Title:
DIGITIZING METHOD FOR PICTURE SIGNAL
Document Type and Number:
Japanese Patent JPS6467087
Kind Code:
A
Abstract:
PURPOSE:To prevent the deterioration of a picture processing accuracy due to darkness by digitizing an analog picture signal constantly with constant accuracy without relating to the brightness of the picture for the picture photographed by an ITV camera. CONSTITUTION:In a voltage maximum value and minimum value detecting circuits 3, 4, a signal is detected only for a picture output period 25, consequently, voltage maximum and minimum value detecting signals 13, 14 are outputted to delay circuits 5, 6. The voltage maximum value and minimum value are detected for every horizontal synchronizing signal during the interval of a vertical synchronizing signal, namely, the period of one screen. At the last time of a vertical scanning period 27, the voltage of the brightest part in one screen is outputted as the voltage maximum value detecting signal 13 and the voltage value of the darkest part in the one screen is outputted as the voltage minimum value detecting signal 14. Then, since the maximum value and the minimum value of an input picture signal voltage before one vertical scanning period are defined to be the input voltage range of an analog/digital converter, when an input picture signal is dark, a difference between the maximum value and the minimum value is reduced. Thereby, a dark picture can be highly accurately digitized.
Inventors:
YASUMOTO MASAAKI
KIRII YUJI
KIRII YUJI
Application Number:
JP22209787A
Publication Date:
March 13, 1989
Filing Date:
September 07, 1987
Export Citation:
Assignee:
NACHI FUJIKOSHI CORP
International Classes:
G06T1/00; H04N19/85; H04N19/423; (IPC1-7): G06F15/64; H04N7/13
Domestic Patent References:
| JPS61102871A | 1986-05-21 |
Attorney, Agent or Firm:
Junji Kawachi