WO1999000975A1 - Method and device for reproducing images - Google Patents
Method and device for reproducing images Download PDFInfo
- Publication number
- WO1999000975A1 WO1999000975A1 PCT/NL1998/000375 NL9800375W WO9900975A1 WO 1999000975 A1 WO1999000975 A1 WO 1999000975A1 NL 9800375 W NL9800375 W NL 9800375W WO 9900975 A1 WO9900975 A1 WO 9900975A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- pixel
- image
- function
- brightness
- initial
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims description 25
- 238000001914 filtration Methods 0.000 claims abstract description 9
- 230000001419 dependent effect Effects 0.000 claims description 9
- 239000003086 colorant Substances 0.000 claims description 8
- 238000001514 detection method Methods 0.000 claims 2
- 230000006870 function Effects 0.000 description 16
- 239000010408 film Substances 0.000 description 8
- 230000035945 sensitivity Effects 0.000 description 5
- 238000002601 radiography Methods 0.000 description 4
- 239000011521 glass Substances 0.000 description 3
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- 238000000149 argon plasma sintering Methods 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 230000016776 visual perception Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/14—Picture signal circuitry for video frequency region
- H04N5/20—Circuitry for controlling amplitude response
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/30—Transforming light or analogous information into electric information
- H04N5/32—Transforming X-rays
Definitions
- the invention relates to a method for reproducing images comprising an area made up of pixels and having a brightness value for each pixel, which method comprises varying the brightness values of the pixels according to a function which is dependent on and not constant with time.
- the invention also relates to a method for reproducing images comprising an area made up of pixels and having a brightness value for each pixel, wherein each pixel may be composed per se of at least two different colours and wherein the intensity for at least one and at most all with the exception of one of the colours may also permanently be zero.
- Radiography The obtaining of medical X-ray images is referred to as radiography. Radiography is nowadays performed both by an analog procedure and by a digital procedure.
- analog radiography procedure a photographic film is exposed to the X-ray image to be reproduced, developed and subsequently reproduced by placing the developed film in a generally somewhat darkened room in front of a light box and then viewing it.
- digital manner of radiography the image is obtained electronically. It can then be reproduced on a viewing screen.
- viewing screens have the following contrast-reducing properties: light scattering between the phosphor layer and the glass window; reflection of the ambient light at the outer surface of the glass window.
- the contrast sensitivity of an observer in relation to an observed image depends on the depth of modulation with which said image is presented to an observer image by image.
- the contrast sensitivity can be increased by changing the image brightness from image to image, for instance by modulating the image brightness with a frequency between 5 and 50 Hz.
- the brightness of the reproduced image could also be increased, but that is not possible to an adequate extent due to technical limitations, such as maximum electron current and saturation of the phosphor.
- the light scattering in the thin film is also less than in the thick glass window of the viewing screen.
- the object of the invention is to improve the contrast observation of an image comprising an area made up of pixels, such as, for example, a medical X-ray image on a viewing screen.
- Patent Application 84.01605 a television image projected on a screen, a video monitor, a film for a screen, on which screen a television image is projected, an LCD monitor.
- the method according to the invention which method comprises varying the brightness value of the pixels is characterized in that the function is also dependent on the initial brightness with which at least the respective pixel would be reproduced if the function were not used and in that, for higher initial brightnesses, the ratio between the highest and the lowest value of the function is at least just as close or closer to one than for lower initial brightnesses.
- each pixel may be made up of at least two different colours
- the colour coordinates of each pixel are varied according to a function which is not constant with time and which is dependent on the initial brightness with which at least the respective pixel would be reproduced if the function were not used and in that, for higher initial brightnesses, the variation in colour coordinates is at most just as great or is smaller than for lower initial brightnesses.
- the image comprises an area made up of pixels and having a brightness value for each pixel.
- Viewing screen devices to which the invention can be applied often comprise, specifically, a so-called "look-up" table which determines the relationship between a signal presented to the viewing screen device and the signal which controls the image brightness on the screen, for example the intensity of the electron beam.
- a device in which the invention is used in this simple way is therefore characterized by at least two non-identical tables and means for changing from the one to the other "look-up" table during a picture return.
- a method according to the invention is characterized in that at least two different, spatially filtered variants of the original image are alternated.
- the reproduction system should therefore have at its disposal a larger memory from which the various filtered images can be retrieved.
- the increase in the contrast sensitivity depends both on the frequency and the depth of modulation of the modulated signal and is associated with the brightness to be reproduced.
- the first is the function which specifies the processing for the signal which determines or reproduces the brightness and/or the colour of the image on the viewing screen.
- the second is the function which specifies the order in which the images are reproduced which have not been processed or have been processed using the first function. Examples of the second function are: processed - not processed - processed - not processed etc., also to be described as yes/no/yes/no/yes/no... yes/no/no/yes/no/no/yes/no/no... yes/no/no/no/yes/no/no/no processed according to function 1/not processed/not processed according to function
- the function which specifies the processing can be, according to the above: another brightness, another colour, another spatial filtering.
- the depth of modulation can be made to increase with decreasing brightness and/or the modulation frequency can be chosen closer to that for optimum contrast observation.
- the second function it is advantageous to choose the period time as a whole multiple of the image interval, as in the examples reproduced above.
- image repetition frequency of 70 Hz which is standard per se, 35, 23.3, 17.5, 14, 11.6, 10, 9.1, 8.3 Hz etc. are then obtained as possible frequencies.
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP98931146A EP0992156A1 (en) | 1997-06-27 | 1998-06-29 | Method and device for reproducing images |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL1006420A NL1006420C2 (en) | 1997-06-27 | 1997-06-27 | Method and device for displaying images. |
NL1006420 | 1997-06-27 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1999000975A1 true WO1999000975A1 (en) | 1999-01-07 |
Family
ID=19765237
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/NL1998/000375 WO1999000975A1 (en) | 1997-06-27 | 1998-06-29 | Method and device for reproducing images |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0992156A1 (en) |
NL (1) | NL1006420C2 (en) |
WO (1) | WO1999000975A1 (en) |
Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4438495A (en) * | 1981-11-13 | 1984-03-20 | General Electric Company | Tomography window-level gamma functions |
US4891757A (en) * | 1986-04-14 | 1990-01-02 | Picker International, Inc. | Medical imaging system and method having gray scale mapping means for indicating image saturation regions |
EP0357842A1 (en) * | 1988-09-07 | 1990-03-14 | Agfa-Gevaert N.V. | Digital image processing taking into account the standard deviation |
US5101272A (en) * | 1988-05-25 | 1992-03-31 | Picker International, Inc. | Dual bandwidth/gain video preamplifier |
US5253281A (en) * | 1991-07-30 | 1993-10-12 | Siemens Aktiengesellschaft | X-ray diagnostics installation for subtraction angiography |
US5263099A (en) * | 1989-11-17 | 1993-11-16 | Picker International, Inc. | High speed window and level function modification for real time video processing |
US5345513A (en) * | 1991-03-30 | 1994-09-06 | Fujitsu Limited | Method and apparatus for processing image corresponding to radiographic pattern |
JPH07177431A (en) * | 1993-12-21 | 1995-07-14 | Mitsubishi Electric Corp | Video signal processor and x-ray camera |
US5609152A (en) * | 1991-11-27 | 1997-03-11 | Thermotrex Corporation | Prone position stereotactic mammography needle biopsy apparatus and method for using the same |
EP0779770A1 (en) * | 1995-12-14 | 1997-06-18 | General Electric Company | Adaptive X-ray brightness and display control for a medical imaging system |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5447153A (en) * | 1993-07-02 | 1995-09-05 | Eastman Kodak Company | Real-time window/leveling on a radiographic workstation |
IL106691A (en) * | 1993-08-13 | 1998-02-08 | Sophis View Tech Ltd | System and method for diagnosis of living tissue diseases |
EP0703541A1 (en) * | 1994-09-23 | 1996-03-27 | Vaisfeld, Sorin, Dr. | Apparatus and method for aiding diagnostic analysis of medical images, particularly dental X-ray-images |
-
1997
- 1997-06-27 NL NL1006420A patent/NL1006420C2/en not_active IP Right Cessation
-
1998
- 1998-06-29 WO PCT/NL1998/000375 patent/WO1999000975A1/en not_active Application Discontinuation
- 1998-06-29 EP EP98931146A patent/EP0992156A1/en not_active Withdrawn
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4438495A (en) * | 1981-11-13 | 1984-03-20 | General Electric Company | Tomography window-level gamma functions |
US4891757A (en) * | 1986-04-14 | 1990-01-02 | Picker International, Inc. | Medical imaging system and method having gray scale mapping means for indicating image saturation regions |
US5101272A (en) * | 1988-05-25 | 1992-03-31 | Picker International, Inc. | Dual bandwidth/gain video preamplifier |
EP0357842A1 (en) * | 1988-09-07 | 1990-03-14 | Agfa-Gevaert N.V. | Digital image processing taking into account the standard deviation |
US5263099A (en) * | 1989-11-17 | 1993-11-16 | Picker International, Inc. | High speed window and level function modification for real time video processing |
US5345513A (en) * | 1991-03-30 | 1994-09-06 | Fujitsu Limited | Method and apparatus for processing image corresponding to radiographic pattern |
US5253281A (en) * | 1991-07-30 | 1993-10-12 | Siemens Aktiengesellschaft | X-ray diagnostics installation for subtraction angiography |
US5609152A (en) * | 1991-11-27 | 1997-03-11 | Thermotrex Corporation | Prone position stereotactic mammography needle biopsy apparatus and method for using the same |
JPH07177431A (en) * | 1993-12-21 | 1995-07-14 | Mitsubishi Electric Corp | Video signal processor and x-ray camera |
EP0779770A1 (en) * | 1995-12-14 | 1997-06-18 | General Electric Company | Adaptive X-ray brightness and display control for a medical imaging system |
Non-Patent Citations (2)
Title |
---|
PATENT ABSTRACTS OF JAPAN vol. 95, no. 10 30 November 1995 (1995-11-30) * |
See also references of EP0992156A1 * |
Also Published As
Publication number | Publication date |
---|---|
NL1006420C2 (en) | 1998-12-29 |
EP0992156A1 (en) | 2000-04-12 |
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