason, light emission continues until the pixel is rewritten by applying an electric field based on image information of the next frame or field (hereinafter referred to as a frame). This is called a hold type display method.

  In the hold-type display method as described above, the impulse response of the image display light has a temporal spread, so that the time frequency characteristic is deteriorated, and the spatial frequency characteristic is accordingly lowered, resulting in motion blur. In other words, since the human line of sight smoothly follows a moving object, if the light emission time is long as in the hold type, the movement of the image becomes jerky due to the time integration effect and looks unnatural.

  In order to improve motion blur in the hold-type display method, a technique for converting a frame rate (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.

  Conventionally, as a method for converting the frame rate, there are various methods such as simply repeatedly reading out the same frame a plurality of times and frame interpolation by linear interpolation between frames (for example, see Non-Patent Document 2). ). However, in the case of frame interpolation processing by linear interpolation, motion unnaturalness (jerkiness, judder) due to frame rate conversion occurs, and motion blur interference due to the hold type display method described above is sufficiently improved. The image quality was insufficient.

  Therefore, in order to eliminate the influence of the jerkiness and improve the moving image quality, motion compensation type frame interpolation (motion compensation) processing using a motion vector has been proposed. According to this motion compensation process, since the moving image itself is captured and compensated, resolution is not deteriorated and jerkiness is not generated, and a very natural moving image can be obtained. Furthermore, since the interpolated image signal is formed by motion compensation, it is possible to sufficiently improve the motion blur interference caused by the hold type display method described above.

  Patent Document 1 described above discloses a technique for improving a decrease in spatial frequency characteristics that causes motion blur by increasing a 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.

  FIG. 29 is a block diagram showing a schematic configuration of an FRC drive display circuit in a conventional liquid crystal display device. In the figure, the FRC drive display circuit interpolates an image signal subjected to motion compensation processing between frames of an input image signal. An FRC unit 100 that converts the number of frames of the input image signal, an active matrix type liquid crystal display panel 103 having a liquid crystal layer and electrodes for applying a scanning signal and a data signal to the liquid crystal layer, and an FRC unit And an electrode driving unit 104 for driving the scanning electrodes and the data electrodes of the liquid crystal display panel 103 based on the image signal whose frame rate is converted by 100.

  The FRC unit 100 includes a motion vector detection unit 101 that detects motion vector information from an input image signal, an interpolation frame generation unit 102 that generates an interpolation frame based on the motion vector information obtained by the motion vector detection unit 101, and Is provided.

  In the above configuration, the motion vector detection unit 101 may obtain the motion vector information using, for example, a block matching method or a gradient method described later, or the motion vector information is included in some form in the input image signal. If this is the case, this may be used. For example, image data compression-encoded using the MPEG method includes motion vector information of a moving image calculated at the time of encoding, and the motion vector information may be acquired.

  FIG. 30 is a diagram for explaining frame rate conversion processing by the conventional FRC drive display circuit shown in FIG. The FRC unit 100 generates an interpolated frame (an image colored in gray in the figure) by motion compensation using the motion vector information output from the motion vector detecting unit 101, and the generated interpolation By sequentially outputting the frame signal together with the input frame signal, processing for converting the frame rate of the input image signal from, for example, 60 frames per second (60 Hz) to 120 frames per second (120 Hz) is performed.

  FIG. 31 is a diagram for explaining an interpolation frame generation process performed by the motion vector detection unit 101 and the interpolation frame generation unit 102. The motion vector detection unit 101 detects the motion vector 105 from the frame # 1 and the frame # 2 shown in FIG. That is, the motion vector detection unit 101 obtains the motion vector 105 by measuring how much and in which direction the frame # 1 and frame # 2 have moved in 1/60 second. Next, the interpolation frame generation unit 102 allocates the interpolation vector 106 between the frame # 1 and the frame # 2 using the obtained motion vector 105. An interpolation frame 107 is generated by moving the object (in this case, an automobile) from the position of frame # 1 to a position after 1/120 second based on the interpolation vector 106.

  In this way, motion compensation frame interpolation processing is performed using motion vector information, and the display frame frequency is increased to change the display state of the LCD (hold type display method) to the display state of the CRT (impulse type display method). It is possible to improve the image quality degradation due to motion blur that occurs when displaying a moving image.

  Here, in the motion compensation frame interpolation process, detection of a motion vector is indispensable for motion compensation. As typical techniques for this motion vector detection, for example, a block matching method, a gradient method, and the like have been proposed. In these methods, a motion vector is detected for each pixel or small block between two consecutive frames, and each pixel or each small block of the interpolation frame between the two frames is interpolated using this motion vector. To do. That is, the number of frames is converted by correctly correcting and interpolating an image at an arbitrary position between two frames.

  By the way, since a moving image has a high correlation between frames and has continuity in the time axis direction, a moving pixel or block in a certain frame is the same in a subsequent frame or a preceding frame. It is often moving with the amount of movement. For example, in the case of a moving image in which the ball rolls from right to left on the screen, the ball area moves with the same amount of movement in any frame. That is, there are many cases where motion vectors have continuity between consecutive frames.

  Thus, by referring to the motion vector detection result in the previous frame, the motion vector in the next frame can be detected more easily or more accurately. For example, in the iterative gradient method improved from the gradient method, the motion vector of the neighboring block already detected in the previous frame or the current frame is used as the initial displacement vector for the detected block, and this is used as the starting point for the gradient method. A method of repeating the calculation is used. According to this method, it is possible to obtain an almost accurate motion amount by repeating the gradient method about twice.

  That is, in this iterative gradient method, as shown in FIG. 32 (A), the motion vectors of the neighboring blocks that have already been detected are obtained from the initial displacement vector 110 and the first gradient method for the detected block. The sum of the first motion vector 111 and the second motion vector 112 obtained by the second gradient method is the motion vector 113 that is finally output.

  By the way, when FRC is realized by real-time processing by hardware, simulation processing by computer, etc., it is realistic due to restrictions such as hardware circuit configuration, memory area restrictions, and computer processing speed. It is necessary to limit the calculation range when evaluating motion vectors.

  For example, the interpolation vector evaluation unit provided in the interpolation frame generation unit 102 described above determines the accuracy of the motion vector obtained by the gradient method calculation from the image information of the detection block and the detection block. A difference value (referred to as DFD (Displaced Field Difference)) from the image information of the previous block pointed to by the motion vector is calculated and evaluated, but the image information is also secured in the evaluation area at this time It is necessary to limit the range of vector evaluation calculation due to area restrictions.

  Note that the DFD is an index indicating the degree of accuracy of the candidate vector. The smaller the DFD value, the better the matching between the detected block and the previous block indicated by the motion vector from the detected block, and the corresponding candidate. Indicates that the vector is more appropriate.

  However, in the gradient method described above, when the amount of motion between frames is large, the vector obtained by the gradient method calculation may exceed the limited vector evaluation calculation range. That is, in the gradient method calculation, a vector is obtained by mathematical calculation based on the difference in gradient of the image information of the previous and subsequent frames, and thus a vector exceeding the limited vector evaluation calculation range may be calculated.

  As described above, when a vector exceeding the vector evaluation calculation range is calculated at the time of motion vector detection, the output stage of the motion vector detection unit is used due to memory restrictions of image information at the time of subsequent interpolation vector evaluation. It is necessary to limit the motion vector.

  For example, FIGS. 32B and 32C show a case where the second motion vector 112 obtained by the second gradient method exceeds the vector evaluation calculation range. In such a case, there are various methods for determining the motion vector to be finally output.

  For example, as shown in FIG. 32B, for example, a vector obtained from the sum of the initial displacement vector 110, the first motion vector 111, and the second motion vector 112 is within a vector evaluation calculation range. A vector clipped at the maximum value is output as the final motion vector 113.

  As another method, as shown in FIG. 32 (c), since the second motion vector 112 exceeds the vector evaluation calculation range, the first motion vector 111 and the initial displacement vector 110 are summed as effective vectors. Is output as the final motion vector 113.

  In this way, when the vector obtained by gradient method calculation exceeds the vector evaluation calculation range, special processing is performed and some vector is output, but this output vector is calculated by gradient method etc. The result is not a faithful reflection and is not an accurate motion vector. For this reason, when a motion compensation frame interpolation process is performed using a motion vector that has been subjected to such special processing, the interpolated image may fail.

  Further, even if the vector evaluation calculation range is set sufficiently wide, the special processing as described above is not necessary, but the same pattern as the detected block ( Image information) is likely to exist in a plurality of other blocks within the screen or calculation range, and motion vector candidates increase, making it difficult to detect an accurate motion vector.

In addition to the iterative gradient method as a motion vector detection method, for example, when using a block matching method, it is necessary to limit the vector search range, etc. It is difficult to output an accurate motion vector.
Japanese Patent No. 3295437 Shuichi Ishiguro, Taiichi Kurita, “Examination of video quality of hold light emission display by 8 × CRT”, IEICE Technical Report, The Institute of Electronics, Information and Communication Engineers, EID96-4 (1996-06), p. 19-26 Tatsuro Yamauchi, “Television Conversion”, Television Society Journal, Vol. 45, no. 12, pp. 1534-1543 (1991)

  By the way, as a source of a video signal, there is a video shot with a normal television video camera. Among these images, for example, images shot by panning the shooting camera at high speed, and images of cars and trains traversing the screen at high speed, etc. Moving) may be included.

  In such a moving image, since the amount of motion between frames is excessive, it is difficult to output an accurate motion vector. That is, in FRC, it is more difficult to generate an interpolated image more accurately for an object with a larger amount of motion.

  Here, if there is a moving object in the screen, humans gaze at this moving object and follow it with their eyes, so if there is an error in detecting the motion vector of FRC and a broken video appears in the moving object, the image quality is particularly high. It can be said that the deterioration is easily noticeable.

  However, normally, a subject photographed by a camera includes blur (camera blur) due to the light accumulation time of the camera when the amount of movement is large. As described above, since the motion blur caused by the hold-type display method is less noticeable for the image originally including the blur, the image quality improvement effect by the FRC is small.

  Therefore, if FRC is performed, if there is a possibility that an error occurs in motion vector detection due to a large amount of motion between frames and the interpolation image may be destroyed, the motion vector It is better not to perform motion compensation frame interpolation processing using.

  Further, as another video signal source, there is a video by computer graphic (CG). In some cases, these videos include a video that scrolls at high speed and objects (including characters) that move at high speed. In this CG video, since there is no camera blur that occurs during the above-described camera shooting, when FRC is performed, an image quality improvement effect can be obtained more effectively than the camera shooting video.

  However, in such a CG video, when a motion vector detection error occurs due to a large amount of motion between frames and the interpolated image breaks down, it is particularly in comparison with a camera-captured video. Deterioration in image quality is more noticeable. Therefore, when such image quality degradation is particularly noticeable, it is better not to perform motion compensation frame interpolation processing using motion vectors.

  The present invention has been made in view of the above problems, and prevents image quality deterioration of a moving image in which the amount of motion between frames or between fields is larger than a predetermined value due to motion compensation type frame rate conversion (FRC) processing. An object of the present invention is to provide an image display device and method, and an image processing device and method that can be used.

According to a first aspect of the present application, an image signal generated by performing a motion compensation process on the input image signal based on motion vector information detected in a predetermined block unit between frames or fields of the input image signal, by weighted addition of an image signal generated without applying the motion compensation process on an input image signal in a predetermined ratio, and interpolation image generating portion in which generates an interpolation image signal, between frames of the input image signal or An image display device comprising rate conversion means having an image interpolation unit for converting the number of frames or the number of fields of the input image signal by interpolating the interpolated image signal between fields. The display device is configured to display the input image signal based on the number of blocks in one frame or one field in which the motion vector information exceeds a predetermined range. A determination unit configured to determine, for each frame or field, whether or not a motion amount between frames or between fields is greater than a predetermined value; and the interpolated image generation unit includes a frame or a field of the input image signal by the determination unit. When it is determined that the amount of motion in between is larger than a predetermined value, the addition ratio of the image signal generated by applying motion compensation processing to the input image signal for the region including all the pixels in the frame or field is The weighted addition ratio is changed so as to be low.

According to a second aspect of the present invention, the interpolated image generating unit generates an image generated by subjecting the input image signal to motion compensation processing when the amount of motion between frames or fields of the input image signal is greater than a predetermined value. the ratio of the signal to 0, when the motion amount between frames or between fields of the input image signal is smaller than a predetermined value, the ratio of the image signal generated without applying motion compensation processing on the input image signal and 0 It is characterized by that.

According to a third invention of the present application, the interpolated image generation unit uses an image signal that has been subjected to linear interpolation processing between frames or fields of the input image signal as an image signal that is not subjected to the motion compensation processing. Features.

According to a fourth aspect of the present application, the determination means prevents the current frame from being frequently switched between a frame or field determined to have a large amount of motion and a frame or field determined to have a small amount of motion. Alternatively, a predetermined value for determining whether or not a motion amount between frames or fields of the input image signal with respect to a field is larger than a predetermined value is changed according to a determination result of the motion amount with respect to the previous frame or field. To do.

In a fifth aspect of the present application, when the determination unit determines that the amount of motion between frames or fields of the input image signal is greater than a predetermined value , the determination result is continued for a period of several frames thereafter. It is characterized by outputting .

According to a sixth aspect of the present application, an image signal generated by performing a motion compensation process on the input image signal based on motion vector information detected in a predetermined block unit between frames or fields of the input image signal, by weighted addition of an image signal generated without applying motion compensation processing at a predetermined ratio to an input image signal, and the interpolation image generating step among which generates an interpolation image signal, between frames of the input image signal or An image display method comprising a rate conversion step including an image interpolation step of converting the number of frames or the number of fields of the input image signal by interpolating the interpolated image signal between fields. Based on the number of blocks in one frame or one field in which vector information exceeds a predetermined range, there is an interval between the frames of the input image signal. Includes a step of determining, for each frame or field, whether or not the amount of motion between fields is greater than a predetermined value, and the interpolated image generation step includes a step of determining the amount of motion between frames or fields of the input image signal. If determined to be larger, the weighting is performed so that an addition ratio of an image signal generated by performing motion compensation processing on the input image signal is low for a region including all pixels in the frame or field. The addition ratio is changed.

According to a seventh aspect of the present application, an image signal generated by subjecting the input image signal to motion compensation processing based on motion vector information detected in units of a predetermined block between frames or fields of the input image signal, by weighted addition of an image signal generated without applying the motion compensation process on an input image signal in a predetermined ratio, and interpolation image generating portion in which generates an interpolation image signal, between frames of the input image signal or An image processing apparatus comprising rate conversion means having an image interpolation unit that converts the number of frames or the number of fields of the input image signal by interpolating the interpolated image signal between fields. The inset image generation unit is configured to input the input image signal based on the number of blocks in one frame or one field in which the motion vector information exceeds a predetermined range. It is determined that the amount of motion between frames or fields of the input image signal is greater than a predetermined value by the determination means for determining whether the amount of motion between frames or fields is greater than a predetermined value for each frame or field In this case, the weighted addition ratio is changed so that the addition ratio of the image signal generated by performing motion compensation processing on the input image signal is low for an area including all the pixels in the frame or field. It is characterized by.

According to an eighth aspect of the present application, an image signal generated by performing a motion compensation process on the input image signal based on motion vector information detected in units of predetermined blocks between frames or fields of the input image signal, by weighted addition of an image signal generated without applying motion compensation processing at a predetermined ratio to an input image signal, and the interpolation image generating step among which generates an interpolation image signal, between frames of the input image signal or An image processing method comprising a rate conversion step including an image interpolation step of converting the number of frames or the number of fields of the input image signal by interpolating the interpolated image signal between fields, Based on the number of blocks in one frame or one field in which vector information exceeds a predetermined range, there is an interval between the frames of the input image signal. Includes a step of determining, for each frame or field, whether or not the amount of motion between fields is greater than a predetermined value, and the interpolated image generation step includes a step of determining the amount of motion between frames or fields of the input image signal. If determined to be larger, the weighting is performed so that an addition ratio of an image signal generated by performing motion compensation processing on the input image signal is low for a region including all pixels in the frame or field. The addition ratio is changed.

  According to the present invention, when an image signal having a motion amount between frames or fields larger than a predetermined value is input, the image quality of the display image is effectively prevented by reducing the compensation intensity of the motion compensation process. can do.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of an image display device of the present invention will be described in detail with reference to the accompanying drawings. 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 showing a configuration example of a motion compensated frame rate conversion unit provided in the image display apparatus of the present invention. In the figure, 10 is a frame rate conversion unit (hereinafter referred to as FRC unit), and the FRC unit 10 is The vector detection unit 11 corresponds to the rate conversion means of the present invention and detects a motion vector between two consecutive frames included in the input image signal, and an interpolation frame (interpolated image) based on the detected motion vector And a frame generation unit 12 for generating. 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.

  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 detecting the motion, 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.

  The FRC unit 10 corresponds to the rate conversion means of the present invention, the motion vector detection unit 11e corresponds to the motion vector detection unit of the present invention, and the interpolation vector evaluation unit 11f is the interpolation vector allocation of the present invention. It corresponds to the part.

  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 evaluates the motion vector detected by the motion vector detection unit 11e, assigns an optimal interpolation vector to the inter-frame interpolation block based on the evaluation result, and sends the interpolated block to the frame generation unit 12. Output.

  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 And a time base conversion unit 12d that generates an output image signal (RGB signal) by inserting 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). By outputting this to the display panel, It is possible to improve motion picture quality by reducing motion blur. 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 (2 times) is described, but for example, 90 frames / second (1.5 times), Needless to say, the present invention may be applied when an output image signal of 180 frames / second (three times) is obtained.

  The image display apparatus of the present invention includes the FRC unit 10 shown in FIG. 1, and when the amount of motion between frames of the input image signal is large, using means such as invalidating motion compensation processing in the FRC unit 10, The main purpose is to prevent image quality degradation caused by FRC processing. The present invention can be applied to all image display devices having hold-type display characteristics such as a liquid crystal display, an organic EL display, and an electrophoretic display. In the following embodiments, a liquid crystal display panel is used as a display panel. A case where the present invention is applied to a liquid crystal display device using the above will be described as a representative example.

(First embodiment)
The first embodiment of the present invention forces the output of the motion vector detection unit 11e to invalidate the motion compensation processing of the FRC unit 10 when the motion amount between frames of the input image signal is larger than a predetermined value. Thus, it is a zero vector.

  FIG. 3 is a block diagram illustrating an exemplary configuration of a main part of the liquid crystal display device according to the first embodiment of the present invention. The liquid crystal display device includes an FRC unit 10, a motion amount determination unit 14, a control unit 15, and a switching unit 16. The electrode driving unit 18 and the liquid crystal display panel 19 are provided. The switching unit 16 is provided between the motion vector detection unit 11e and the interpolation vector evaluation unit 11f in the FRC unit 10 and transfers the motion vector from the motion vector detection unit 11e to the 0 vector 17 in accordance with an instruction from the control unit 15. Switch.

  The motion vector detection unit 11e outputs a motion vector detected by a predetermined calculation, and the vector calculated during the motion vector detection calculation exceeds the predetermined vector evaluation calculation range set in the interpolation vector evaluation unit 11f. For this reason, the OB flag “1” is output to the block that has been subjected to some special processing described above with reference to FIGS. It should be noted that an OB flag “0” is output to a block for which a vector exceeding a predetermined vector evaluation calculation range is not calculated during the motion vector detection calculation and no special processing is performed.

  The motion amount determination unit 14 counts the number of OB flags “1”, which means that the predetermined vector evaluation calculation range has been exceeded during the motion vector detection calculation by the motion vector detection unit 11e, and this count value for each frame. Is determined to be greater than a predetermined threshold, thereby determining whether the amount of motion between frames of the input image signal is greater than a predetermined value.

  As described above, the motion amount determination unit 14 of the present embodiment compares the number of blocks in one screen where the motion vector calculated by the motion vector detection unit 11e exceeds the predetermined vector calculation evaluation range with a predetermined value. Although it is determined whether or not the amount of motion between frames of the input image signal exceeds a predetermined range, it goes without saying that the present invention is not limited to the above configuration.

  And the control part 15 is provided with CPU for controlling each said part, and when the motion amount determination part 14 determines with an input image signal being an image signal which has a motion amount larger than a predetermined value, in the FRC part 10 Control to invalidate the motion compensation process. That is, the liquid crystal display device of this embodiment determines whether or not the amount of motion between frames of the input image signal is larger than a predetermined value, and controls the motion compensation processing of the FRC unit 10 according to the determination result. It is.

  The liquid crystal display panel 19 is an active matrix liquid crystal display having a liquid crystal layer and electrodes for applying scanning signals and data signals to the liquid crystal layer. The electrode drive unit 18 is a display driver for driving the scan electrodes and data electrodes of the liquid crystal display panel 19 based on the image signal whose frame rate is converted by the FRC unit 10.

  The drive frequency of the liquid crystal display panel 19 is the frame frequency converted by the FRC unit 10. Therefore, when an image signal input at a frame frequency of 60 Hz is converted to a frame frequency of 120 Hz by the FRC unit 10, the drive frequency of the liquid crystal display panel 19 is 120Hz. However, when frame frequency conversion by FRC processing is not performed and the input image signal is displayed and output as it is, the drive frequency of the liquid crystal display panel 19 becomes the frame frequency of the input image signal.

  When the motion amount determination unit 14 determines that the amount of motion between the frames of the input image signal is larger than the predetermined value, the control unit 15 switches the switching unit 16 to the 0 vector 17 side, and the motion vector detection unit 11e performs the calculation. Forced motion vector is replaced with 0 vector.

  When the motion amount determination unit 14 determines that the amount of motion between frames of the input image signal is an image signal smaller than a predetermined value, the switching unit 16 is switched to the motion vector detection unit 11e side, and the motion vector detection unit The motion vector detected in 11e is input to the interpolation vector evaluation unit 11f.

  As described above, during normal moving image display, the motion compensation type FRC process can improve the moving image quality, and when an image signal having a motion amount between frames larger than a predetermined value is input, By disabling the motion compensation processing by setting the vector to 0 vector, the motion vector detection error due to the large amount of motion between frames, the motion compensation error, etc. are eliminated, and the image quality degradation caused by the motion compensation type FRC processing is eliminated. Can be effectively prevented.

(Second Embodiment)
In the second embodiment of the present invention, when the amount of motion between frames of the input image signal is larger than a predetermined value, the interpolation from the interpolation vector evaluation unit 11f is performed in order to invalidate the motion compensation processing of the FRC unit 10. The interpolation vector is set to 0 vector so that interpolation between pixels at different positions does not occur.

  FIG. 4 is a block diagram illustrating an exemplary configuration of a main part of a liquid crystal display device according to the second embodiment of the present invention. The liquid crystal display device includes an FRC unit 10, a motion amount determination unit 14, a control unit 15, and a switching unit 16. The electrode driving unit 18 and the liquid crystal display panel 19 are provided. The switching unit 16 is provided between the interpolation vector evaluation unit 11f and the interpolation frame generation unit 12b in the FRC unit 10, and sets the interpolation vector from the interpolation vector evaluation unit 11f to 0 according to an instruction from the control unit 15. Switch to vector 17.

  The motion vector detection unit 11e outputs a motion vector detected by a predetermined calculation to the interpolation vector evaluation unit 11f, and a vector calculated during the motion vector detection calculation is set in the interpolation vector evaluation unit 11f. OB flag information indicating whether or not the vector evaluation calculation range is exceeded is output to the motion amount determination unit 14 for each block.

  The motion amount determination unit 14 determines whether or not the motion amount between frames of the input image signal is larger than a predetermined value based on the OB flag information output from the motion vector detection unit 11e, and the determination result is determined by the control unit. 15 is output.

  When the motion amount determination unit 14 determines that the motion amount between frames of the input image signal is larger than the predetermined value, the control unit 15 switches the switching unit 16 to the 0 vector 17 side, and the interpolation vector evaluation unit 11f The allocated interpolation vector is set to 0 vector. When the motion amount determination unit 14 determines that the motion amount between frames of the input image signal is smaller than the predetermined value, the switching unit 16 is switched to the interpolation vector evaluation unit 11f side, and the interpolation vector evaluation unit 11f The allocated interpolation vector is input to the interpolation frame generation unit 12b.

  As described above, during normal moving image display, the motion compensation type FRC processing can improve the moving image quality, and if an image signal having a motion amount between frames larger than a predetermined value is input, By effectively setting the interpolation vector to 0 vector and invalidating the motion compensation process, the motion vector detection error, the motion compensation error, etc. due to the large amount of motion between frames are obtained as in the first embodiment. Therefore, it is possible to effectively prevent the image quality deterioration caused by the motion compensation type FRC processing.

(Third embodiment)
In the third embodiment of the present invention, when the amount of motion between frames of the input image signal is larger than a predetermined value, the interpolation from the interpolation vector evaluation unit 11f is performed in order to invalidate the motion compensation processing of the FRC unit 10. The interpolation vector is set to 0 vector so that interpolation between pixels at different positions does not occur.

  FIG. 5 is a block diagram illustrating an exemplary configuration of a main part of a liquid crystal display device according to the third embodiment of the present invention. The liquid crystal display device includes an FRC unit 10, a motion amount determination unit 14, a control unit 15, and a switching unit 16. The electrode driving unit 18 and the liquid crystal display panel 19 are provided. The switching unit 16 is provided between the interpolation vector evaluation unit 11f and the interpolation frame generation unit 12b in the FRC unit 10, and sets the interpolation vector from the interpolation vector evaluation unit 11f to 0 according to an instruction from the control unit 15. Switch to vector 17.

  The motion vector detection unit 11e determines whether the motion vector detected by the predetermined calculation and the vector calculated during the motion vector detection calculation exceed the predetermined vector evaluation calculation range set in the interpolation vector evaluation unit 11f. Is output to the interpolation vector evaluation unit 11f.

  The interpolation vector evaluation unit 11f evaluates the motion vector output by the motion vector detection unit 11e, and assigns an optimal interpolation vector for each interpolation block. Specifically, an equivalent motion vector is assigned to the interpolation block to which the motion vector points from the detected block. However, the allocated interpolation block may be indicated by a detection block different from the detected block. That is, a plurality of motion vectors may be assigned to one interpolation block. In such a case, DFD is calculated for each of a plurality of motion vectors, and a motion vector having the smallest DFD (that is, more correct) is adopted and assigned.

  At this time, OB flag information corresponding to the allocated motion vector is also allocated for each interpolation block. Then, the OB flag information for each interpolation block is output to the motion amount determination unit 14.

  The motion amount determination unit 14 uses the OB flag information provided for each interpolation block output from the interpolation vector evaluation unit 11f, so that the motion amount between frames of the input image signal is larger than a predetermined vector evaluation calculation range. It is determined whether or not. That is, when the assigned motion vector is detected and calculated, the number of OB flags “1”, which means that the predetermined vector evaluation calculation range is exceeded, is counted, and this count value is larger than a predetermined threshold value for each frame. It is determined whether or not the amount of motion between frames of the input image signal is greater than a predetermined value.

  When the motion amount determination unit 14 determines that the motion amount between frames in the input image signal is larger than the predetermined value, the control unit 15 switches the switching unit 16 to the 0 vector 17 side, and the interpolation vector evaluation unit 11f The allocated interpolation vector is set to 0 vector. When the motion amount determination unit 14 determines that the motion amount between frames of the input image signal is smaller than the predetermined value, the switching unit 16 is switched to the interpolation vector evaluation unit 11f side, and the interpolation vector evaluation unit 11f The allocated interpolation vector is input to the interpolation frame generation unit 12b.

  As described above, during normal moving image display, the motion compensation type FRC processing can improve the moving image quality, and if an image signal having a motion amount between frames larger than a predetermined value is input, By effectively setting the interpolation vector to 0 vector and invalidating the motion compensation process, the motion vector detection error, the motion compensation error, etc. due to the large amount of motion between frames are obtained as in the first embodiment. Therefore, it is possible to effectively prevent the image quality deterioration caused by the motion compensation type FRC processing.

(Fourth embodiment)
In the fourth embodiment of the present invention, a path for bypassing the FRC unit 10 is provided, and when the amount of motion between frames of the input image signal is larger than a predetermined value, the input image signal is input to the bypass path side. The drive frequency of the liquid crystal display panel 19 is changed in accordance with the frame frequency of the input image signal. That is, when an image signal having a motion amount between frames larger than a predetermined value is input, the frame rate conversion is not performed and the input image signal is switched to be displayed and output on the liquid crystal display panel 19 as it is.

  FIG. 6 is a block diagram illustrating an exemplary configuration of a main part of a liquid crystal display device according to the fourth embodiment of the present invention. The liquid crystal display device includes an FRC unit 10, a decoding unit 21, a motion amount determination unit 14, and a control unit 15. , The switching unit 16, the electrode driving unit 18, the liquid crystal display panel 19, and a path 20 for bypassing the FRC unit 10. The switching unit 16 is provided in the preceding stage of the FRC unit 10 and switches whether to input an input image signal to the FRC unit 10 or to the route 20 in accordance with an instruction from the control unit 15.

  Here, when the input image signal is a compressed input signal (for example, MPEG, DivX, etc.) compressed using motion vector information or the like, the compressed input signal is restored to the image signal by the decoding unit 21 and FRC is used. Input to the unit 10. At this time, when the input image signal is compressed using the motion vector information, the motion vector used for the restoration can be extracted from the decoding unit 21. In the present embodiment, based on the extracted motion vector, the motion amount determination unit 14 determines whether or not the motion amount between frames of the input image signal is larger than a predetermined value.

  Specifically, when the total value or average value for one frame of the length of the motion vector output from the decoding unit 21 is larger than a predetermined threshold, or the length of the motion vector output from the decoding unit 21 is predetermined. If the count value is greater than a predetermined value, the amount of motion between frames is determined to be an image signal greater than the predetermined value.

  Here, the motion amount extracted between the frames of the input image signal is determined using the motion vector extracted by the decoding unit 21. Of course, the motion amount determination as described above in the first to third embodiments is performed. Needless to say, the processing may be employed, but the present invention is not limited thereto.

  When the motion amount determination unit 14 determines that the amount of motion between frames of the input image signal is greater than a predetermined value, the control unit 15 switches the switching unit 16 to the path 20 side to bypass the FRC unit 10. Also, when the motion amount determination unit 14 determines that the motion amount between frames of the input image signal is smaller than a predetermined value, the switching unit 16 is switched to the FRC unit 10 side to perform FRC processing (motion Compensation frame interpolation process). Note that the switching unit 16 may be provided at the subsequent stage of the FRC unit 10 so that the output signal of the FRC unit 10 and the output signal of the path 20 are switched and output to the liquid crystal panel 19.

  Further, in the present embodiment, the control unit 15 can change the drive frequency of the liquid crystal display panel 19, and when an image signal whose amount of motion between frames is larger than a predetermined value is input, the input image signal is sent to the path 20 side. The drive frequency of the liquid crystal display panel 19 is changed in accordance with the frame frequency of the input image signal.

  FIG. 7 is a diagram showing the relationship between input data and output data according to the fourth embodiment of the present invention. FIG. 7A shows input data to the path 20, and FIG. 7B shows output data from the path 20. As shown in FIG. 7A, when an input image signal (input data) is input to the path 20 at a frame frequency of 60 Hz, the display time per frame is about 16.7 ms. The control unit 15 controls the electrode drive unit 18 which is a display driver to change the drive frequency of the liquid crystal display panel 19 from 120 Hz to 60 Hz, and the input data is changed to 60 Hz as shown in FIG. The signal is output from the path 20 without converting the frame rate.

  Since the liquid crystal display panel 19 displays a frame output from the path 20 without being converted in the number of frames at a driving frequency of 60 Hz, the display time per frame at this time remains approximately 16.7 ms.

  As described above, during normal moving image display, the motion compensation type FRC process can improve the moving image quality, and when an image signal having a motion amount between frames larger than a predetermined value is input, By bypassing the processing and prohibiting frame rate conversion itself, motion vector detection errors due to large amount of motion between frames, motion compensation errors, etc. are eliminated, and image quality degradation caused by motion compensation type FRC processing Can be effectively prevented.

(Fifth embodiment)
In the fifth embodiment of the present invention, a path for bypassing the FRC unit 10 is provided, and when the amount of motion between frames of the input image signal is larger than a predetermined value, the input image signal is input to the bypass path side. Thus, the input image signal is stored in a memory on the path, and the image signal of the same frame is repeatedly read out from the memory a plurality of times at a high speed to convert the frame rate. That is, when an image signal having a motion amount between frames larger than a predetermined value is input, the frame rate conversion is performed by continuously outputting the input image signal at a high speed without performing the motion compensation type frame rate conversion. The display is switched so as to be output to the display panel 19.

  FIG. 8 is a block diagram showing a configuration example of a main part of a liquid crystal display device according to the fifth embodiment of the present invention. The liquid crystal display device includes an FRC unit 10, a decoding unit 21, a motion amount determination unit 14, and a control unit 15. , The switching unit 16, the electrode driving unit 18, the liquid crystal display panel 19, a path 20 for bypassing the FRC unit 10, and a memory 22 on the path 20. The switching unit 16 is provided in the preceding stage of the FRC unit 10 and switches whether to input an input image signal to the FRC unit 10 or to the route 20 in accordance with an instruction from the control unit 15.

  The motion amount determination unit 14 uses the motion vector information output from the decoding unit 21 to determine whether the motion amount between frames of the input image signal is greater than a predetermined value.

  When the motion amount determination unit 14 determines that the amount of motion between frames of the input image signal is greater than the predetermined value, the control unit 15 switches the switching unit 16 to the path 20 side to bypass the processing of the FRC unit 10. The input image signal is stored in the memory 22. Thereafter, the same frame is repeatedly read out from the memory 22 a plurality of times and a frame insertion process is performed.

  Also, when the motion amount determination unit 14 determines that the motion amount between frames of the input image signal is smaller than a predetermined value, the switching unit 16 is switched to the FRC unit 10 side to perform FRC processing (motion Compensation frame interpolation process). Note that the switching unit 16 may be provided at the subsequent stage of the FRC unit 10 so that the output signal of the FRC unit 10 and the output signal of the memory 22 are switched and output to the liquid crystal panel 19.

  In the present embodiment, the drive frequency of the liquid crystal display panel 19 is not changed and remains 120 Hz. When an image signal with a motion amount between frames larger than a predetermined value is input, the control unit 15 and the memory 22 insert the image signal of the previous or subsequent frame between the frames of the input image signal, thereby inputting the input image signal. A means for converting the number of frames of the image signal is configured. That is, the frame rate (number of frames) of the display image signal input to the electrode driving unit 18 is always the same.

  FIG. 9 is a diagram showing the relationship between input data and output data according to the fifth embodiment of the present invention. FIG. 9A shows input data to the path 20, and FIG. 9B shows output data from the path 20. As shown in FIG. 9A, when an input image signal (input data) is input to the path 20 at a frame frequency of 60 Hz, the display time per frame is about 16.7 ms. The input data is temporarily stored in the memory 22, and as shown in FIG. 9B, an image signal (frame A in the figure) of the frame repeatedly read from the memory 22 at a double speed is output.

  The liquid crystal display panel 19 displays the output data with the image signal of the same frame inserted at a driving frequency of 120 Hz. Since the number of frames is converted by repeatedly reading the same frame twice, the display time per frame at this time is about 8.3 ms.

  As described above, during normal moving image display, the motion compensation type FRC process can improve the moving image quality, and when an image signal having a motion amount between frames larger than a predetermined value is input, By not performing interpolation processing by motion compensation on the image signal, motion vector detection errors due to large amount of motion between frames, motion compensation errors, etc. are eliminated, and motion compensation type FRC processing is performed. The resulting image quality degradation can be effectively prevented. Further, in this case, since the same frame is repeatedly read and the frame rate is converted, it is not necessary to change the driving frequency of the liquid crystal display panel 19.

(Sixth embodiment)
In the sixth embodiment of the present invention, a path for bypassing the FRC unit 10 is provided, and when the amount of motion between frames of the input image signal is larger than a predetermined value, the input image signal is input to the bypass path side. Thus, the input image signal is input to a linear interpolation processing unit on the path, and the image signal subjected to linear interpolation is interpolated. That is, when an image signal having a motion amount between frames larger than a predetermined value is input, switching is performed so as to perform frame rate conversion by performing linear interpolation processing instead of performing interpolation processing by motion compensation. Is.

  FIG. 10 is a block diagram illustrating a configuration example of a main part of a liquid crystal display device according to the fifth embodiment of the present invention. The liquid crystal display device includes an FRC unit 10, a decoding unit 21, a motion amount determination unit 14, and a control unit 15. , The switching unit 16, the electrode driving unit 18, the liquid crystal display panel 19, a path 20 for bypassing the FRC unit 10, and a linear interpolation interpolation processing unit 23 on the path 20. The switching unit 16 is provided in the preceding stage of the FRC unit 10 and switches whether to input an input image signal to the FRC unit 10 or to the route 20 in accordance with an instruction from the control unit 15.

  The motion amount determination unit 14 uses the motion vector information output from the decoding unit 21 to determine whether or not the motion amount between frames of the input image signal is an image signal larger than a predetermined value.

  When the motion amount determination unit 14 determines that the motion amount between frames of the input image signal is larger than the predetermined value, the control unit 15 switches the switching unit 16 to the path 20 side to bypass the FRC unit 10 and input The image signal is input to the linear interpolation processing unit 23. The linear interpolation processing unit 23 inserts an interpolation frame that has been subjected to linear interpolation processing between frames.

  Also, when the motion amount determination unit 14 determines that the motion amount between frames of the input image signal is smaller than a predetermined value, the switching unit 16 is switched to the FRC unit 10 side to perform FRC processing (motion Compensation frame interpolation process). Note that the switching unit 16 may be provided after the FRC unit 10 so that the output signal of the FRC unit 10 and the output signal of the linear interpolation processing unit 23 are switched and output to the liquid crystal panel 19.

  In the present embodiment, the drive frequency of the liquid crystal display panel 19 is not changed and remains 120 Hz. That is, the frame rate (number of frames) of the display image signal input to the electrode driving unit 18 is always the same. When an image signal with a motion amount between frames larger than a predetermined value is input, the linear interpolation processing unit 23 interpolates an image signal subjected to linear interpolation processing between frames of the input image signal, A means for converting the number of frames of the input image signal is configured. The linear interpolation process is to obtain an interpolation frame by linear interpolation using the frame interpolation ratio α from the signal of the previous frame and the signal of the current frame, as described in Non-Patent Document 2 described above. is there.

  FIG. 11 is a diagram showing the relationship between input data and output data according to the fifth embodiment of the present invention. FIG. 11A shows input data to the path 20, and FIG. 11B shows output data from the path 20. As shown in FIG. 11A, when an input image signal (input data) is input to the path 20 at a frame frequency of 60 Hz, the display time per frame is about 16.7 ms. The input data is input to the linear interpolation processing unit 23, and as shown in FIG. 11B, an image signal (in the figure) that has undergone linear interpolation between frames (here, between frames A and B). , Frame A + B) is interpolated and output.

  The liquid crystal display panel 19 displays the output data in which the image signal subjected to the linear interpolation process is interpolated at a driving frequency of 120 Hz. Since the number of frames is converted by interpolation of the image signal subjected to linear interpolation processing, the display time per frame at this time is about 8.3 ms.

  As described above, during normal moving image display, the motion compensation type FRC process can improve the moving image quality, and when an image signal having a motion amount between frames larger than a predetermined value is input, By not performing interpolation processing by motion compensation on the image signal, motion vector detection errors due to large amount of motion between frames, motion compensation errors, etc. are eliminated, and motion compensation type FRC processing is performed. The resulting image quality degradation can be effectively prevented. Further, in this case, since the image signal subjected to the linear interpolation process is interpolated and the frame rate is converted, it is not necessary to change the driving frequency of the liquid crystal display panel 19.

(Seventh embodiment)
In the seventh embodiment of the present invention, a path for bypassing the FRC unit 10 is provided, and when the amount of motion between frames of the input image signal is larger than a predetermined value, the input image signal is input to the bypass path side. The input image signal is input to a black level signal insertion processing unit on the path, and a predetermined monochrome image signal such as a black level signal is inserted. In other words, when an image signal having a motion amount between frames larger than a predetermined value is input, switching to frame rate conversion is performed by performing monochrome image insertion processing instead of interpolation processing by motion compensation. Is.

  FIG. 12 is a block diagram showing a configuration example of a main part of a liquid crystal display device according to the seventh embodiment of the present invention. The liquid crystal display device includes an FRC unit 10, a decoding unit 21, a motion amount determination unit 14, and a control unit 15. , The switching unit 16, the electrode driving unit 18, the liquid crystal display panel 19, a path 20 for bypassing the FRC unit 10, and a black level signal insertion processing unit 24 on the path 20. The switching unit 16 is provided in the preceding stage of the FRC unit 10 and switches whether to input an input image signal to the FRC unit 10 or to the route 20 in accordance with an instruction from the control unit 15.

  The motion amount determination unit 14 uses the motion vector information output from the decoding unit 21 to determine whether the motion amount between frames of the input image signal is greater than a predetermined value.

  When the motion amount determination unit 14 determines that the motion amount between frames of the input image signal is larger than the predetermined value, the control unit 15 switches the switching unit 16 to the path 20 side to bypass the FRC unit 10 and input The image signal is input to the black level signal insertion processing unit 24. The black level signal insertion processing unit 24, for example, compresses the input image signal on the time axis (frame rate conversion) using a memory, and inserts a predetermined monochrome image signal such as a black level signal between the input frames.

  Also, when the motion amount determination unit 14 determines that the motion amount between frames of the input image signal is smaller than a predetermined value, the switching unit 16 is switched to the FRC unit 10 side to perform FRC processing (motion Compensation frame interpolation process). Note that the switching unit 16 may be provided in the subsequent stage of the FRC unit 10 so that the output signal of the FRC unit 10 and the output signal of the black level signal insertion processing unit 24 are switched and output to the liquid crystal panel 19.

  In the present embodiment, the drive frequency of the liquid crystal display panel 19 is not changed and remains 120 Hz. That is, the frame rate (number of frames) of the display image signal input to the electrode driving unit 18 is always the same. When an image signal with a large amount of motion is input, the black level signal insertion processing unit 24 inserts a predetermined monochrome image signal such as a black level signal between frames of the input image signal, thereby A means for converting the number of frames of the signal is configured. As another embodiment of the black level signal insertion processing, the electrode driver 18 may be configured to apply a black writing voltage to the liquid crystal display panel 19 for a predetermined period (in this example, 1/120 second). Good.

  FIG. 13 is a diagram showing the relationship between input data and output data according to the sixth embodiment of the present invention. FIG. 13A shows input data to the path 20, and FIG. 13B shows output data from the path 20. As shown in FIG. 13A, when an input image signal (input data) is input to the path 20 at a frame frequency of 60 Hz, the display time per frame is about 16.7 ms. The input data is input to the black level signal insertion processing unit 24, and as shown in FIG. 13B, the black level signal (colored black in the figure) is used between frames (here, between frame A and frame B). Frame) is inserted and output.

  Thus, by inserting the black image signal between each frame of the input image signal, image quality degradation due to motion blur is improved, and further image quality degradation due to motion compensation error does not occur. In order to compensate for a decrease in display brightness due to shortening, it is necessary to increase the light emission brightness of a backlight (not shown) provided on the back surface of the liquid crystal display panel 19.

  The liquid crystal display panel 19 displays the output data with the black level signal inserted at a drive frequency of 120 Hz. Since the number of frames is converted by inserting the black level signal, the display time per frame at this time is about 8.3 ms.

  As described above, during normal moving image display, the motion compensation type FRC process can improve the moving image quality, and when an image signal having a motion amount between frames larger than a predetermined value is input, By not performing interpolation processing by motion compensation on the image signal, motion vector detection errors due to large amount of motion between frames, motion compensation errors, etc. are eliminated, and motion compensation type FRC processing is performed. The resulting image quality degradation can be effectively prevented. Further, in this case, since the monochrome image signal is inserted and the frame rate is converted, it is not necessary to change the driving frequency of the liquid crystal display panel 19. In this case, since it is possible to approximate the impulse display method by inserting a monochrome image signal, it is possible to maintain the moving image quality improvement effect.

  In addition to the above embodiment, when the amount of motion between frames of the input image signal is larger than a predetermined value, the original image of the input frame is divided into a plurality of frame images at a predetermined luminance ratio, and the frame rate By performing the conversion, the moving image quality improvement effect may be maintained while preventing the image quality deterioration due to the motion compensation type FRC processing.

(Eighth embodiment)
The eighth embodiment of the present invention is configured to vary the compensation strength of the motion compensation processing in the interpolation frame generation unit when the amount of motion between frames of the input image signal is larger than a predetermined value. Specifically, the image processing apparatus includes an interpolation frame generation unit that generates an interpolation frame by weighted addition of the image signal subjected to the motion compensation process and the image signal subjected to the linear interpolation process at a predetermined ratio. When an image signal having an inter-movement amount greater than a predetermined value is input, the weighted addition ratio is varied.

  FIG. 14 is a block diagram illustrating a configuration example of a main part of the FRC unit 10 according to the eighth embodiment of the present invention. The frame generation unit 12 of the FRC unit 10 includes an interpolation frame memory 12a and an interpolation frame generation unit. 12b, and a compensation strength varying unit 12e that varies the compensation strength of the motion compensation processing in the FRC unit 10. In the figure, V is an interpolation vector, α is a frame interpolation ratio, and β is a compensation strength (weighted addition ratio).

  In general, as a method of frame interpolation processing, for example, frame interpolation by linear interpolation between two frames and frame interpolation (motion compensation interpolation) using a motion vector are known. In the former, an interpolation frame is obtained by performing linear interpolation with a frame interpolation ratio α from the signal of the previous frame and the signal of the current frame. Therefore, if this linear interpolation is used, it is possible to prevent image quality degradation due to motion compensation errors in the FRC process.

  On the other hand, in the latter, in order to obtain an interpolation frame from the previous frame and the current frame, an interpolation vector V is detected from a motion vector between the previous frame image and the current frame image, and the value (interpolation vector V) is obtained. An interpolation frame is obtained by weighted addition of a signal obtained by shifting the previous frame image by the magnitude of αV divided by the frame interpolation ratio α and a signal obtained by shifting the current frame image by (1-α) V. If this motion compensation type interpolation process is used, the moving image itself is captured and compensated, so that it is possible to obtain a good image quality without degradation in resolution. The image quality of large images may deteriorate.

  Therefore, in the present embodiment, the frame generation unit 12 is provided with a compensation intensity varying unit 12e. The compensation strength varying unit 12e varies the weighted addition ratio β when the motion amount determination unit 14 determines that the motion amount between frames of the input image signal is greater than a predetermined value. This weighted addition ratio β is a ratio at the time of weighted addition of the image signal subjected to the motion compensation process and the image signal subjected to the linear interpolation process. The interpolation frame generation unit 12b of the present embodiment generates an interpolation frame by weighted addition of linear interpolation and motion compensation interpolation according to the weighted addition ratio β.

  For example, when the amount of motion between frames of the input image signal is larger than a predetermined value, the compensation strength varying unit 12e sets the weighted addition ratio β = 0 and uses the image signal subjected to linear interpolation processing as an interpolation frame to perform motion compensation. Prevent image quality degradation due to errors. On the other hand, when the amount of motion between frames of the input image signal is smaller than a predetermined value, the weighted addition ratio β = 1, and the image signal subjected to motion compensation processing is made an interpolated frame to improve the quality of the moving image.

  Further, since the weighted addition ratio β can be arbitrarily set, it may be set to a substantially intermediate value between 0 and 1. As a result, while performing motion compensation in the interpolated frame image, it is possible to control so as to suppress degradation in image quality due to motion compensation errors. Both image quality degradation due to motion blur and image quality degradation due to motion compensation errors can be controlled. Can be improved appropriately.

  In this way, when an image signal having a motion amount between frames larger than a predetermined value is input, the strength of motion compensation processing in FRC can be varied (can be weakened). It is possible to reduce the influence of motion vector detection errors, motion compensation errors, and the like due to the largeness, and to effectively suppress image quality degradation caused by motion compensation type FRC processing.

  In each of the above-described embodiments, a frame that is determined to have a large amount of motion between frames of the input image signal and a frame that is determined to have a small amount of motion between frames of the input image signal are frequently switched. In order to prevent this, a predetermined value for determining whether or not the amount of motion with respect to the current frame is large may be varied based on information about whether or not the amount of motion is determined to be large in the previous frame.

  For example, when it is determined that the amount of motion between frames of the input image signal is large in the previous frame, the predetermined value is set to be large, and when the amount of motion between frames of the input image signal is determined to be small in the previous frame Sets the predetermined value small. In other words, hysteresis may be added to the determination as to whether or not the amount of motion between frames of the input image signal is large.

  Further, in order to prevent frequent switching between a frame determined to have a large amount of motion between frames of the input image signal and a frame determined to have a small amount of motion between frames of the input image signal, the input image is once set. When it is determined that the amount of motion between the frames of the signal is large, the determination result is continuously output over a predetermined number of frame periods, and thereafter, the amount of motion between the frames of the input image signal is increased for several frame periods. Processing may be performed assuming that the frame is a large frame.

  FIG. 15 is a flowchart for explaining an example of an image display method by the image display apparatus of the present invention. Here, an example of the image display method in the first to third embodiments will be described. First, the image display apparatus determines whether or not the amount of motion between frames of the input image signal is larger than a predetermined value (step S1), and when it is determined that the amount of motion between frames is an image signal larger than a predetermined value ( In the case of YES), the motion compensation process of the FRC unit 10 is invalidated by setting the motion vector or the interpolation vector to 0 vector (step S2). If it is determined in step S1 that the amount of motion between frames is an image signal smaller than a predetermined value (NO), the motion compensation process of the FRC unit 10 is executed as usual (step S3). The image signal with the frame frequency converted in this way is displayed and output from the liquid crystal display panel 19 (step S4).

  FIG. 16 is a flowchart for explaining another example of the image display method by the image display apparatus of the present invention. Here, examples of image display methods in the fourth to seventh embodiments will be described. First, the image display device determines whether or not the amount of motion between frames of the input image signal is larger than a predetermined value (step S11), and when it is determined that the amount of motion between frames is an image signal larger than a predetermined value. (In the case of YES), the motion compensation frame interpolation process of the FRC unit 10 is bypassed, and the input image signal is input to another path 20 (step S12).

  Here, in the bypassed path 20, inter-frame interpolation of an image signal subjected to linear interpolation processing, inter-frame insertion of an image signal of the same frame, inter-frame insertion of a predetermined monochromatic image signal such as a black level signal The image signal subjected to the frame rate conversion is output by performing any one of the above processes, or the input image signal is output as it is and the process of changing the drive frequency of the liquid crystal display panel 19 is performed.

  If it is determined in step S11 that the amount of motion between frames is an image signal smaller than a predetermined value (in the case of NO), an image signal subjected to interpolation processing by motion compensation in the FRC unit 10 is output. (Step S13). Finally, an image is displayed and output from the liquid crystal display panel 19 (step S14).

  FIG. 17 is a flowchart for explaining another example of the image display method by the image display apparatus of the present invention. Here, an example of the image display method in the above-described eighth embodiment will be described. First, the image display device determines whether or not the amount of motion between frames of the input image signal is an image signal greater than a predetermined value (step S21), and if the amount of motion between frames is greater than a predetermined value. If determined (YES), the strength of the motion compensation process in the FRC unit 10 is varied (weak) (step S22). If it is determined that the amount of motion between frames is an image signal smaller than a predetermined value (in the case of NO), the strength of motion compensation processing in the FRC unit 10 is increased as usual (step S23). The image signal with the frame frequency converted in this way is displayed and output from the liquid crystal display panel 19 (step S24).

  As described above, according to the present invention, when the amount of motion between frames of the input image signal is larger than a predetermined value, the motion compensation processing in the frame rate conversion (FRC) unit can be invalidated and displayed. Therefore, it is possible to effectively prevent image quality degradation due to motion compensation errors.

  Next, still another embodiment of the image display device of the present invention will be described. In the present embodiment, FRC is used only for a pixel in which the motion amount between frames of the input image signal is larger than a predetermined value or a region including the pixel, by using means such as invalidating motion compensation processing in the FRC unit 10. The main purpose is to prevent image quality degradation in a region where the amount of motion between frames due to processing is large.

(Ninth embodiment)
In the ninth embodiment of the present invention, in order to invalidate the motion compensation processing of the FRC unit 10 for a pixel in which the motion amount between frames of the input image signal is larger than a predetermined value or a region including the pixel, An interpolation vector of an interpolation block having an inter-motion amount larger than a predetermined value is set to 0 vector so that interpolation between pixels at different positions by that portion does not occur.

  FIG. 18 is a block diagram showing a configuration example of a main part of a liquid crystal display device according to the ninth embodiment of the present invention. The liquid crystal display device includes an FRC unit 10, a control unit 15, an electrode driving unit 18, and a liquid crystal display panel. 19. The FRC unit 10 includes a motion vector detection unit 11e, an interpolation vector evaluation unit 11f, an interpolation frame generation unit 12b, and a time base conversion unit 12d, and further inserts an interpolation vector assigned by the interpolation vector evaluation unit 11f. An interpolation vector memory 12f that accumulates for each insertion block is provided.

  The motion vector detection unit 11e outputs a motion vector detected by a predetermined calculation, and the vector calculated during the motion vector detection calculation exceeds the predetermined vector evaluation calculation range set in the interpolation vector evaluation unit 11f. For this reason, the OB flag “1” is output to a block that has been subjected to some special processing described above with reference to FIGS.

  The control unit 15 applies to the pixel to which the OB flag “1” indicating that the predetermined vector evaluation calculation range is exceeded during the motion vector detection calculation by the motion vector detection unit 11e or a region including the pixel. Then, control is performed so as to invalidate the motion compensation processing in the FRC unit 10. In other words, the liquid crystal display device according to the present embodiment is based on the OB flag information output from the motion vector detection unit 11e, with respect to a pixel in which the motion amount between frames of the input image signal is greater than a predetermined value or a region including the pixel. Thus, the motion compensation process of the FRC unit 10 is controlled to be invalidated.

  As described above, the liquid crystal display panel 19 is an active matrix liquid crystal display having a liquid crystal layer and electrodes for applying scanning signals and data signals to the liquid crystal layer. The electrode drive unit 18 is a display driver for driving the scan electrodes and data electrodes of the liquid crystal display panel 19 based on the image signal whose frame rate is converted by the FRC unit 10.

  The drive frequency of the liquid crystal display panel 19 is the frame frequency converted by the FRC unit 10. Therefore, when an image signal input at a frame frequency of 60 Hz is converted to a frame frequency of 120 Hz by the FRC unit 10, the drive frequency of the liquid crystal display panel 19 is 120Hz.

  In FIG. 18, the interpolation vector memory 12 f stores the interpolation vector allocated by the interpolation vector evaluation unit 11 f for each interpolation block. When there is an OB flag “1” that means that the vector calculated during the motion vector detection calculation exceeds the predetermined vector evaluation calculation range, the control unit 15 accesses the interpolation vector memory 12f and moves the motion vector. The interpolation vector of the interpolation block corresponding to the pixel area where the vector calculated during the detection calculation exceeds the predetermined vector evaluation calculation range is set to 0 vector. For an interpolation block corresponding to a pixel area in which the vector calculated during the motion vector detection calculation falls within a predetermined vector evaluation calculation range, the interpolation frame generation unit directly uses the interpolation vector in the interpolation vector memory 12f. Input to 12b.

  That is, when accessing the interpolation vector memory 12f, the control unit 15 gives flag information to an interpolation block corresponding to a pixel whose amount of motion between frames is greater than a predetermined value or a region including the pixel. This flag information is a flag for preventing the interpolation vector of the interpolation block from being used. For the interpolation block to which this flag information is assigned, the output of the interpolation vector is 0. Control. Thus, by setting the interpolation vector in the interpolation vector memory 12f to 0, it is possible to prevent motion compensation interpolation.

  As described above, when a normal moving image is displayed, the motion compensation type FRC processing can improve the moving image quality, and the input image signal includes a pixel region in which the amount of motion between frames is larger than a predetermined value. Disables motion compensation processing for the pixel area, thereby eliminating motion vector detection errors and motion compensation errors due to a large amount of motion between frames, and image quality degradation caused by motion compensation type FRC processing. Can be effectively prevented.

(Tenth embodiment)
In the tenth embodiment of the present invention, in order to invalidate the motion compensation processing of the FRC unit 10 for a pixel having a motion amount between frames of an input image signal larger than a predetermined value or a region including the pixel, An interpolation vector of an interpolation block having an inter-motion amount larger than a predetermined value is set to 0 vector so that interpolation between pixels at different positions by that portion does not occur.

  FIG. 19 is a block diagram showing a configuration example of a main part of a liquid crystal display device according to the tenth embodiment of the present invention. The liquid crystal display device includes an FRC unit 10, a control unit 15, an electrode driving unit 18, and a liquid crystal display panel. 19. The FRC unit 10 includes a motion vector detection unit 11e, an interpolation vector evaluation unit 11f, an interpolation frame generation unit 12b, and a time base conversion unit 12d, and further inserts an interpolation vector assigned by the interpolation vector evaluation unit 11f. An interpolation vector memory 12f that accumulates for each insertion block is provided.

  The motion vector detection unit 11e determines whether the motion vector detected by the predetermined calculation and the vector calculated during the motion vector detection calculation exceed the predetermined vector evaluation calculation range set in the interpolation vector evaluation unit 11f. Is output to the interpolation vector evaluation unit 11f.

  Based on the OB flag information for each interpolation block output by the interpolation vector evaluation unit 11f, the control unit 15 applies the FRC unit to a pixel to which the OB flag “1” is assigned or a region including the pixel. 10 is controlled so as to invalidate the motion compensation processing in step 10. In other words, the liquid crystal display device according to the present embodiment performs control so as to invalidate the motion compensation processing of the FRC unit 10 for a pixel in which the amount of motion between frames in the input image signal is greater than a predetermined value or a region including the pixel. To do.

  The interpolation vector evaluation unit 11f evaluates the motion vector output by the motion vector detection unit 11e, and assigns an optimal interpolation vector for each interpolation block. Specifically, an equivalent motion vector is assigned to the interpolation block to which the motion vector points from the detected block. However, the allocated interpolation block may be indicated by a detection block different from the detected block. That is, a plurality of motion vectors may be assigned to one interpolation block. In such a case, DFD is calculated for each of a plurality of motion vectors, and a motion vector having the smallest DFD (that is, more correct) is adopted and assigned.

  At this time, OB flag information corresponding to the allocated motion vector is also allocated for each interpolation block.

  In FIG. 19, the interpolation vector memory 12f stores the interpolation vector allocated by the interpolation vector evaluation unit 11f for each interpolation block. When the OB flag “1” exists based on the OB flag information given to each interpolation block output from the interpolation vector evaluation unit 11f, the control unit 15 accesses the interpolation vector memory 12f and The interpolation vector of the insertion block is set to 0 vector. For the interpolation block to which the OB flag “0” is assigned, the interpolation vector in the interpolation vector memory 12f is directly input to the interpolation frame generation unit 12b.

  That is, when accessing the interpolation vector memory 12f, the control unit 15 performs interpolation vector interpolation for an interpolation block corresponding to a pixel whose amount of motion between frames is greater than a predetermined value or a region including the pixel. Control the output to be zero. Thus, by setting the interpolation vector in the interpolation vector memory 12f to 0, it is possible to prevent motion compensation interpolation.

  As described above, when a normal moving image is displayed, the motion compensation type FRC processing can improve the moving image quality, and the input image signal includes an image region in which the amount of motion between frames is larger than a predetermined value. Disables motion compensation processing for the image area, thereby eliminating motion vector detection errors, motion compensation errors, etc. due to a large amount of motion between frames, and image quality degradation caused by motion compensation type FRC processing. Can be effectively prevented.

(Eleventh embodiment)
In the eleventh embodiment of the present invention, in order to invalidate the motion compensation processing of the FRC unit 10 for a pixel having a motion amount between frames of an input image signal larger than a predetermined value or a region including the pixel, An interpolation vector of an interpolation block having an inter-motion amount larger than a predetermined value is set to 0 vector so that interpolation between pixels at different positions by that portion does not occur.

  FIG. 20 is a block diagram showing a configuration example of a main part of a liquid crystal display device according to the eleventh embodiment of the present invention. The liquid crystal display device includes an FRC unit 10, a control unit 15, an electrode driving unit 18, and a liquid crystal display panel. 19. The FRC unit 10 includes a motion vector detection unit 11e, an interpolation vector evaluation unit 11f, an interpolation frame generation unit 12b, and a time base conversion unit 12d.

  The motion vector detection unit 11e outputs a motion vector detected by a predetermined calculation, and the vector calculated during the motion vector detection calculation exceeds the predetermined vector evaluation calculation range set in the interpolation vector evaluation unit 11f. For this reason, the OB flag “1” is output to a block that has been subjected to some special processing described above with reference to FIGS.

  Based on the OB flag information output from the motion vector detection unit 11e, the control unit 15 invalidates the motion compensation processing in the FRC unit 10 for a pixel to which the OB flag “1” is assigned or a region including the pixel. To control. In other words, the liquid crystal display device according to the present embodiment performs control so as to invalidate the motion compensation processing of the FRC unit 10 for a pixel in which the amount of motion between frames in the input image signal is greater than a predetermined value or a region including the pixel. To do.

  In FIG. 20, an interpolation frame generation unit 12b generates an interpolation frame from the interpolation vector assigned by the interpolation vector evaluation unit 11f. When there is an OB flag “1” indicating that the vector calculated during the motion vector detection calculation exceeds the predetermined vector evaluation calculation range, the control unit 15 accesses the interpolation frame generation unit 12b to The interpolation vector of the interpolation block corresponding to the pixel area where the vector calculated during the vector detection calculation exceeds the predetermined vector evaluation calculation range is set to 0 vector.

  For an interpolation block corresponding to a pixel area in which the vector calculated during the motion vector detection calculation falls within a predetermined vector evaluation calculation range, the interpolation frame generation unit 12b generates an interpolation frame from the interpolation vector. To do.

  That is, the control unit 15 passes information (coordinate position, region information, etc.) indicating which interpolation block (or which pixel) has a motion amount larger than a predetermined value to the interpolation frame generation unit 12b to generate an interpolation frame. The unit 12b sets the interpolation vector of the corresponding pixel or the interpolation block including the pixel to 0 vector according to the instruction from the control unit 15.

  As described above, during normal moving image display, motion compensation processing can be performed on a pixel having a motion amount between frames larger than a predetermined value or an area including the pixel, while the motion quality can be improved by motion compensation type FRC processing. By disabling, motion vector detection errors due to a large amount of motion between frames, motion compensation errors, and the like can be eliminated, and image quality degradation caused by motion compensation type FRC processing can be effectively prevented. .

(Twelfth embodiment)
In the twelfth embodiment of the present invention, in order to invalidate the motion compensation processing of the FRC unit 10 for a pixel having a motion amount between frames of an input image signal larger than a predetermined value or a region including the pixel, An interpolation vector of an interpolation block having an inter-motion amount larger than a predetermined value is set to 0 vector so that interpolation between pixels at different positions by that portion does not occur.

  FIG. 21 is a block diagram showing a configuration example of a main part of a liquid crystal display device according to the twelfth embodiment of the present invention. The liquid crystal display device includes an FRC unit 10, a control unit 15, an electrode driving unit 18, and a liquid crystal display panel. 19. The FRC unit 10 includes a motion vector detection unit 11e, an interpolation vector evaluation unit 11f, an interpolation frame generation unit 12b, and a time base conversion unit 12d.

  The motion vector detection unit 11e includes a motion vector detected by a predetermined calculation and OB flag information for each block indicating whether or not the vector calculated during the motion vector detection calculation exceeds a predetermined vector evaluation calculation range. And output to the interpolation vector evaluation unit 11f.

  Based on the OB flag information for each interpolation block output by the interpolation vector evaluation unit 11f, the control unit 15 applies the FRC unit to a pixel to which the OB flag “1” is assigned or a region including the pixel. 10 is controlled so as to invalidate the motion compensation processing in step 10. In other words, the liquid crystal display device according to the present embodiment performs control so as to invalidate the motion compensation processing of the FRC unit 10 for a pixel in which the amount of motion between frames in the input image signal is greater than a predetermined value or a region including the pixel. To do.

  The interpolation vector evaluation unit 11f evaluates the motion vector output by the motion vector detection unit 11e, and assigns an optimal interpolation vector for each interpolation block. Specifically, an equivalent motion vector is assigned to the interpolation block to which the motion vector points from the detected block. However, the allocated interpolation block may be indicated by a detection block different from the detected block. That is, a plurality of motion vectors may be assigned to one interpolation block. In such a case, DFD is calculated for each of a plurality of motion vectors, and a motion vector having the smallest DFD (that is, more correct) is adopted and assigned.

  At this time, OB flag information corresponding to the allocated motion vector is also allocated for each interpolation block.

  In FIG. 21, the interpolation frame generation unit 12b generates an interpolation frame from the interpolation vector assigned by the interpolation vector evaluation unit 11f. When the OB flag “1” exists based on the OB flag information assigned to each interpolation block output from the interpolation vector evaluation unit 11f, the control unit 15 accesses the interpolation frame generation unit 12b, and The interpolation vector of the interpolation block is set to 0 vector. For the interpolation block to which the OB flag “0” is assigned, the interpolation frame generation unit 12b generates an interpolation frame from the interpolation vector.

  That is, the control unit 15 passes information (coordinate position, region information, etc.) indicating which interpolation block (or which pixel) has a motion amount larger than a predetermined value to the interpolation frame generation unit 12b to generate an interpolation frame. The unit 12b sets the interpolation vector of the corresponding pixel or the interpolation block including the pixel to 0 vector according to the instruction from the control unit 15.

  As described above, during normal moving image display, motion compensation processing can be performed on a pixel having a motion amount between frames larger than a predetermined value or an area including the pixel, while the motion quality can be improved by motion compensation type FRC processing. By disabling, motion vector detection errors due to a large amount of motion between frames, motion compensation errors, and the like can be eliminated, and image quality degradation caused by motion compensation type FRC processing can be effectively prevented. .

  In the ninth to twelfth embodiments described above, in order to invalidate the motion compensation processing in the FRC unit 10 for a pixel having a large amount of motion between frames of the input image signal or a region including the pixel. When the motion vector or the interpolation vector is set to 0 vector, the boundary between the area where the motion compensation processing is invalidated and the area where the motion amount between the frames of the input image signal is determined to be small and the motion compensation processing is performed In the portion, since the vector changes suddenly, the presence or absence of this motion compensation processing clearly appears in the image and may stand out.

  In order to remedy this problem, a low pass filter is applied to a boundary portion between a pixel having a large amount of motion between frames of the input image signal or a region including the pixel and a pixel having a small amount of motion or a region including the pixel. It is desirable to continuously change the intensity of the motion compensation process by performing a filtering process such as the above.

  In this way, by continuously changing the intensity of the motion compensation process, the interpolated image of the boundary portion between the region where the amount of motion is large and the region where the amount of motion is small can be made a smooth continuous image, and this boundary is noticeable. Can be suppressed. In the following embodiments as well, it is desirable to continuously change the intensity of motion compensation processing by performing filter processing on the boundary portion between a region with a large amount of motion and other regions.

(13th Embodiment)
The thirteenth embodiment of the present invention includes a linear interpolation processing unit on a path different from the input path to the FRC unit 10, and the amount of motion between frames of the input image signal is larger than a predetermined value or the pixel The region including the pixels is switched to the linear interpolation processing unit, and an image signal subjected to linear interpolation is inserted only in a portion where the motion amount between frames is larger than a predetermined value. That is, for a pixel having a motion amount between frames larger than a predetermined value or an area including the pixel, the frame rate is converted by performing a linear interpolation process instead of performing an interpolation process by motion compensation. To switch to.

  FIG. 22 is a block diagram showing a configuration example of main parts of a liquid crystal display device according to a thirteenth embodiment of the present invention. The liquid crystal display device includes an FRC unit 10, a decoding unit 21, a motion amount determination unit 14, and a control unit 15. , The switching unit 25, and a path 26 provided separately from the input path to the FRC unit 10, and a linear interpolation interpolation processing unit 27 on the path 26. In addition, description of the electrode drive part 18 and the liquid crystal display panel 19 is abbreviate | omitted. The switching unit 25 is provided in a subsequent stage of the FRC unit 10 and outputs an image signal (motion compensated image) from the FRC unit 10 or an image signal from the linear interpolation processing unit 27 in accordance with an instruction from the control unit 15. Switch whether to output (linear interpolation image).

  Here, when the input image signal is a compressed input signal (for example, MPEG, DivX, etc.) compressed using motion vector information or the like, the compressed input signal is restored to the image signal by the decoding unit 21 and FRC is used. Input to the unit 10. At this time, when the input image signal is compressed using the motion vector information, the motion vector used for the restoration can be extracted from the decoding unit 21. In the present embodiment, based on the extracted motion vector, the motion amount determination unit 14 determines a pixel in which the motion amount between frames of the input image signal is greater than a predetermined value or a region including the pixel.

  The motion amount determination unit 14 determines a pixel in which the length of the motion vector output from the decoding unit 21 is greater than a predetermined threshold or a region including the pixel. The control unit 15 passes the switching unit 25 through a path 26 (linear interpolation) for a pixel or a region including the pixel in which the motion amount between frames of the input image signal is determined by the motion amount determination unit 14 to be larger than a predetermined value. Switching to the interpolation processing unit 27) side, the display image signal generated by interpolating the image signal subjected to the linear interpolation process between the frames of the input image signal is output to the display panel.

  The linear interpolation processing unit 27 performs processing for inserting an interpolation frame subjected to linear interpolation processing between frames of the input image signal.

  In addition, for a pixel in which the amount of motion between frames of the input image signal is larger than a predetermined value or an area not including the pixel, the switching unit 25 is switched to the FRC unit 10 side to perform FRC processing between the frames of the input image signal. The display image signal subjected to (motion compensation frame interpolation processing) is output to the display panel.

  As described in Non-Patent Document 2 above, the linear interpolation process obtains an interpolation frame by performing linear interpolation with a frame interpolation ratio α from the signal of the previous frame and the signal of the current frame. Is.

  As described above, during normal moving image display, motion compensation type FRC processing can improve moving image quality, and the amount of motion between frames of an input image signal is greater than a predetermined value or a region including the pixel. By disabling the motion compensation processing for, motion vector detection errors and motion compensation errors due to the large amount of motion between frames are eliminated, and image quality degradation due to motion compensation type FRC processing is effectively prevented. can do.

(Fourteenth embodiment)
In the fourteenth embodiment of the present invention, a memory is provided on a path different from the input path to the FRC unit 10, and the movement amount between frames of the input image signal is larger than a predetermined value or an area including the pixels. On the other hand, switching to the memory side is performed, and only the portion where the amount of motion between frames is larger than a predetermined value is repeatedly read out from the memory at a plurality of times at a high speed to convert the frame rate. That is, for a pixel with a motion amount between frames larger than a predetermined value or an area including the pixel, frame rate conversion is performed by performing high-speed continuous output of an input image signal instead of performing interpolation processing by motion compensation. It is a thing to switch to.

  FIG. 23 is a block diagram showing a configuration example of a main part of a liquid crystal display device according to the fourteenth embodiment of the present invention. The liquid crystal display device includes an FRC unit 10, a decoding unit 21, a motion amount determination unit 14, and a control unit 15. The switching unit 25 is further provided with a path 26 provided separately from the input path to the FRC unit 10 and a memory 28 on the path 26. In addition, description of the electrode drive part 18 and the liquid crystal display panel 19 is abbreviate | omitted. The switching unit 25 is provided at a subsequent stage of the FRC unit 10 and outputs an image signal (motion compensated image) from the FRC unit 10 according to an instruction from the control unit 15, or an image of a previous frame or a subsequent frame from the memory 28. Switches whether to output a signal.

  The motion amount determination unit 14 determines a pixel in which the length of the motion vector output from the decoding unit 21 is greater than a predetermined threshold or a region including the pixel.

  The control unit 15 passes the switching unit 25 to the path 26 (memory 28) for a pixel or a region including the pixel, in which the motion amount between frames of the input image signal is determined by the motion amount determination unit 14 to be larger than a predetermined value. The display image signal of the previous frame or the subsequent frame is output to the display panel between the frames of the input image signal.

  An input image signal is accumulated in the memory 28, and an image signal of a pixel having a large amount of motion between frames of the input image signal or an area including the pixel is repeatedly read out.

  In addition, for a pixel in which the amount of motion between frames of the input image signal is larger than a predetermined value or an area not including the pixel, the switching unit 25 is switched to the FRC unit 10 side to perform FRC processing between the frames of the input image signal. The display image signal subjected to (motion compensation frame interpolation processing) is output to the display panel.

  As described above, during normal moving image display, motion compensation type FRC processing can improve moving image quality, and motion compensation for pixels having a large amount of motion between frames of an input image signal or a region including the pixels. By disabling the processing, it is possible to eliminate motion vector detection errors, motion compensation errors, and the like due to a large amount of motion between frames, and effectively prevent image quality degradation caused by motion compensation type FRC processing. it can.

(Fifteenth embodiment)
In the fifteenth embodiment of the present invention, the compensation intensity of the motion compensation processing in the interpolation frame generation unit is variable for a pixel in which the motion amount between frames of the input image signal is greater than a predetermined value or a region including the pixel. Configured to do. Specifically, the image processing apparatus includes an interpolation frame generation unit that generates an interpolation frame by weighted addition of the image signal subjected to the motion compensation process and the image signal subjected to the linear interpolation process at a predetermined ratio. The weighted addition ratio is varied for a pixel whose amount of motion is greater than a predetermined value or a region including the pixel.

  FIG. 24 is a block diagram illustrating a configuration example of a main part of the FRC unit 10 according to the fifteenth embodiment of the present invention. The frame generation unit 12 of the FRC unit 10 includes an interpolation frame memory 12a and an interpolation frame generation unit. 12b, and further includes a compensation strength variable unit 12g that varies the compensation strength of the motion compensation processing in the FRC unit 10. In the figure, V is an interpolation vector, α is a frame interpolation ratio, and β is a compensation strength (weighted addition ratio).

  In general, as a method of frame interpolation processing, for example, frame interpolation by linear interpolation between two frames and frame interpolation (motion compensation interpolation) using a motion vector are known. In the former, an interpolation frame is obtained by performing linear interpolation with a frame interpolation ratio α from the signal of the previous frame and the signal of the current frame. Therefore, by using this linear interpolation, it is possible to effectively prevent image quality degradation caused by motion compensation type FRC processing due to a large amount of motion between frames.

  On the other hand, in the latter, in order to obtain an interpolation frame from the previous frame and the current frame, an interpolation vector V is detected from a motion vector between the previous frame image and the current frame image, and the value (interpolation vector V) is obtained. An interpolation frame is obtained by weighted addition of a signal obtained by shifting the image of the previous frame by the amount of αV divided by the frame interpolation ratio α and a signal obtained by shifting the image of the current frame by (α−1) V. If this motion compensation interpolation is used, the moving image itself is captured and compensated, so that there is no degradation in resolution and good image quality can be obtained. The image quality may deteriorate due to a motion vector detection error or the like.

  Therefore, in the present embodiment, the frame generation unit 12 is provided with a compensation intensity varying unit 12g. The compensation intensity varying unit 12g varies the weighted addition ratio β for a pixel in which the motion amount between frames of the input image signal is determined to be greater than a predetermined value or a region including the pixel by the motion amount determination unit 14. This weighted addition ratio β is a ratio at the time of weighted addition of the image signal subjected to the motion compensation process and the image signal subjected to the linear interpolation process. In accordance with the weighted addition ratio β, the interpolation frame generation unit 12b according to the present embodiment performs linear interpolation interpolation and motion for a pixel whose amount of motion between frames of the input image signal is greater than a predetermined value or a region including the pixel. An interpolation frame is generated by weighted addition of the compensation interpolation.

  For example, the compensation intensity varying unit 12g sets the weighted addition ratio β = 0 to a pixel whose amount of motion between frames of the input image signal is greater than a predetermined value or a region including the pixel, and that has undergone linear interpolation processing. The interpolated frame is used to prevent image quality deterioration in a portion with a large amount of motion. In addition, a moving image is obtained by setting a weighted addition ratio β = 1 for a pixel in which a motion amount between frames of an input image signal is greater than a predetermined value or a region not including the pixel, and using an image signal subjected to motion compensation processing as an interpolation frame. Make the quality good.

  Further, since the weighted addition ratio β can be arbitrarily set, it may be set to a substantially intermediate value between 0 and 1. As a result, while performing motion compensation in the interpolated frame image, it is possible to control so that the image quality of the portion where the motion amount between the frames of the input image signal is larger than the predetermined value is not deteriorated. It is possible to appropriately improve both the image quality degradation due to the large amount of motion in between. Note that the compensation intensity varying process in the FRC unit 10 may be performed by either a method performed in units of pixels or a method performed in units of blocks (regions).

  In this way, the compensation intensity of the motion compensation processing in the FRC can be varied (decreased) for a pixel having a large amount of motion between frames of the input image signal or a region including the pixel. Therefore, it is possible to reduce the influence of motion vector detection error, motion compensation error, and the like due to a large amount of motion, and to effectively suppress image quality degradation caused by motion compensation type FRC processing.

  In each of the above-described embodiments, a pixel determined to have a large amount of motion between frames of the input image signal or a region including the pixel and a pixel determined to have a small amount of motion between frames of the input image signal or In order to prevent frequent switching to the region including the pixel, a predetermined value for determining whether or not the amount of motion is large relative to the current frame is used as information on whether or not the amount of motion is determined to be large in the previous frame. It may be made variable based on this.

  For example, for a pixel determined to have a large amount of motion between frames of the input image signal in the previous frame or an area including the pixel, the predetermined value is set large, and the amount of motion between frames of the input image signal in the previous frame For a pixel determined to be small or a region including the pixel, the predetermined value is set small. In other words, hysteresis may be added to the determination as to whether or not the amount of motion between frames of the input image signal is large.

  In addition, a pixel determined to have a large amount of motion between frames of the input image signal or a region including the pixel, and a pixel determined to have a small amount of motion between frames of the input image signal or a region including the pixel. In order to prevent frequent switching, for a pixel that has been determined to have a large amount of motion between frames of the input image signal or a region including the pixel, the determination result is continuously output over a predetermined number of frame periods. Thus, thereafter, the process may be performed on the assumption that the amount of motion between frames of the input image signal is large for a period of several frames.

  FIG. 25 is a flowchart for explaining another example of the image display method by the image display apparatus of the present invention. Here, examples of image display methods in the ninth to twelfth embodiments will be described. First, the image display device determines whether or not the amount of motion between frames of the input image signal is a pixel (or block) greater than a predetermined value (step S1), and the amount of motion between frames is greater than a predetermined value (or block). ) Is determined (in the case of YES), the FRC unit 10 sets the interpolation vector of a pixel in which the amount of motion between frames is greater than a predetermined value or an area including the pixel (interpolation block) to 0 vector. Is partially invalidated (step S2).

  Further, when it is determined in step S1 that the amount of motion between frames is a pixel (or block) smaller than a predetermined value (in the case of NO), an image signal subjected to interpolation processing by motion compensation in the FRC unit 10 is output. (Step S3). The image signal with the frame frequency converted in this way is displayed and output from the liquid crystal display panel 19 (step S4).

  FIG. 26 is a flowchart for explaining another example of the image display method by the image display apparatus of the present invention. Here, an example of the image display method in the thirteenth embodiment will be described. First, the image display device determines whether or not the amount of motion between frames of the input image signal is a pixel (or block) greater than a predetermined value (step S11), and the amount of motion between frames is greater than a predetermined value (or block). ) Is determined (in the case of YES), an image signal obtained by interpolating a linearly interpolated image is output for a pixel in which the amount of motion between frames is greater than a predetermined value or an area including the pixel (interpolated block). By doing so, the motion compensation interpolation processing of the FRC unit 10 is not partially performed (step S12).

  In step S11, when it is determined that the amount of motion between frames is a pixel (or block) smaller than a predetermined value (in the case of NO), an image signal subjected to interpolation processing by motion compensation in the FRC unit 10 is output. (Step S13). The image signal with the frame frequency converted in this way is displayed and output from the liquid crystal display panel 19 (step S14).

  FIG. 27 is a flowchart for explaining another example of the image display method by the image display apparatus of the present invention. Here, an example of the image display method in the fourteenth embodiment will be described. First, the image display apparatus determines whether or not the amount of motion between frames of the input image signal is a pixel (or block) greater than a predetermined value (step S21), and the amount of motion between frames is greater than a predetermined value (or block). ) Is determined (in the case of YES), an image signal in which a previous or subsequent frame image is inserted into a pixel having a motion amount between frames larger than a predetermined value or an area including the pixel (interpolation block) is obtained. By outputting, the motion compensation interpolation processing of the FRC unit 10 is not partially performed (step S22).

  If it is determined in step S21 that the amount of motion between frames is a pixel (or block) smaller than a predetermined value (NO), an image signal subjected to interpolation processing by motion compensation in the FRC unit 10 is output. (Step S23). The image signal with the frame frequency converted in this way is displayed and output from the liquid crystal display panel 19 (step S24).

  FIG. 28 is a flowchart for explaining another example of the image display method by the image display device of the present invention. Here, an example of the image display method in the fifteenth embodiment will be described. First, the image display apparatus determines whether or not the amount of motion between frames of the input image signal is a pixel (or block) greater than a predetermined value (step S31), and the amount of motion between frames is greater than a predetermined value (or block). ) Is determined (in the case of YES), the compensation intensity of the motion compensation process in the FRC unit 10 is applied to a pixel in which the motion amount between frames is greater than a predetermined value or a region (interpolation block) including the pixel. It is made variable (weak) (step S32).

  If it is determined in step S31 that the amount of motion between frames is a pixel (or block) smaller than a predetermined value (NO), the compensation strength of the motion compensation process in the FRC unit 10 is increased as usual (step S33). ). The image signal with the frame frequency converted in this way is displayed and output from the liquid crystal display panel 19 (step S34).

  As described above, according to the present invention, when the motion amount between frames of the input image signal partially includes a pixel region that is larger than the predetermined value, the pixel having the motion amount between the frames larger than the predetermined value. Alternatively, since the motion compensation processing in the frame rate conversion (FRC) unit can be partially invalidated and displayed for the region including the pixel, an image with a large amount of motion due to the interpolation processing by motion compensation It is possible to effectively prevent image quality degradation in the area.

  In the above-described embodiment, as an example of a method for determining whether or not the amount of motion between frames of the input image signal is larger than a predetermined value, a method using OB flag information, a motion included in input image data, or the like. Although the method using vector information has been described, the present invention is not limited to this, and various motion amount determination methods can be applied.

  For example, when the vector calculated during the motion vector detection calculation by the motion vector detection unit 11e exceeds the predetermined vector evaluation calculation range, the maximum value in the vector evaluation calculation range as described above with reference to FIG. If the clip is clipped, it is possible to determine that the amount of motion is excessive without using the OB flag information as described above.

  That is, when either the X component or the Y component of the motion vector output from the motion vector detection unit 11e is equal to the maximum value within the vector evaluation calculation range, the vector calculated during the motion vector detection calculation is a predetermined value. Since it can be considered that the vector evaluation calculation range has been exceeded, based on the length of the motion vector detected by the motion vector detection unit 11e, an image signal with a large amount of motion between frames or a pixel with a large amount of motion between frames Alternatively, an area including the pixel may be determined.

  Furthermore, in the above-described embodiment, when the vector evaluation calculation range is not limited, or when the vector evaluation calculation range is set wide, errors in motion vector detection often occur as described above. Even within the vector evaluation calculation range, if the length of the output motion vector is greater than a predetermined threshold, the amount of motion in the frame of the input image signal is assumed to be large by a predetermined value, and the image having a large amount of motion between frames A pixel having a large amount of motion between signals or frames or a region including the pixel may be determined.

  For example, when it is possible to detect panning of the camera, and related data such as camera parameters is added to the input image signal, an image signal with a large amount of motion between frames can be obtained by using this. May be determined.

  In the above description, an example of an embodiment related to the image processing apparatus and method of the present invention has been described. From these descriptions, an image processing program for executing the image processing method as a program by a computer, and the image A program recording medium in which the processing program is recorded on a computer-readable recording medium can be easily understood.

It is a block diagram which shows the structural example of the 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 liquid crystal display device which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the principal part structural example of the liquid crystal display device which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the principal part structural example of the liquid crystal display device which concerns on the 3rd Embodiment of this invention. It is a block diagram which shows the principal part structural example of the liquid crystal display device which concerns on the 4th Embodiment of this invention. It is a figure which shows the relationship between the input data and output data which concern on the 4th Embodiment of this invention. It is a block diagram which shows the principal part structural example of the liquid crystal display device which concerns on the 5th Embodiment of this invention. It is a figure which shows the relationship between the input data and output data which concern on the 5th Embodiment of this invention. It is a block diagram which shows the principal part structural example of the liquid crystal display device which concerns on the 6th Embodiment of this invention. It is a figure which shows the relationship between the input data and output data which concern on the 6th Embodiment of this invention. It is a block diagram which shows the principal part structural example of the FRC part which concerns on the 7th Embodiment of this invention. It is a figure which shows the relationship between the input data and output data which concern on the 7th Embodiment of this invention. It is a block diagram which shows the principal part structural example of the FRC part which concerns on the 8th Embodiment of this invention. It is a flowchart for demonstrating the other example of the image display method by the image display apparatus of this invention. It is a flowchart for demonstrating the other example of the image display method by the image display apparatus of this invention. It is a flowchart for demonstrating the other example of the image display method by the image display apparatus of this invention. It is a block diagram which shows the principal part structural example of the FRC part which concerns on the 9th Embodiment of this invention. It is a block diagram which shows the principal part structural example of the FRC part which concerns on the 10th Embodiment of this invention. It is a block diagram which shows the principal part structural example of the FRC part which concerns on the 11th Embodiment of this invention. It is a block diagram which shows the principal part structural example of the FRC part which concerns on the 12th Embodiment of this invention. It is a block diagram which shows the principal part structural example of the FRC part which concerns on the 13th Embodiment of this invention. It is a block diagram which shows the principal part structural example of the FRC part which concerns on the 14th Embodiment of this invention. It is a block diagram which shows the principal part structural example of the FRC part which concerns on the 15th Embodiment of this invention. It is a flowchart for demonstrating the other example of the image display method by the image display apparatus of this invention. It is a flowchart for demonstrating the other example of the image display method by the image display apparatus of this invention. It is a flowchart for demonstrating the other example of the image display method by the image display apparatus of this invention. It is a flowchart for demonstrating the other example of the image display method by the image display apparatus of this invention. It is a block diagram which shows schematic structure of the FRC drive display circuit in the conventional liquid crystal display device. It is a figure for demonstrating the frame rate conversion process by the conventional FRC drive display circuit shown in FIG. It is a figure for demonstrating the interpolation frame production | generation process by a motion vector detection part and an interpolation frame production | generation part. It is a figure for demonstrating the example of the process which restrict | limits the output of a motion vector detection part to a vector evaluation calculation range.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,100 Frame rate conversion (FRC) part 11 Vector detection part 11a Luminance signal extraction part 11b Preprocessing filter 11c Motion detection frame memory 11d Initial vector memory 11e, 101 Motion vector detection part 11f Interpolation vector evaluation part 12 Frame generation part 12a Interpolation frame memory 12b, 102 Interpolation frame generation unit 12c Time base conversion frame memory 12d Time base conversion unit 12e, 12g Compensation strength variable unit 12f Interpolation vector memory 14 Motion amount determination unit 15 Control units 16, 25 Switching Unit 170 Vector 18, 104 Electrode driving unit 19, 103 Liquid crystal display panel 20, 26 Path 21 Decoding unit 22, 28 Memory 23, 27 Linear interpolation processing unit 24 Black level signal insertion processing unit 105 Motion vector 106 Interpolation vector Within 107 Frame

Claims (8)

Based on motion vector information detected in units of predetermined blocks between frames or fields of the input image signal, an image signal generated by performing motion compensation processing on the input image signal, and motion compensation processing on the input image signal by weighted addition at a ratio of the generated image signals of a predetermined without performing a interpolation image generating portion in which generates an interpolation image signal,
An image comprising rate conversion means having an image interpolation unit that converts the number of frames or fields of the input image signal by interpolating the interpolated image signal between frames or fields of the input image signal. A display device,
The image display apparatus determines whether a motion amount between frames or fields of the input image signal is larger than a predetermined value based on the number of blocks in one frame or one field in which the motion vector information exceeds a predetermined range. A determination means for determining whether each frame or field,
When the determination unit determines that the amount of motion between frames or fields of the input image signal is greater than a predetermined value, the interpolated image generation unit applies to an area including all pixels in the frame or field. The weighted addition ratio is changed so that the addition ratio of the image signal generated by applying motion compensation processing to the input image signal is lowered. The image display device according to claim 1,
When the amount of motion between frames or fields of the input image signal is greater than a predetermined value, the interpolation image generation unit sets the ratio of the image signal generated by performing motion compensation processing to the input image signal to 0,
If the motion amount between frames or between fields of the input image signal is smaller than a predetermined value, the image display, characterized in that the ratio of the image signal generated without applying the motion compensation process on the input image signal and the 0 apparatus. In the image display device according to claim 1 or 2,
The interpolated image generation unit uses an image signal that has been subjected to linear interpolation processing between frames or fields of the input image signal as an image signal generated without performing motion compensation processing on the input image signal. An image display device. In the image display device according to any one of claims 1 to 3,
The determination means is configured to input the input image signal for the current frame or field so as to prevent frequent switching between a frame or field determined to have a large amount of motion and a frame or field determined to have a small amount of motion. An image display device, wherein a predetermined value for determining whether or not a motion amount between frames or fields is greater than a predetermined value is changed in accordance with a motion amount determination result for the previous frame or field. In the image display device according to any one of claims 1 to 3,
When the determination means determines that the amount of motion between frames or fields of the input image signal is greater than a predetermined value, the determination means continuously outputs the determination result over a period of several frames thereafter. Display device. Based on motion vector information detected in units of predetermined blocks between frames or fields of the input image signal, an image signal generated by performing motion compensation processing on the input image signal, and motion compensation processing on the input image signal by weighted addition at a ratio of the generated image signals of a predetermined without performing a interpolation image generating step among which generates an interpolation image signal,
An image comprising a rate conversion step including an image interpolation step of converting the number of frames or fields of the input image signal by interpolating the interpolated image signal between frames or fields of the input image signal Display method,
Based on the number of blocks in one frame or one field in which the motion vector information exceeds a predetermined range, it is determined whether the amount of motion between frames or fields of the input image signal is larger than a predetermined value. A step of determining each time,
In the interpolated image generation step, when it is determined that the amount of motion between frames or fields of the input image signal is larger than a predetermined value, the input image signal is input to an area including all pixels in the frame or field. An image display method, wherein the weighted addition ratio is changed so that an addition ratio of an image signal generated by performing motion compensation processing on the image signal is lowered. Based on motion vector information detected in units of predetermined blocks between frames or fields of the input image signal, an image signal generated by performing motion compensation processing on the input image signal, and motion compensation processing on the input image signal by weighted addition at a ratio of the generated image signals of a predetermined without performing a interpolation image generating portion in which generates an interpolation image signal,
An image comprising rate conversion means having an image interpolation unit that converts the number of frames or fields of the input image signal by interpolating the interpolated image signal between frames or fields of the input image signal. A processing device comprising:
The interpolated image generation unit is configured such that a motion amount between frames or fields of the input image signal is greater than a predetermined value based on the number of blocks in one frame or one field in which the motion vector information exceeds a predetermined range. If it is determined by the determination means for determining whether the input image signal is large or not for each frame or field, the motion amount between the frames or fields of the input image signal is larger than a predetermined value, all the pixels in the frame or field are included. An image processing apparatus, wherein the weighted addition ratio is changed so that an addition ratio of an image signal generated by performing motion compensation processing on the input image signal is lowered for a region. Based on motion vector information detected in units of predetermined blocks between frames or fields of the input image signal, an image signal generated by performing motion compensation processing on the input image signal, and motion compensation processing on the input image signal by weighted addition at a ratio of the generated image signals of a predetermined without performing a interpolation image generating step among which generates an interpolation image signal,
An image comprising a rate conversion step including an image interpolation step of converting the number of frames or fields of the input image signal by interpolating the interpolated image signal between frames or fields of the input image signal A processing method,
Based on the number of blocks in one frame or one field in which the motion vector information exceeds a predetermined range, it is determined whether the amount of motion between frames or fields of the input image signal is larger than a predetermined value. A step of determining each time,
In the interpolated image generation step, when it is determined that the amount of motion between frames or fields of the input image signal is larger than a predetermined value, the input image signal is input to an area including all pixels in the frame or field. An image processing method, wherein the weighted addition ratio is changed so that an addition ratio of an image signal generated by performing motion compensation processing on the image signal is lowered.