Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Reexamination Certificate
1998-04-17
2001-03-27
Grant, II, Jerome (Department: 2724)
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
Reexamination Certificate
active
06208433
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image pick-up apparatus, and more particularly, to a camera type image pick-up apparatus for use in picking up pictures with light of fluorescent lamp in an ordinary room.
Conventionally, it is called “flicker” that quantity of light varies in response to the utility power frequency. An object illuminated by a light source with the flicker, such as fluorescent lamp, is often picked up by a camera having a linear image sensor. In such a case, a noise composed of a pattern of lateral stripes inevitably appears on the picked up image, when a period of driving the linear image sensor is nearly equal to that of flicker. A quality of the image is deteriorated by the noise of the pattern of lateral stripes.
A conventional image pick-up apparatus is disclosed, for example, in Japanese Unexamined Patent Publication 203286/1995 with a proposal for preventing the noise of the pattern of lateral stripes. In the conventional image pick-up apparatus disclosed in the Japanese Unexamined Patent Publication 203286/1995, as will later be described more in detail, a compensation is carried out by the use of a part of an image signal obtained from a camera by picking up an image of an actual object. It is therefore required that a reflectivity in a visual field extracting flicker components is kept constant. When an object such as a hand, an eraser, and an original copy, lies in the visual field extracting flicker components, image signals are subjected to deviation influenced by the obstacles. In the conventional image pick-up apparatus, such a deviation of image signals cannot be distinguished from that caused by flicker. As a result, the compensation cannot be correctly carried out in the conventional image pick-up apparatus.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an image pick-up apparatus capable of picking up an image of high quality, in which a flicker compensation can be correctly carried out without influence by the reflectivity of an object.
Other objects of the present invention will become clear as the description proceeds.
On describing the basic operation of the present invention, it is readily understood that an image pick-up apparatus is for use in picking up an image of an original copy on an one-dimensional image pick-up device, and for capturing a two-dimensional image by mechanically scanning in a direction perpendicular to said one-dimensional image pick-up device.
According to an aspect of the present invention, the image pick-up apparatus comprising: an optical guide means for receiving an ambiance light added to a portion of said one-dimensional image pick-up device, a flicker compensation means for eliminating flicker noise of said received light using a photoelectric conversion signal of the light obtained from said optical guide means, and a flicker signal area for receiving said light output from said optical guide means and an image signal area for imaging an image of the original copy being completely separated optically in said one-dimensional image pick-up device.
The optical guide means may be disposed at an end potion of a scanning start side of said one-dimensional image pick-up device.
The light incident portion of said optical guide means may be a diffuser.
A condenser may be provided at the light output portion of said optical guide means.
The optical guide means may be composed of a prism.
The prism and said one-dimensional image pick-up device may be spaced apart and the space may be enclosed by a shading plate.
The optical guide mean may be composed of an optical fiber.
The flicker compensation means may be composed of a sample-hold circuit and a first division circuit, in which said sample-hold circuit samples and holds the photoelectric conversion output of the light obtained from said optical guide means, while said first division circuit divides an output signal of said image pick-up device by the output signal of said sample-hold circuit.
The flicker compensation means may be composed of a sample-hold circuit, a second division circuit and a multiplication circuit, in which said sample-hold circuit samples and holds the photoelectric conversion output of the light obtained from said optical guide means, and said second division circuit divides the output signal of said sample-hold circuit by a predetermined constant, while said multiplication circuit multiplies an output signal of said image pick-up device by the output signal of said second division circuit.
The flicker compensation means may be composed of an A/D conversion means and an operation means, in which said A/D conversion means quantifies a video signal output from said one-dimensional photoelectric conversion device, while said operation means executes an operation with the value of said flicker signal area and the value of said image signal area.
REFERENCES:
patent: 4114030 (1978-09-01), Nojiri
patent: 4616266 (1986-10-01), Hennig
patent: 4698686 (1987-10-01), Endo
patent: 4752741 (1988-06-01), Kim
patent: 4992855 (1991-02-01), Takei
patent: 5045928 (1991-09-01), Takaiwa et al.
patent: 5146082 (1992-09-01), Abe
patent: 5153745 (1992-10-01), Brandkamp
patent: 5204741 (1993-04-01), Sakaguchi
patent: 5384595 (1995-01-01), Sakaguchi
patent: 5617139 (1997-04-01), Okino
patent: 5875042 (1999-02-01), Kashitani et al.
patent: 0320889A2 (1989-06-01), None
patent: 0062659 (1992-04-01), None
Fukano Tomoaki
Iwakawa Masato
Mutou Hiroyuki
Yamamoto Hajime
Grant II Jerome
NEC Corporation
Scully Scott Murphy & Presser
LandOfFree
Image pick-up apparatus capable of stable flicker... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image pick-up apparatus capable of stable flicker..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image pick-up apparatus capable of stable flicker... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2502293