Surgery – Endoscope – Having imaging and illumination means
Reexamination Certificate
1999-03-08
2001-07-03
Mulcahy, John (Department: 3739)
Surgery
Endoscope
Having imaging and illumination means
C600S160000, C600S180000, C600S181000, C248S068100
Reexamination Certificate
active
06254531
ABSTRACT:
BACKGROUND OF THE INVENTION
This application claims the priority of Japanese Patent Application Nos. 10-78351 and 10-78352 filed on Mar. 10, 1998 which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an electronic-endoscope controlling the quantity of light, and in particular, to the contents of light-quantity control for compensating for the lack of light quantity caused by the setting of a shielding period using an electronic endoscope executing an all-pixel reading system that uses the shielding period to read out all pixels accumulated in an image pickup device.
2. Description of the Prior Art
In an electronic endoscope apparatus, for example, CCD (Charge Coupled Device) is used as a solid image-pickup device, and this CCD is structured so as to obtain an image signal (video signal) by reading out charge accumulated in units of pixels by a photoelectric conversion device. In a simultaneous type electronic endoscope apparatus for example, color filters are arranged in units of pixels on the top surface of the forgoing CCD to thereby obtain a color image.
FIG. 9
shows an arrangement state for the forgoing color filters, and Mg (magenta) and Cy (cyan) pixels are arranged on an even line for example, andG (green) andYe (yellow) pixels are arranged on an odd line on a picked-up surface of CCD
1
as shown. In this CCD
1
, accumulated charge (pixel signal) in units of pixels is to be obtained through these color filters.
According to a conventional color difference line sequential mix reading (pixel mix reading) system, accumulated charges of pixels on the upper and lower lines are added and mixed to be read out. For example, during the first exposure, video signals of such odd field as a mixed signal of 0-line and 1-line, a mixed signal of 2-line and 3-line, . . . are read out, and during the second exposure, video signals of such even field as a mixed signals of 1-line and 2-line, a mixed signal of 3-line and 4-line, . . . are read out. Therefore, two lines of mixed signals of CCD
1
become one line of signals of field image, and one odd or even field of data are to be obtained by one exposure.
FIG. 10
shows an operation of signals read out from the foregoing CCD
1
, and in an electronic endoscope apparatus, an odd field and an even field are formed on the basis of the O (Odd)/E (Even) signal (field signal) for each {fraction (1/60)} second (vertical synchronizing period) as shown in FIG.
10
(A). Therefore, as shown in FIG.
10
(B), signals are accumulated in accumulation (exposure) time T of an electronic shutter during the forgoing period of {fraction (1/60)} second, and the accumulation mixed signal is read out during the next {fraction (1/60)} second period. As a result, as shown in FIG.
10
(C), an odd field signal, and an even field signal are to be obtained, and for example, the (n−1)th odd field signal becomes mixed signals of (0+1) line, (2+3) line, (4+5) line . . . which are shown on the left of
FIG. 6
, and the n-th even field signal becomes mixed signals of (1+2) line, (3+4) line, . . . which are shown on the right of FIG.
9
.
These odd field signals and even field signals are interlace scanned to be formed as a one-frame image, and this image is displayed as a moving image on a monitor. Also, in the endoscope apparatus, a freeze switch is arranged in the operating unit, and when this freeze switch is depressed, a still image at the time is formed and displayed.
BRIEF SUMMARY OF THE INVENTION
Object of the Invention
In the foregoing simultaneous type electronic endoscope apparatus, however, there is a time lag of {fraction (1/60)} second between those odd field image and even field image which are used to form the one-frame image as shown in the foregoing FIG.
10
(C), and if there is a shake of the endoscope itself, a movement of the object to be observed or the like during this period of time, there is the problem that the image quality (resolution, color shift, etc.) will be deteriorated when the still image is displayed.
Thus, the applicant sets a predetermined light shielding period and uses an all-pixel reading system for reading all pixels out from data obtained during one exposure using this period. However, due to a delay in a mechanical (gear) response from, for example, a light shielding plate that sets the light shielding period, the exposure may be insufficient during the period of time required to read out all pixels. That is, complete light shielding conditions are required during the light shielding period required to read out data, so the light shielding plate is activated slightly before the beginning of the light shielding period in view of its response time. This response operation (the operation performed until complete light shielding is achieved) may cause lack of light quantity.
The present invention has been achieved in the light of this problem, and its object is to provide an electronic-endoscope light-quantity controlling apparatus that can appropriately compensate for the lack of light quantity caused by delayed responses from a light shielding mechanism, using an electronic endoscope adapted to form a high-quality image using the all-pixel reading system.
Summary of the Invention
In order to achieve this object, an electronic endoscope apparatus controlling the quantity of light according to this invention comprises a light source; an outgoing light quantity varying means for variably adjusting the quantity of outgoing light from the light source based on a predetermined control value; a shielding means for intercepting light from the light source and setting a shielding period for an all-pixel reading system; a signal processing circuit executing the all-pixel reading system that uses the shielding period to read out signals for all-pixels accumulated in an image pickup device during a single exposure; a storage means for storing characteristic data between the control value and the quantity of outgoing light; and a light quantity controlling means for controlling the outgoing light quantity adjusting means based on the characteristic data stored in the storage means to adjust the quantity of outgoing light from the light source, thereby compensating for the lack of light quantity caused by a delayed response from the shielding means for a shielding operation.
Another phase of the invention is characterized in that the outgoing light quantity varying means comprises a lamp driving means varies a lighting voltage for a light source lamp, in that the storage means stores the characteristic data between the lighting voltage for the light source lamp and the quantity of outgoing light, and in that the light quantity controlling means varies the lighting voltage for the light source lamp based on the characteristic data to adjust the quantity of outgoing light from the light source, thereby compensating for the lack of light quantity caused by a delayed response from the shielding means for a shielding operation. The characteristic data for the lamp include data for lamp voltage with give the necessary and sufficient quantity of outgoing light for the period in which all the picture elements are to be read.
Yet another phase of the invention is characterized in that the outgoing light quantity varying means comprises a diaphragm for adjusting the quantity of outgoing light from the light source lamp, in that the storage means stores the characteristic data between the diaphragm value of a diaphragm and the quantity of outgoing light, and in that the light quantity controlling means varies the numerical aperture of the diaphragm based on the characteristic data stored in the storage means to adjust the quantity of outgoing light from the light source, thereby compensating for the lack of light quantity caused by a delayed response from the shielding means for a shielding operation.
In each of these aspects of the invention, a light quantity sensor for detecting the quantity of outgoing light from the light source can be provided to store in the storage mean
Higuchi Mitsuru
Takeuchi Shinji
Yamanaka Kazuhiro
Fuji Photo Optical Co., Ltd.
Mulcahy John
Snider Ronald R.
Snider & Associates
LandOfFree
Electronic-endoscope light quantity controlling apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electronic-endoscope light quantity controlling apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electronic-endoscope light quantity controlling apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2541501