Title:
ASPECT RATIO DISCRIMINATION CIRCUIT AND VIDEO MONITOR DEVICE
Document Type and Number:
Japanese Patent JP3575153
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To prevent the malfunction of laterally long image discrimination.
SOLUTION: The average luminance of video signals forming the upper and lower sections (black band sections) in the image of inputted video signals is found by an upper/lower average luminance operating part 9b, and the difference between the average luminance calculated here and the luminance of video signals corresponding to the black zone of image is calculated by an upper/lower luminance difference operating part 9c. Further, whether the ratio of area, in which this luminance difference is more than a prescribed level, is higher than a prescribed value or not is discriminated by a big luminance difference detecting part 9d and when it is discriminated the ratio of the area having luminance difference more than the prescribed level is higher than the prescribed value, it is judged that the video signal of 4:3 is inputted to a laterally long image discriminating part 9a. Besides, luminance difference between the average luminance and the luminance of video signals forming the central part of image is calculated by a central part luminance difference operating part 9e and whether the ratio of area, in which this luminance difference is less than a prescribed level, is higher than a prescribed value or not is discriminated by a small luminance difference detecting part 9f. When it is judged the luminance difference is less than a prescribed ratio, the discriminating operation of the laterally long image discriminating part 9a is stopped.
Inventors:
Yutaka Yamagata
Kenji Watanabe
Kenji Watanabe
Application Number:
JP2304796A
Publication Date:
October 13, 2004
Filing Date:
January 17, 1996
Export Citation:
Assignee:
ソニー株式会社
International Classes:
H04N5/46; (IPC1-7): H04N5/46
Domestic Patent References:
| JP7170425A |
Attorney, Agent or Firm:
Atsuo Waki
Yasuo Asami
Yasuo Asami