Hitachi, Ltd.

Hitachi Video and Information System, Inc.

Other

Ryo Hasegawa

Hiroshi Aoki

Takaaki Matono

Takeshi Sakai

Yasutaka Tsuru

Naoya Oka

Masahiro Nako

Haruki Takata

Koichi Sudo

Tatsuo Nagata

Hirofumi Sakamoto

Daisuke Honda

Rikiya Asaoka

Hidenao Kubota

Junichi Ikoma

Katsunobu Kimura

Toshiaki Ohyama

Ryuichi Someya

Fumio Sogabe

Misako Nakagawa

A system provides an image displaying technique that provides stable high contrast even in an area having high brightness. Based on information about an average brightness level of a digital luminance signal, black-correction processing which decreases a brightness level by offsetting the brightness level to the minus side, and increase processing which increases a contrast gain within a dynamic range, are performed for an analog luminance signal or a digital luminance signal, enabling improvement in contrast even where brightness is intense.

Image displaying method, image displaying device, and contrast-adjusting circuit for use therewith

Disclosed is an image display technique for displaying a high-quality image by an image signal of appropriate color saturation. To this end, in the invention, color histogram information is detected from a color difference signal and average brightness information or brightness histogram information from a brightness signal. Based on the detected color histogram information and average brightness information or brightness histogram information, the demodulation axis of a color difference signal is adjusted, thereby controlling the color saturation (chroma) of an image. This enables display of an image having color intensity suited to the brightness and chroma of an image signal.

Image display apparatus, image signal processing circuit used therein, and method of controlling color saturation of image signal

With the aim of offering a video display technique by which stable and high contrast video images are reproduced, contrast adjusting circuitry is constructed. The contrast adjusting circuitry detects a maximum picture level (MPL) and an average picture level (APL) of analog -to-dialog converted luminance signals for a predetermined period, determines one of the predefined luminance regions within which the MPL falls and one of the predefined luminance regions within which the APL falls, and, based on the thus determined luminance regions of both MPL and APL, carries out a contrast adjustment of video images by changing the gain of luminance signals and color depth correction by changing the gain of color signals.

Contrast adjusting circuitry and video display apparatus using same

With the aim of offering a video display technique by which stable and high contrast video images are reproduced, contrast adjusting circuitry is constructed. The contrast adjusting circuitry detects a maximum picture level (MPL) and an average picture level (APL) of luminance signals for a predetermined period, determines one of the predefined luminance regions within which the MPL falls and one of the predefined luminance regions within which the APL falls, and, based on the thus determined luminance regions of both MPL and APL, carries out a contrast adjustment of video images by changing the gain of luminance signals and color depth correction by changing the gain of color signals.

An image processing apparatus is provided that performs more appropriate black stretch processing to display a high quality video. The image processing apparatus includes a luminance characteristics detection unit that analyzes a received video signal to detect a frequency of each of a plurality of luminance areas with a luminance at least equal to or lower than a predetermined luminance, a black stretch processing unit that performs black stretch processing for a luminance signal with a luminance equal to or lower than a predetermined luminance level, and a microcomputer that uses the frequency of each of the plurality of luminance areas, detected by the detection unit, to control the black stretch processing of the black stretch processing unit.

Image processing apparatus

Contrast adjusting circuitry and video display apparatus using the same

Image display method and apparatus are capable of displaying an input image signal in an optical condition on a display screen according to the brightness of the screen image. The image display apparatus for performing a specified process on an input image signal and displaying an image by the image signal on a display unit comprises a controller for adjusting a signal level detecting circuit for detecting brightness levels of an image by the input image signal by controlling the sharpness of an image by the image signal according to a detected signal level in such a way that as the detected signal level rises, the sharpness increases.

Image display method and apparatus

The present invention provides a technology for using an STB in conjunction with various display panels that comprise different types of display devices. The present invention comprises a display panel (), which includes a memory section () and a transmitter section (). The memory section () stores identification information (ID information), which includes the information about the type of a device constituting the display panel () and/or the specifications for the display panel. The transmitter section () transmits the ID information stored in the memory section () to a signal processing apparatus (). The signal processing apparatus () includes a control circuit (), which receives the ID information transmitted from the display panel (), determines the device type of the display panel and/or the specifications for the display panel from the received ID information, and exercises control in accordance with the determination result to change the operation of the signal processing apparatus.

Display system and display panel and signal processing apparatus for use with display system

A picture quality correction circuit is provided which performs contour correction by grasping features of an input video signal accurately. The correction circuit has a filter circuit for extracting contour components in an inputted video signal, a contour component nonlinear processor for changing amplitudes of the contour components extracted by the filter circuit, an adder for adding outputs of the contour component nonlinear processor and the input video signal, a histogram detection circuit for detecting a histogram of the contour components extracted by the filter circuit, and a control circuit for controlling contour emphasis quantities for the contour component nonlinear processor in accordance with the results of detection by the histogram detection circuit.

Video display apparatus having contour correction function

The present invention provides a technique for performing gamma correction processing when there are a plurality of characteristic areas, each of which is characterized by the high frequency in a luminance histogram to improve the impression of contrast. According to the present invention, a luminance characteristic detector () detects the luminance of an input image signal and a microcomputer () calculates an APL and a luminance histogram of an input image signal. A gamma correction circuit () performs the gamma correction processing in response to the luminosity of the input image signal by use of the result of the calculation carried out by the microcomputer (). Then, if there are a plurality of characteristic areas, each of which is characterized by the high frequency in the luminance histogram, a characteristic emphasis circuit () performs grayscale extension processing for the plurality of characteristic areas. This makes it possible to perform the most suitable processing in response to the input image signal so that the impression of contrast is improved.

Image display apparatus

An object of the present invention is to provide an image display technology with which high contrast can be stably obtained. In order to achieve the above object, the present invention changes the gain of a digital luminance signal by feeding back information on maximum and average luminance levels of the luminance signal, adjusts image contrast, and in accordance with the average luminance level detected from the feedback system, controls the illuminance of the backlight applied to a display unit. The control increases the illuminance of the backlight when the detected average luminance level is higher than the upper-limit value of a previously set reference range, and reduces the illuminance when the detected average luminance level is lower than the lower-limit value of the reference range.

Image display apparatus, display unit driver and image display method for the same

Embodiments of the invention provide a video display technique with which a stable video with a high contrast can be obtained according to brightness of a screen. In one embodiment, a video signal processing system for a video display apparatus which performs display on the basis of a video signal comprises a gain control module configured to provide a feedback signal based upon maximum luminance level information and average luminance level information of a luminance signal corresponding to the video signal, the feedback signal being used to control a gain of the luminance signal; and a correction module configured to apply a gamma correction based upon the average luminance level information to the video signal after the gain of the luminance signal has been controlled by the gain control module.

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Yokohama, Japan

Ryo Hasegawa