Title:
PICTURE QUALITY COMPENSATING DEVICE
Document Type and Number:
Japanese Patent JPS63164765
Kind Code:
A
Abstract:
PURPOSE:To obtain a sharp picture without blooming by controlling the compensation quantity in an electric contour compensating means and a scanning speed modulation means reciprocally when the frequency band of the video signal is wide and the amplitude level is large. CONSTITUTION:A control signal generating circuit 23, based on frequency band information from a frequency detecting circuit 22 and amplitude information from an amplitude detection circuit 19, applies weighting and outputs a control signal (g). A voltage VG2 shown in one-dash chain lines in the signal (g) is fed to a gain control circuit 13 to apply the gain control so as to decrease the gain of the 2nd order differentiation signal when the frequency band of the video signal is at a high level and the amplitude of the video signal is high. Moreover, the voltage VG1 shown in solid lines in the signal (g) is fed to the gain control circuit 17 to apply gain control thereby increasing the gain of a 1st order differentiation signal when the frequency band of the video signal is high and the amplitude of the video signal is high. Thus, the effect of the scanning speed modulation in the display of high brightness and high definition is improved to obtain a picture whose contour is sufficiently sharp.
Inventors:
TSUJIHARA SUSUMU
Application Number:
JP31226986A
Publication Date:
July 08, 1988
Filing Date:
December 26, 1986
Export Citation:
Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
H04N5/208; H04N3/32; (IPC1-7): H04N3/32; H04N5/208
Attorney, Agent or Firm:
Tomoyuki Takimoto