Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1997-11-24
2000-06-20
Allen, Stephone B.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
250586, 356236, G01J 142
Patent
active
06078041&
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a pixel density detector. To be more specific, it relates to a pixel density detector capable of detecting the density up to the limit of visibility of human eyes.
BACKGROUND ART
Various records of medical examination and consultation are daily produced in large volumes in medical organizations. Especially, an increase in the volume of medical pictures due to development and diffusion of image diagnostic equipment is posing a problem about how to preserve such medical pictures. Under such circumstances, the Ministry of Health and Welfare issued a circular notice to the effect that preservation of x-ray photograph, CT pictures, etc. may be made in the form of electronic media such as optical disc, magnetic disc, etc. in place of preservation of the original pictures.
With such changes in the medical environments, it is becoming necessary to accurately measure variable-density pictures of large surface area such as light transmission type X-ray photograph of chest for medical use, etc. up to the limit of visibility of human eyes and then decompose its density in pixels to store and reproduce it in numerical values.
By the way, methods and apparatuses for detecting the density of variable-density pictures currently known generally include the following:
The first method and apparatus is one which is designed to use, as light source, a uniform-plane light source "a" as shown in FIG. 5, condense the light from this light source "a" by a convex lens "b" after transmission through a film "f", and then detect the density by means of a plane CCD sensor "m". In FIG. 5, dotted lines indicate optical paths. The same is true with FIG. 6 to FIG. 10 that follow.
The second method and apparatus is one which is designed to use, as light source, a uniform-plane light source "a" as shown in FIG. 6, condense the light from this light source "a" by a cylindrical lens "c" after transmission through a film "f", and detect the density by means of a line CCD sensor "n".
The third method and apparatus is one which is designed to use, as light source, a line-scan light source "d" as shown in FIG. 7, condense the light from this light source "d" by a glass fiber bundle "g" after transmission through a film "f", and detect the density by means of a PIN photo diode "p". In FIG. 7, the arrow mark indicates the direction of scanning. The same is true with FIG. 8 to FIG. 10 that follow.
The fourth method and apparatus is one which is designed to use, as light source, a line-scan light source "d" as shown in FIG. 8, condense the light from this light source "d" on an integrating sphere "i" after transmission through a film "f", and detect the density by means of a PIN photo diode "p".
The fifth method and apparatus is one which is designed to use, as light source, a line-scan light source "d" as shown in FIG. 9, condense the light from this light source "d" by a glass fiber bundle "g" after transmission through a film "f", and detect the density by means of a PMT (photomultiplier tube) "t".
The sixth method and apparatus is one which is designed to use, as light source, a line-scan light source "d" as shown in FIG. 10, condense the light from this light source "d" on an integrating sphere "i" after transmission through a film "f", and detect the density by means of a PMT (photomultiplier tube) "t".
In addition to the above, there are also those which use LED or EL as light source.
However, said respective methods and apparatuses have the following problems:
For example, for digitizing an X-ray photograph of chest, a picture element resolution (positional resolution) of 4444.times.5398 pixels is required, but no plane CCD sensor "m" used for such a large surface area is put into practical use at present because of a variety of problems. For that reason, the first method and apparatus causes a problem not to detect density on the object X-ray photograph of chest, etc.
Moreover, while, as line CCD sensor "n", those of 1024, 2048 and 4096 pixels are developed currently, their resolution is l
REFERENCES:
patent: 4321630 (1982-03-01), Kramer
patent: 4629890 (1986-12-01), Goto et al.
patent: 5190163 (1993-03-01), Anzai et al.
patent: 5241459 (1993-08-01), Kaplan et al.
patent: 5332904 (1994-07-01), Cannon
patent: 5598008 (1997-01-01), Livoni
patent: 5650843 (1997-07-01), Moberg et al.
Karita Masakazu
Kotani Haruo
Allen Stephone B.
Nishimoto Sangyo Co., Ltd.
LandOfFree
Integrating cylindrical pixel density detector does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Integrating cylindrical pixel density detector, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Integrating cylindrical pixel density detector will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1855202