Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Yoshio Seki

Atsushi Ishizu

Masaki Tokoi

Masahiro Yoshida

Katsuhisa Kitada

Tsuyoshi Maeda

Yoichiro Miki

Takayuki Kimoto

Susumu Tsujihara

Mitsuo Isobe

Ikunori Inoue

Hideaki Yamauchi

Tomohisa Tagami

Akihiro Kuwabara

A projectordetects a luminance distribution in an effective video period of an inputted video luminance signal, and a coefficient calculating circuitcalculates a correction coefficient Cto correct a gradation (FIG.A). Then, surrounding brightness is detected, and the correction coefficient Cis adjusted based on the surrounding brightness to obtain an adjusted correction coefficient C' (FIG.B). As shown in FIG.C, a luminance can be raised to Q according to a brightness signal even for a pixel of a lowest input luminance by adjusting the correction coefficient. Other correction coefficients in a range of 0 to 255 before adjustment are proportionally distributed to a range of 0 to 255-Q, and added with a correction coefficient Q. A luminance of each pixel which belongs to the effective video period of the video luminance signal is adjusted using the adjusted correction coefficient.

Image display and image displaying method for gradation correction

A noise reduction apparatus in accordance with the present invention is configured to reduce mosquito noise while retaining edges by calculating the maximum value Y of the difference values of adjacent pixels in an area of M&#xd7;N around a notice pixel by using a difference value calculator and a maximum value calculator, by controlling a pixel replacement device depending on Y and the difference value X from the notice pixel in the area of J&#xd7;K narrower than the area of M&#xd7;N, and by carrying out more intense smoothing depending on the magnitude of X with respect to Y, that is, when X is smaller than Y.

Noise reduction method, noise reducing apparatus, medium, medium and program

The invention includes an interpolation circuit for generating interpolation scanning lines by averaging adjacent scanning lines from an interlaced input video signal. Also included is a motion detecting circuit for detecting the amount of motion of the input video signal. The output signal of the interpolation circuit is connected to an amplitude control circuit controlled by the amount of motion from the motion detecting circuit. The input video signal terminal and the output terminal of the amplitude control circuit are connected to a converter circuit which performs time division multiplexing of the interlaced input video scanning lines and interpolation scanning lines by using a clock 2fH from a control signal input terminal. The clock has a frequency which is two times the horizontal scanning frequency. The motion detecting circuit detects the amount of motion and if the amount of motion is small, amplitude control of the interpolation scanning lines is not-performed. If the amount of motion is large, control is performed in the amplitude control circuit to provide an amplitude difference between the real scanning lines and the interpolation scanning lines.

Sequential scanning converter

Scanning lines are automatically shifted by using a test signal for detecting a screen display height, a detector which detects information of the screen display height from the test signal, a calculator which calculates a scanning-line shift amount, a moire correcting waveform generator which generates a voltage for shifting the scanning lines, and a deflecting device which deflects electron beams.

Moire reducing apparatus

A visual image signal processing apparatus includes: an overlaying unit for overlaying a brightness reference signal at a predetermined position in a fly-back period of an input visual image signal; a first clamping unit for clamping an output from the overlaying unit at a predetermined clamping voltage; a detecting unit for applying an output from the first clamping unit to a driving electrode of a cathode ray tube and for detecting a beam current flowing based on the brightness reference signal overlaid in the input visual image signal; and a second clamping unit for controlling the predetermined clamp voltage based on the beam current detected by the detecting unit.

Visual image signal processing apparatus using arithmetic operation on

A video signal conversion apparatus for converting high definition television signals band-width compressed by offset sub-sampling to a conventional standard television signal while removing aliasing interference caused by offset sub-sampling and using less memory capacity than is conventionally required is provided. The image of the sub-sampled signal is restored from the sampling points in the current field by an intra-field interpolation circuit, and the number of scan lines is reduced to the same number in the standard television signal format by a scan line number conversion circuit. Half of the pixels in the current field are then substituted into the signal for the one previous frame for inter-frame interpolation by a signal selector which alternately selects a signal from the scan line number conversion circuit and a signal from field memories, and a time-base operation for removing aliasing interference at the standard television signal rate is executed.

Video signal converting apparatus with reduced processing for aliasing

In a video signal processing apparatus for restoring a signal which has been bandwidth-compressed by offset sub-sampling after restoring an image from sample points of a same field of a sub-sampled signal, a first adder performs an inter-field averaging process from inter-field signals before or after three adjacent fields. A second adder performs an inter-frame averaging process from inter-frame signals. One field difference and one frame difference are detected from the three adjacent inter-field signals thereby switching an output signal of the first adder and an output signal of the second adder in accordance with the magnitudes of the differences thus detected. In this way, aliasing interferences accompanied with bandwidth compression can be detected. By selecting an optimum eliminating filter, aliasing interference due to interfield sub-sampling and aliasing interference due to inter-frame sub-sampling can be eliminated.

Video signal processing apparatus for reducing aliasing interference

A television signal converting apparatus receives a high definition television signal which is processed approximately linearly on the transmission and receiving sides and whose transmission only is processed non-linearly. A non-linear level correction circuit is provided, which collectively simultaneously carries out two kinds of non-linear processes, namely, a transmission inverse gamma correction and a CRT gamma correction, which are executed on the transmission side, thus precisely reproducing the signal level of a luminance signal by using a small-scale circuit.

HDTV to conventional TV signal converting apparatus with non-linear

A video signal converting apparatus includes: an interpolating circuit for interpolating a non-sampling point from sampling points in a field for restoring an HDTV band-compressed by offset sub-sampling; a first delay element for delaying the interpolated signal by one field period and a second delay element for delaying an output of the first delay element by one field; a median-value selector for selecting a median-value signal from signals in three adjacent fields from the input and output of the two delay elements, and an adder for averaging the output of the first delay element and an output of the median-value selector. Alternatively, the first and second delay elements maybe disposed before the interpolating circuit rather than after the interpolating circuit. Furthermore, a time-access conversion circuit maybe disposed either before the interpolating circuit or after the adder.

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Osaka, Japan

Yoshio Seki