Sharp Kabushiki Kaisha Corporation

Toshiyuki Fujine

Takashi Yoshii

Seiji Kohashikawa

Yoji Shiraya

Takashi Kanda

Tomoharu Noutoshi

Michiyuki Sugino

Masahiro Okui

Kazuyoshi Yoshiyama

Naoko Kondoh

Ryoji Sakurai

Toshiyuki Gotoh

Hideki Suzuki

Eishi Oda

Tomoo Nishigaki

Masaru Kadono

Yasushi Tetsuka

Yuji Kikuchi

Toshihiko Osada

Yuhya Sekiguchi

Yuhichiro Yamaguchi

Ryuichi Niiyama

Masahiko Akutsu

A video signal conversion device is realized in which even in a case where an HDR video signal following a first video format is converted into a HDR video signal following a second video format, supplementary information related to the HDR video signal following the original first video format is not lost. The video signal conversion device (or) includes: a conversion unit () that converts the high dynamic range video signal following the first video format into the high dynamic range video signal following the second video format; and an output unit () that outputs the supplementary information which is related to the high dynamic range video signal following the first video format.

Video signal conversion device, video signal conversion method, video signal conversion system, control program, and recording medium

Areas of a video signal that represent light emission are detected, the luminance levels at which said light emission areas are displayed are enhanced, emphasizing the areas, and the luminance stretching is controlled in accordance with the brightness of the surrounding environment, thereby increasing the resulting sense of brightness and improving the appearance of the video. A light emission detector counts pixels to generate a histogram of a prescribed feature quantity and identifies areas that fall within a prescribed range at the upper end of said histogram as being light emission areas. An area-active-control/luminance-stretching portion performs luminance stretching, increasing the luminance of a backlight portion and reducing the luminance of non-light emission areas of the video signal. The area-active-control/luminance-stretching portion switches between control curves, defining the relationship between the brightness-related index and the amount of stretching, in accordance with the brightness of the surroundings of the device.

Video display device and television receiving device with luminance stretching

The present invention makes possible video expressions with increased feeling of brightness and increased contrast feeling and to be able to prevent the feeling of brightness and the contrast feeling from becoming unnatural during execution of the multi-screen display. This video display device comprises: a control portion (a signal processing portion (); an area-active-control/luminance-stretch-portion ()) that controls a displaying portion () and a backlight portion (); and a display instruction detection portion () that detects display instructions of first and second input video signals. The control portion stretches and increases the luminance of the backlight portion (), and also controls a light emitting portion enhancement processing according to a result of the detection. In the light emitting portion enhancement processing, the display luminance of a light emitting portion is enhanced by producing a histogram by integrating number of pixels for a predetermined feature amount relating to the brightness of the input video signal, detecting an upper region of a predetermined range of the histogram as the light emitting portion, and reducing luminance of a video signal of non-light emitting portion except the light emitting portion of the input video signal.

Video display device and television receiving device

A light emission portion of a video signal is detected, and the display intensity of the light emission portion is enhanced for emphasis display. At this moment, the intensity stretch amount is controlled in accordance with a status of video black display, thereby increasing the feeling of brightness and hence improving the video quality. An area-active-control/luminance-stretching portion stretches and increases the intensity of a backlight portion on the basis of an index related to a brightness calculated, on the basis of a predetermined condition, from the input video signal, and lowers the video signal intensity of the non-light emission part excluding the light emission part. At this moment, the area-active-control/luminance-stretching portion changes, in accordance with a black display amount detected by a black detection portion, a control curve that defines the relationship between the index related to the brightness and the stretch amount.

Video display device and television receiving device including luminance stretching

A video display device increases a feeling of brightness and expresses a video with high contrast by detecting a part of a video signal that emits light, enhancing the display luminance of the light-emitting part, and displaying the part. A light emission detection portion () uses a prescribed feature quantity related to the brightness of an input video signal, predetermines the light emission quantity for the video signal on the basis of the relationship with the feature quantity, and detects the light emission quantity for each input video signal frame from the feature quantity. A backlight luminance stretch portion () stretches the light source luminance of the backlight according to the light emission quantity detected. A video signal luminance stretch portion () stretches the video signal according to the light emission quantity or the luminance distribution of the input video signal.

Video display device that stretches a video signal and a signal of the light source and television receiving device

When conducting video display with a wide color gamut display based on a video signal conforming to a standard (sRGB standard and the like) having a color reproduction range narrower than that of the wide color gamut display, the video processing circuitcorrects a color in a prescribed correction target color range partly including a red hue reference range as a center part in the color range of an equal hue from achromatic colors having the lowest saturation to red having the highest saturation in an expanded color reproduction range but not including red having the highest saturation in the expanded color reproduction range, so that the hue may change to a hue akin to yellow in the expanded color reproduction range. In so doing, the hue in the red hue reference range changes to red hue in the color reproduction range conforming to the sRBG standard. Furthermore, the hue change ratio into the hue akin to yellow becomes smaller in a color having a long distance from the red hue reference range in the expanded color reproduction range than a color having a distance close thereto. As a result, the wide color gamut display displayable of bright red having a high saturation can be fully utilized, while at the same time solving the problem of hue displacement in displaying red having an intermediate saturation.

Video display device

A histogram generation portion calculates a prescribed feature value of a pixel and the maximum feature value for the pixel, for each pixel of one frame of an input video signal. Then, the ratio of the feature value of the pixel to the maximum feature value is calculated for each pixel as an index of color brightness, and a histogram generated wherein the numbers of pixels are integrated by index value. An enhancement processing portion applies gain and carries out an enhancement for pixel values wherein the index in the histogram which the histogram generation portion generates is greater than or equal to a prescribed threshold. The feature value is treated as a luminosity (L*) which is defined with CIELAB chroma space. Additionally, the feature value may be data which has the maximum tone value among pixel RGB data, or may be a luminosity value (Y) of the pixel.

A liquid crystal display apparatus enables image display with optimum quality corresponding to the genre of an image to be displayed. The liquid crystal display apparatus controls the emission luminance of a backlight according to the APL of an image signal measured at an APL measuring portion. Upon emission luminance control, the display apparatus sets the follow performance of a change of the backlight emission luminance in following a change in a characteristic quantity of the image signal according to a genre so that the display image can be viewed without an odd feeling. Specifically, the APL of the image signal measured at the APL measuring portionis put into a filter, and the rate of a change in the APL on the time axis is controlled through weighted averaging to control the follow performance of the emission luminance control on the backlight. At this time, the genre of image to be displayed is determined, and a constant used for weighted averaging on the filteris changed according to the determined genre to optimize display quality for each genre.

Liquid crystal display apparatus

Disclosed is a display device in which high resolution representation is made by generating and displaying display data for each sub-pixel, and in which reduction in image quality is improved. The display device is provided with a display panel in which one pixel is constructed from sub-pixels of at least 4 colors. The display device generates the display data for each sub-pixel in accordance with an input image signal, and displays the display data on the display panel. Within the sub-pixels, high brightness sub-pixels which are the two sub-pixels having the highest brightness are arranged alternately with the other sub-pixels. Also, the area of each high brightness sub-pixel is smaller than that of the other sub-pixels. In a preferred example, the areas of the two sub-pixels having the highest brightness and the areas of the other two sub-pixels have area ratios in the following order: 1.0:1.0:1.6:1.6.

Display device and television receiver

Brightness expression without solid white pattern is enabled, and video expression with an improved black level is achieved. A distortion module () reduces the luminance of a backlight source according to the histogram of the video signal so that the contrast may be a predetermined target one. A configuration design unit () sets the gain according to the luminance level (BL) of the backlight source selected by the distortion module (). When setting the gain, the luminance level (BL) for reference of the backlight source preset according to the video feature value is referenced. If the video feature value meets a predetermined condition, the input video signal is always amplified with the gain. If not, depending on the relation between the BLand the BL, the input video signal is amplified or not.

Video display apparatus for adjusting the degree of amplification of the input image according to image characteristics

A liquid crystal display device in which a frame of the image signal to be displayed is written into a liquid crystal display panel while a backlight is activated intermittently within one frame period so as to prevent blur injury arising when displaying motion pictures includes: sections and for variably controlling the illumination duration of the backlight based on the detected type of the image content to be displayed. This configuration makes it possible to appropriately control the image quality degradation caused by blur injury, stroboscopic effect and flickering, hence realize total image quality improvement.

Liquid crystal display device

The present invention provides a display device capable of realizing an appropriate screen display luminance in accordance with a video feature quantity and brightness around and sufficiently reducing power consumption. A liquid crystal display apparatus () includes: a liquid crystal panel () for displaying a video by an input video signal; a backlight unit () as a light source for irradiating the liquid crystal panel (); and a brightness sensor () for detecting the brightness around the liquid crystal display apparatus (). According to the brightness detected by the brightness sensor (), luminance conversion characteristic defining the light emission luminance of the backlight for the feature quantity (such as APL) of the input video signal is changed. Here, the luminance conversion characteristic is changed so that the light emission luminance is reduced as the brightness around the liquid crystal display apparatus becomes darker and the position of the characteristic modification point as the point where the slope of the luminance conversion characteristic is changed is shifted in the direction of the feature quantity change. According to the obtained luminance conversion characteristic, the light emission luminance of the backlight is controlled.

In general, when a user views an image displayed on a display apparatus, visual environments, such as ambient brightness, a distance from the user to the display apparatus and so on, may disadvantageously cause the image displayed on the display apparatus to become difficult to view. Moreover, it is complicated and troublesome for the user to enter information of ambient light amount and others when setting a picture quality. An image display apparatus holds both question constituent information related to visual environments and choice information serving as answers to questions constituted by the question constituent information, and further holds a plurality of picture quality control rules suitable for visual environments assumed in accordance with the choice information serving as the answers. When sensing a power-up, the image display apparatus outputs the questions; acquires result information that is choices serving as answers from the user to those questions and that is used to acquire the picture quality control rules; and controls the picture quality in accordance with the picture quality control rules acquired in accordance with the result information.

Image display apparatus

A video with a display definition most suitable for the type of the video content to be displayed can be displayed. A liquid crystal display apparatus controls the luminance of the backlight light source according to the APL of the video signal measured by an APL measuring portion (). The range of the video signal the APL of which is measured can be determined by, e.g., the luminance level of the video signal or by the genre information included in the inputted video signal or the OSD display information used when the liquid crystal apparatus () performs OSD display. The drawing shows the state that the upper and lower non-video areas are removed and an effective video area is determined. With this, the additional information displayed when the video signal is of a specific genre and the OSD-displayed additional information can be excluded, and the luminance of the backlight light source can be controlled to realize a display definition most suitable for the video signal.

A liquid crystal display has an LCD controller, a microcomputer, and a storage section. The LCD controller is capable of setting up an image display period for performing display based on input image data and a black display period for performing display based on black display data, within one field period. The microcomputer switches the mode of the LCD controller between an impulse-drive mode having the image display period and the black display period within the one field period, and a hold drive mode having only the image display period. The storage section stores sets of reference gradation voltage data that are previously specified. A reference gradation voltage, which is generated at a reference gradation voltage generation section and used for driving the liquid crystal display panel, is variable according to the mode. Thus, it is possible to realize the liquid crystal display that can suppress changes in gamma characteristics so as to prevent deterioration of display quality even when the mode is switched.

Growing community of inventors

Osaka, Japan

Toshiyuki Fujine