Critical technologies for electronic still imaging systems
`Critical technologies for electronic still imaging systems
`Michael Kriss, Ken Parulski, David Lewis
`Michael Kriss, Ken Parulski, David Lewis
`Eastman Kodak Company, Rochester, New York 14650
`Eastman Kodak Company, Rochester, New York 14650
`
`ABSTRACT
`ABSTRACT
`
`Electronic still camera systems are now in the consumer market place. The hard copy image quality of these systems
`Electronic still camera systems are now in the consumer market place. The hard copy image quality of' these systems
`is poor in comparison with the ever improving photographic film systems. However, the rate at which solid state
`is poor in comparison with the ever improving photographic film systems. However, the rate at which solid state
`image sensor technology, signal processing technology, mass storage technology, and non-photographic hard copy
`image sensor technology, signal processing technology, mass storage technology, and non -photographic hard copy
`technology are advancing indicates that these electronic still camera imaging systems will someday find a place
`technology are advancing indicates that these electronic still camera imaging systems will someday find a place
`alongside traditional photographic systems. The current and future status of these critical technologies is the
`alongside traditional photographic systems. The current and future status of these critical technologies is the
`subject of this paper.
`subject of this paper.
`
`1. INTRODUCTION
`1. INTRODUCTION
`On January 6, 1839, the Academie des Science in Paris announced that Louis Jacques Mande Daguerre had
`On January 6, 1839, the Academic des Science in Paris announced that Louis Jacques Mande Daguerre had
`"discovered a method to fix the images which were represented at the back of a camera obscura; ... ".1 Since that
`Since that
`"discovered a method to fix the images which were represented at the back of a camera obscura; ....
`eventful day photographic images have dominated how mankind has recorded history from world wars to family
`eventful day photographic images have dominated how mankind has recorded history from world wars to family
`outings and documented new discoveries ranging from the exploration of the atom and the tombs of ancient Egypt to
`outings and documented new discoveries ranging from the exploration of the atom and the tombs of ancient Egypt to
`the natural habitats of the rain forests, jungles, and deserts around the world. Before World War II there were no
`the natural habitats of the rain forests, jungles, and deserts around the world. Before World War II there were no
`serious challenges to the photographic method of image recording, but the commercial development of color
`serious challenges to the photographic method of image recording, but the commercial development of color
`television in the 1950's and the subsequent development of high quality magnetic recording and VLSI semi-conduc(cid:173)
`television in the 1950's and the subsequent development of high quality magnetic recording and VLSI semi-conduc-
`tor technology in the 1970's and 1980's has brought electronic image recording to the consumer in the form of home
`tor technology in the 1970's and 1980's has brought electronic image recording to the consumer in the form of home
`video systems. The new 8 mm video camcorders have replaced the Super 8 film systems as the choice for recording-
`video systems. The new 8 mm video camcorders have replaced the Super 8 film systems as the choice for recording
`family events and travel. In the commercial area, Electronic News Gathering, ENG, has replaced 16 mm film for
`family events and travel. In the commercial area, Electronic News Gathering, ENG, has replaced 16 mm film for
`television news broadcasting. Attempts are being made to use High Definition Television Systems ( HDTV) as a
`television news broadcasting. Attempts are being made to use High Definition Television Systems ( HDTV) as a
`replacement for film in the motion picture industry. While HDTV systems have not replaced film for motion picture
`replacement for film in the motion picture industry. While HDTV systems have not replaced film for motion picture
`production, the introduction of the BETA and VHS VCR systems and the Laser Disc systems have brought film
`production, the introduction of the BETA and VHS VCR systems and the Laser Disc systems have brought film
`originated movies into the homes of millions.
`originated movies into the homes of millions.
`
`During the same time span, conventional silver halide-based still photography has had strong, continuous growth.
`During the same time span, conventional silver halide -based still photography has had strong, continuous growth.
`This growth has been spurred by improvements in film, cameras and ease of processing. Today a consumer can spend
`This growth has been spurred by improvements in film, cameras and ease of processing. Today a consumer can spend
`less than $100 for a high quality 35 mm camera with autofocus, automatic exposure control, automatic film advance,
`less than $100 for a high quality 35 mm camera with autofocus, automatic exposure control, automatic film advance,
`automatic film speed indexing, and built-in electronic flash. The resulting images are of very high quality. But while
`automatic film speed indexing, and built -in electronic flash. The resulting images are of very high quality. But while
`conventional photography continues to enjoy strong growth there is another electronic imaging system appearing on
`conventional photography continues to enjoy strong growth there is another electronic imaging system appearing on
`the horizon, one that may someday share the consumer market with the film-based systems of today. The electronic
`the horizon, one that may someday share the consumer market with the film -based systems of today. The electronic
`still camera, ESC, is a commercial reality today, and it and the technologies that make it possible are the subject of
`still camera, ESC, is a commercial reality today, and it and the technologies that make it possible are the subject of'
`this paper.
`this paper.
`
`1.1
`1.1
`
`Electronic still camera system concept
`Electronic still camera system concept
`
`Figure 1 shows a conceptual ESC system that could be assembled from currently available products. The system and
`Figure 1 shows a conceptual ESC system that could be assembled from currently available products. The system and
`camera is built around the Still Video Floppy, SVF, which records the image as an analog video signal.2 Figure 2
`Figure 2
`camera is built around the Still Video Floppy, SVF, which records the image as an analog video signal.
`shows the original SVF standard along with the new High-Band standard. In both cases the camera records 50 single
`shows the original SVF standard along with the new High -Band standard. In both cases the camera records 50 single
`field images or 25 full frame images; a video frame is made up of two interlaced fields. In the case of the High-Band
`field images or 25 full frame images; a video frame is made up of two interlaced fields. In the case of the High -Band
`standard, the images are recorded using a higher carrier frequency thus providing more bandwidth for each scan line
`standard, the images are recorded using a higher carrier frequency thus providing more bandwidth for each scan line
`and yielding greater horizontal resolution; the vertical resolution remains the same- 242 lines for the field format
`and yielding greater horizontal resolution; the vertical resolution remains the same- 242 lines for the field format
`and 484 lines for the frame format.
`and 484 lines for the frame format.
`The player/recorder converts the SVF analog signal into a form suitable for display on a conventional television set or
`The player /recorder converts the SVF analog signal into a form suitable for display on a conventional television set or
`monitor and also allows one to capture images from broadcast television or from VCR/s and record them on the SVF
`monitor and also allows one to capture images from broadcast television or from VCR's and record them on the SVF
`disks. By using an image transceiver with a modem and public or private telephone communication systems one can
`disks. By using an image transceiver with a modem and public or private telephone communication systems one can
`send images anywhere in the world. Hard copy can be obtained from images stored on the SVF disks. The prints can
`send images anywhere in the world. Hard copy can be obtained from images stored on the SVF disks. The prints can
`be made from any number of print engines including thermal printers, electrophotographic printers, ink jet printers,
`be made from any number of print engines including thermal printers, electrophotographic printers, ink jet printers,
`and raster printers exposing conventional or instant photographic materials.
`and raster printers exposing conventional or instant photographic materials.
`
`SPIEVol. 1082 Applications of Electronic Imaging (1989) / 157
`SPIE Vol. 1082 Applications of Electronic Imaging (1989) / 157
`
`LG 1015
`
`1
`
`

`

`Still Video System
`Still Video System
`
`Home Film to
`SVF Unit
`
`Home Transfer Unit
`
`Film
`
`Video Monitor
`
`Electronic Camera
`Electronic Camera
`
`Still Video Player /Recorder
`Floppy
`(single or multi -disk)
`
`Image
`I Transceiver
`* Transceivor
`
`Amplitude
`Amplitude
`
`Telephone
`
`Video Monitor +
`
`TV-Photo Lab System
`TV -Photo Lab System
`
`Hard C°W Device
`Hard Copy Device
`
`Image Transceiver
`Image Transceiver
`
`FM Color difference
`FM Color difference
`Signal v
`Signal
`
`FM Luminance Signal, Y
`FM Luminance Signal, Y
`
`H Normal
`
`I
`Normal
`Frequency - —
`1 Frequency
`I
`High Band
`,
`Deviation 1
`Deviation
`High Band
`r— Frequency— A
`Frequency
`'
`Deviation
`1
`Deviation
`
`[ X.
`
`f,, 2
`
`6
`4
`5
`Frequency (MHz)
`Frequency (MHz)
`f 1 ; R-Y Color difference, 1.2 MHz Center frequency
`ft; R -Y Color difference, 1.2 MHz Center frequency
`f2; B-Y Color difference, 1.3 MHz Center frequency
`f2; B -Y Color difference, 1.3 MHz Center frequency
`
`7
`
`8
`
`9
`
`Figure 1. Conceptual diagram of a possible still
`Figure 1. Conceptual diagram of a possible still
`video system based on the still video floppy, SVF,
`video system based on the still video floppy, SVF,
`standard.
`standard.
`
`Figure 2. The image encoding standard for SVF
`Figure 2. The image encoding standard for SVF
`systems.
`systems.
`
`An additional feature of the system is that a scanner can be used to convert existing images on negatives, transparen(cid:173)
`An additional feature of the system is that a scanner can be used to convert existing images on negatives, transparen-
`cies, or paper into electronic signals for recording on the SVF disks. Image scanners/recorders can be installed either
`cies, or paper into electronic signals for recording on the SVF disks. Image scanners /recorders can be installed either
`at photofinishers or in the home. Such a system provides complete flexibility to the consumer.
`at photofinishers or in the home. Such a system provides complete flexibility to the consumer.
`Figure 3 provides a more detailed look at the important parts of a ESC system; the system shown is just an
`Figure 3 provides a more detailed look at the important parts of a ESC system; the system shown is just an
`abstraction of an ESC system and does not represent any particular product. One key aspect of such a system is that
`abstraction of an ESC system and does not represent any particular product. One key aspect of such a system is that
`film-based images that are scanned into it can make use of the same system hardware and software that is used to
`film -based images that are scanned into it can make use of the same system hardware and software that is used to
`transform the electronically captured image into a final hard copy print, soft display, or transmitted image.
`transform the electronically captured image into a final hard copy print, soft display, or transmitted image.
`In what follows, detailed discussions will be presented on the key ESC technologies: the solid state sensors that
`In what follows, detailed discussions will be presented on the key ESC technologies: the solid state sensors that
`record the image, the in-camera signal processing that is required, the recording technology that stores the images,
`record the image, the in- camera signal processing that is required, the recording technology that stores the images,
`and the hard copy technology that produces prints. In far less detail, the technologies that deal with data compres(cid:173)
`and the hard copy technology that produces prints. In far less detail, the technologies that deal with data compres-
`sion and image manipulation will be discussed; the brevity of the discussions are not meant to imply that the
`sion and image manipulation will be discussed; the brevity of the discussions are not meant to imply that the
`technologies are not important, but that the detail required to fully understand the technologies falls beyond the
`technologies are not important, but that the detail required to fully understand the technologies falls beyond the
`scope of this paper.
`scope of this paper.
`As a final and very significant part of understanding an ESC system, the impact of international standards will be
`As a final and very significant part of understanding an ESC system, the impact of international standards will be
`discussed. One of the key issues is the need for a world-wide, digital, non-broadcast television-based family of
`discussed. One of the key issues is the need for a world -wide, digital, non -broadcast television -based family of
`standards for future ESC systems.
`standards for future ESC systems.
`In most of what follows, the emphasis will be directed toward systems that use hard copy output rather than soft
`In most of what follows, the emphasis will be directed toward systems that use hard copy output rather than soft
`display. The reason for this bias is based on the authors' feelings that an ESC system must produce hard copy images
`display. The reason for this bias is based on the authors' feelings that an ESC system must produce hard copy images
`equivalent in quality to photographic prints. Many ESC images will be viewed via electronic displays, but current
`equivalent in quality to photographic prints. Many ESC images will be viewed via electronic displays, but current
`electronic display technology does not equal the photographic print or projected transparency for overall quality.
`electronic display technology does not equal the photographic print or projected transparency for overall quality.
`Our crystal ball does not show us what display technology will hold sway in the future, so we, along with you, will have
`Our crystal ball does not show us what display technology will hold sway in the future, so we, along with you, will have
`to watch the drama unfold before us.
`to watch the drama unfold before us.
`1.2 Milestones in ESC systems 3,4,5
`1.2 Milestones in ESC systems 3>4'5
`Table 1 shows a complete list of ESCs that have been developed to date. A few of them rate special recognition from
`Table 1 shows a complete list of ESCs that have been developed to date. A few of them rate special recognition from
`In 1981 Sony demonstrated its Mavica color still camera and viewer, Mavipak
`In 1981 Sony demonstrated its Mavica color still camera and viewer, Mavipak
`the historical point of view.
`the historical point of view.
`transmitter, and Mavigraph video printer. The camera had a 280,000 pixel CCD sensor with red, green, and cyan
`transmitter, and Mavigraph video printer. The camera had a 280,000 pixel CCD sensor with red, green, and cyan
`stripes and the printer used thermal dye transfer technology with a 512-element heater. In 1986 Canon began
`stripes and the printer used thermal dye transfer technology with a 512 -element heater. In 1986 Canon began
`marketing its RC 701 ESC system in the U.S. The camera used a CCD sensor with 380,000 pixels. In 1988 Canon
`marketing its RC 701 ESC system in the U.S. The camera used a CCD sensor with 380,000 pixels. In 1988 Canon
`
`158 /SPIEVol. 1082 Applications of Electronic Imaging (1989)
`158 / SPIE Vol. 1082 Applications of Electronic Imaging (1989)
`
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`introduced a high resolution version of its ESC, RC 760, with a CCD sensor that has 600,000 pixels. Also in 1988 Fuji
`introduced a high resolution version of its ESC, RC 760, with a CCD sensor that has 600,000 pixels. Also in 1988 Fuji
`Photo Ltd. demonstrated its 400,000 pixel ESC, DS-1P, that employed a removable static, random access memory,
`Photo Ltd. demonstrated its 400,000 pixel ESC, DS -1P, that employed a removable static, random access memory,
`S-RAM card as the storage medium rather than the SVF disk. Polaroid demonstrated a monochrome ESC/motion
`S -RAM card as the storage medium rather than the SVF disk. Polaroid demonstrated a monochrome ESC /motion
`camera which recorded still images on S-VHS-compact cassettes. The other ESC systems use the SVF disks for
`camera which recorded still images on S- VHS -compact cassettes. The other ESC systems use the SVF disks for
`image storage. As can be seen from Table 1, the number of product entries are growing at a very rapid rate.
`image storage. As can be seen from Table 1, the number of product entries are growing at a very rapid rate.
`
`Electronic Still Camera
`Electronic Still Camera
`
`CAMERA
`
`IC
`
`I
`
`SOLO ST.E
`SOLID STATE
`SENSOR WITH
`
`-HYBRID SYSTEM-
`HYBRID SYSTEM
`
`CA
`
`GE
`
`EXPOSURE
`
`ESC SYSTEM
`
`IN CAMERA
`
`STORE
`STORE
`
`IComprauion)
`
`SOFT osv
`
`AECO.s.nucnoI
`
`WARD COPY
`
`NETWORK
`
`COMMUNICA
`
`COMMENTS
`COMMENTS
`First ESC demo
`First ESC demo
`64mm disc
`64mm disc
`Demo Camera
`Demo Camera
`Demo Camera
`Demo Camera
`Demo Camera
`Demo Camera
`Demo Camera
`Demo Camera
`Demo Camera
`Demo Camera
`Demo Camera
`Demo Camera
`First ESC sold in US
`First ESC sold in US
`
`LENS
`IMAGER
`MEDIA
`MODEL
`DATE
`IMAGER
`LENS
`MODEL
`MEDIA
`DATE
`16-64mm
`2/3" 280K
`Mavica
`Sony Mavica
`Aug 1981
`Mavica 2/3' 280K 16 -64mm
`Aug 1981 Sony Mavica
`2/3" 200K
`disc
`Toshiba
`Dec 1983
`2/3' 200K
`Dec 1983 Toshiba
`disc
`16-64mm
`2/3 " 400K
`SVF
`Canon
`July 1984
`2/3' 400K 16 -64mm
`July 1984 Canon
`SVF
`9-27mm
`SVF
`2/3 " 280K
`Copal CV-1
`Oct1984
`2/3 " 280K 9 -27mm
`Oct 1984 Copal CV -1
`SVF
`2/3"190K
`SVF
`Hitachi
`Nov 1984
`2/3' 190K
`Nov 1984 Hitachi
`SVF
`14-24mm,f/2
`SVG
`2/3" 300K
`Panasonic
`NOV1984
`2/3' 300K 14- 24mm,f/2
`Nov 1984 Panasonic
`SVG
`9-27mm
`2/3"280K
`SVF
`Sanyo
`Oct1985
`2/3' 280K 9 -27mm
`Oct 1985 Sanyo
`SVF
`SVF
`Mitsubishi
`Oct1985
`Oct 1985 Mitsubishi
`SVF
`11 -66mm
`2/3"380K
`SVF
`Canon RC 701
`May 1986
`2/3' 3801< 11 -66mm
`Canon RC 701
`SVF
`May 1986
`10&25mm. AF
`2/3"300K
`SVF
`Panosonic3100
`Sept 1986
`108.25mm, AF
`2/3' 300K
`Panosonic 3100
`Sept 1986
`SVF
`Demo Camera
`12-72mm.f/1.7
`2/3"250K
`SVF
`Chinon
`Nov 1986
`12- 72mm,f /t.7 Demo Camera
`2/3" 250K
`Nov 1986
`Chinon
`SVF
`11mmf/2.8
`2/3"280K
`SVF
`Casio VS-1 01
`Dec 1986
`2/3' 280K 11 mm 1/2.8
`Dec 1986 Casio VS -101
`SVF
`SVF
`Rollei
`Feb 1987
`Feb 1987 Rollei
`SVF
`12-72mm
`2/3"380K
`SVF
`Sony MVC-A7AF
`May 1987
`2/3' 380K 12 -72mm
`May 1987 Sony MVC -A7AF SVF
`12-36mm,AF
`2/3"300K
`SVF
`Konica KC 400
`June 1987
`2/3' 300K 12- 36mm,AF
`SVF
`June 1987 Konica KC 400
`Demo Camera
`SVF
`2/3"280K
`Kodak
`June 1987
`Demo Camera
`2/3' 280K
`June 1987 Kodak
`SVF
`x3Zoom
`SVF
`2/3"380K
`Fuji ES-1
`Sept 1987
`2/3' 380K x3 Zoom
`Sept 1987 Fuji ES -1
`SVF
`Maxxum camera back
`2/3"380K
`SVF
`Minolta SB-90
`Nov 1987
`Maxxum camera back
`2/3' 380K
`Nov 1987 Minolta SE -90
`SVF
`Binocular style
`11mmf/2.8
`2/3"300K
`SVF
`Konica KC 100
`Jan 1988
`Binocular style
`2/3' 300K 11 mm 1/2.8
`Jan 1988 Konica KC 100
`SVF
`CP-9AF Camera back
`Chinon
`SVF
`Jan 1988
`CP -9AF Camera back
`Jan 1988 Chinon
`SVF
`2/3"600K
`SVF
`Canon RC 760
`Mar 1988
`2/3' 600K
`Mar 1988 Canon RC 760
`SVF
`B/W Photojournalism
`x4/x11 Zoom
`2/3"380K
`SVF
`Nikon QV-1000C
`Sept 1988
`2/3' 380K x4 /x11 Zoom B/W Photojournalism
`Sept 1988 Nikon QV-1000C SVF
`$1400 list price
`12-25mm, AF
`Hi-SVF
`2/3"400K
`Fuji ES20
`Sept 1988
`Hi -SVF 2/3' 400K 12 -25mm, AF $1400 list price
`Sept 1988 Fuji ES20
`$700 list price
`1 1 mm f/2.8
`Hi-SVF
`1/2"360K
`Canon Q-PIC
`Sept 1988
`$700 list pace
`Hi -SVF 12' 360K 11 mm 1/2.8
`Sept 1988 Canon 0-PIC
`Binocular style
`x3 Zoom f/2.8
`Hi-SVF
`1/2" 360K
`Olympus V- 100
`Sept 1988
`Hi -SVF 12' 360K x3 Zoom 1/2.8 Binocular style
`Sept 1988 Olympus V -100
`$700 list price
`12mm f/2.8
`Hi-SVF
`1/2" 300K
`Konica KC300
`Oct1988
`Hi -SVF 12' 300K 12mm 1/2.8
`$700 list price
`Oct 1988 Konica KC300
`Commercial use ($2050)
`tele-wide
`Hi-SVF
`1/2"360K
`MatsushitaESIO
`Oct1988
`Commercial use ($2050)
`Oct 1988 Matsushita ES10 Hi -SVF 12' 360K tele -wide
`$650 list price
`auto focus
`Hi-SVF
`1/2"280K
`Sony 2MVC-C1
`Oct1988
`$650 list price
`Hi -SVF 12' 280K auto focus
`Oct 1988 Sony 2MVC -C1
`Business use (1950)
`9&16mm
`Canon RC-470
`Hi-SVF
`1/2"360K
`Oct1988
`Business use (1950)
`Hi -SVF 12' 360K 9816mm
`Oct 1988 Canon RC -470
`16MByteRAMcard
`16mm
`2/3"400K
`FujiDS-1P
`RAM
`Oct1988
`16 MByte RAM card
`2/3' 400K 16mm
`Oct 1988 Fuji DS-1P
`RAM
`B/W still & Motion
`12mmf/1.3
`2/3"550K
`Polaroid S/V-M
`S-VHS
`Oct1988
`B/W still 8 Motion
`2/3' 550K 12mm 1/1.3
`Oct 1988 Polaroid SN -M S -VHS
`$1600 list price
`Hi-SVF
`Minolta
`2/3"380K
`Nov 1988
`$1600 list price
`Hi -SVF 2/3' 380K
`Nov 1988 Minolta
`
`Camera back for 3001/3
`Camera back for 3001/3
`
`Figure 3. Functional outline of a hybrid imaging
`Figure 3. Functional outline of a hybrid imaging
`system and an electronic still camera system.
`system and an electronic still camera system.
`
`Table 1. Electronic still camera systems that have
`Table 1. Electronic still camera systems that have
`been demonstrated or placed on the market.
`been demonstrated or placed on the market.
`
`2. SYSTEM ANALYSIS
`2. SYSTEM ANALYSIS
`The end user, the customer, of an ESC will measure the quality of the system by how well the images it produces
`The end user, the customer, of an ESC will measure the quality of the system by how well the images it produces
`compare to the images that he or she can currently obtain from a conventional 35 mm film-based system. In this
`compare to the images that he or she can currently obtain from a conventional 35 mm film -based system. In this
`section the foundation will be laid for how to analyze the ESC system, and the results will be used in subsequent
`section the foundation will be laid for how to analyze the ESC system, and the results will be used in subsequent
`sections to demonstrate the importance of the separate technologies to the final image.
`sections to demonstrate the importance of the separate technologies to the final image.
`Figure 4 shows an image quality polygon. It is an attempt to graphically show the magnitude of the quality of each of
`Figure 4 shows an image quality polygon. It is an attempt to graphically show the magnitude of the quality of each of
`the major components of the ESC system. The radial, outward spokes indicate the level of quality of each of the
`the major components of the ESC system. The radial, outward spokes indicate the level of quality of each of the
`components normalized by some convenient scaling factor.
`components normalized by some convenient scaling factor.
`
`A short definition of each term will now be given.
`A short definition of each term will now be given.
`1. Resolution: for an ESC this is usually defined by the number of pixels per image sensor, but film systems
`1. Resolution: for an ESC this is usually defined by the number of pixels per image sensor, but film systems
`usually use the modulation transfer function, MTF, to define image resolution and sharpness, which is more
`usually use the modulation transfer function, MTF, to define image resolution and sharpness, which is more
`accurate.
`accurate.
`2. Sensitivity: this is equivalent to film speed and can be expressed as an equivalent ISO speed or the minimum
`2. Sensitivity: this is equivalent to film speed and can be expressed as an equivalent ISO speed or the minimum
`illumination (typically measured in lux) required to capture a high quality image.
`illumination (typically measured in lux) required to capture a high quality image.
`3. Exposure Latitude: this is the range in exposure over which the ESC can record subjectively determined
`3. Exposure Latitude: this is the range in exposure over which the ESC can record subjectively determined
`high quality images; the exposure latitude can be expressed in terms of a ratio, for example, 400:1, in terms of
`high quality images; the exposure latitude can be expressed in terms of a ratio, for example, 400:1, in terms of
`stops, about nine, or in absolute terms, 20 lux to 8000 lux.
`stops, about nine, or in absolute terms, 20 lux to 8000 lux.
`
`SPIE Vol. 1082 Applications of Electronic Imaging (1989) / 159
`SPIE Vol. 1082 Applications of Electronic Imaging (1989) / 159
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`4. Dynamic range: this refers to the effective exposure range of the image on the sensor that the ESC system
`4. Dynamic range: this refers to the effective exposure range of the image on the sensor that the ESC system
`can reproduce. If the exposure control mechanism of the ESC sets the operational point in the middle of the
`can reproduce. If the exposure control mechanism of the ESC sets the operational point in the middle of the
`possible exposure latitude, 4010 lux in the example above, the dynamic range would be plus -or -minus 3900
`possible exposure latitude, 4010 lux in the example above, the dynamic range would be plus-or-minus 3900
`lux, or a sensor dynamic range of 400:1, or a little less than nine stops. However, the best CRT displays can
`lux, or a sensor dynamic range of 400:1, or a little less than nine stops. However, the best CRT displays can
`properly display little more than a 40:1 contrast ratio. This then limits the dynamic range of the ESC system
`properly display little more than a 40:1 contrast ratio. This then limits the dynamic range of the ESC system
`to a little more than five stops. There is a direct parallel in the photographic system; while a color negative may
`to a little more than five stops. There is a direct parallel in the photographic system; while a color negative may
`have over ten stops in usable latitude, the system, including the limiting paper exposure latitude, may have a
`have over ten stops in usable latitude, the system, including the limiting paper exposure latitude, may have a
`net dynamic range between four and five stops.
`net dynamic range between four and five stops.
`
`5. Tone Reproduction: this is a measure of how well the final image gives the same appearance of the original
`5. Tone Reproduction: this is a measure of how well the final image gives the same appearance of the original
`scene in terms of overall contrast, shadow detail, and highlights. The physically measurable tone scale which
`scene in terms of overall contrast, shadow detail, and highlights. The physically measurable tone scale which
`produces the best subjective tone scale will vary depending on the viewing conditions; thus what is best for a
`produces the best subjective tone scale will vary depending on the viewing conditions; thus what is best for a
`soft display will not be the same as what is best for a reflection print, which is in turn different from what is best
`soft display will not be the same as what is best for a reflection print, which is in turn different from what is best
`for a projected transparency.
`for a projected transparency.
`
`6. Color reproduction: this refers to accurate reproduction of perceived color. While it is ideal to reproduce
`6. Color reproduction: this refers to accurate reproduction of perceived color. While it is ideal to reproduce
`exactly the perceived color of the original scene, this is neither feasible nor required. The most important
`exactly the perceived color of the original scene, this is neither feasible nor required. The most important
`aspects are to have good flesh -to- neutral balance, proper hue and good saturation for the basic memory
`aspects are to have good flesh-to-neutral balance, proper hue and good saturation for the basic memory
`colors, such as grass, blue sky, etc., no obvious color shifts, and no pronounced holes in the color reproduction
`colors, such as grass, blue sky, etc., no obvious color shifts, and no pronounced holes in the color reproduction
`space.
`space.
`7. Artifacts: these are unnatural occurrences in the image introduced by the various components of the ESC
`7. Artifacts: these are unnatural occurrences in the image introduced by the various components of the ESC
`system. Two of the most obvious are due to the aliasing introduced by the low spatial sampling of the image
`system. Two of the most obvious are due to the aliasing introduced by the low spatial sampling of the image
`resulting in too few pixels and quantization distortions which can occur if the the amplitude of the signal is
`resulting in too few pixels and quantization distortions which can occur if the the amplitude of the signal is
`recorded with too few bits; the resulting contours are easily seen and very displeasing.
`recorded with too few bits; the resulting contours are easily seen and very displeasing.
`
`8. Noise: in solid state image sensors this is usually quantified by the non-image electrons associated with the
`8. Noise: in solid state image sensors this is usually quantified by the non -image electrons associated with the
`sensor, output of the sensor, and its support electronics. The noise will appear as random noise or grain in the
`sensor, output of the sensor, and its support electronics. The noise will appear as random noise or grain in the
`final print. From the point of view of a television engineer noise is measured as the ratio of the peak amplitude
`final print. From the point of view of a television engineer noise is measured as the ratio of the peak amplitude
`level, in volts, of the desired signal to the root-mean-square (RMS) average of the noise. This ratio is often
`level, in volts, of the desired signal to the root -mean -square (RMS) average of the noise. This ratio is often
`expressed in decibels which is 20 times the log to the base ten of the ratio.
`expressed in decibels which is 20 times the log to the base ten of the ratio.
`
`Tone Reproduction, T
`Tone Reproduction, T
`
`Resolution, R
`Resolution, R
`Sensitivity, S
`Sensitivity, S
`
`Noise, N
`Noise, N
`
`Artifacts, A
`Artifacts, A
`
`Exposure Latitude, EL
`Exposure Latitude, EL
`
`Dynamic Range, DR
`Dynamic Range, DR
`Color Reproduction, C
`Color Reproduction, C
`(A)
`(A)
`R
`R
`
`C
`(B)
`
`MTF
`
`1.0
`
`09
`
`08
`
`07
`
`06
`
`05
`
`04
`
`03
`
`02
`
`01
`
`0
`
`0.1
`
`-•Sensor: MTF= sin (TrDf)/rrDf
`Sensor MTF =sin (irDf(lrrDf
`
`Normalize at MTF=0.5
`Normalize at MTF =0.5
`Df = 1.9
`f = 50 c/mm
`D=0.012 mm
`
`10
`
`20 30 40 50 60 70
`90 100 110 120 130 140
`80
`70 80X90 100 110 120 130 140
`40 50 60
`Spatial frequency
`
`Figure 4. The quality polygon. A. The length of the
`Figure 4. The quality polygon. A. The length of the
`radial arm is proportional to the quality of the
`radial arm is proportional to the quality of the
`designated characteristic. B. The quality charac-
`designated characteristic. B. The quality charac(cid:173)
`teristics are not independent and if the sensitivity
`teristics are not independent and if the sensitivity
`is increased there may be a drop in resolution
`is increased there may be a drop in resolution
`(sharpness) and an increase in visual artifacts.
`(sharpness) and an increase in visual artifacts.
`
`Figure 5. A method to calculate the effective pixel
`Figure 5. A method to calculate the effective pixel
`size that can be associated with photographic film
`size that can be associated with photographic film
`when a frame transfer device with square pixels is
`when a frame transfer device with square pixels is
`assumed as the sensor model. The curve shown
`assumed as the sensor model. The curve shown
`for the film is based on a theoretical model and
`for the film is based on a theoretical model and
`does not represent a particular film.
`does not represent a particular film.
`
`160 / SPIE Vol. 1082 Applications of Electronic Imaging (1989)
`160 / SPIE Vol. 1082 Applications of Electronic Imaging (1989)
`
`4
`
`

`

`The image quality polygon can be used to compare systems as shown in Figure 4. Here system A has higher
`The image quality polygon can be used to compare systems as shown in Figure 4. Here system A has higher
`sensitivity than system B, but the price paid for the increased sensitivity is that the resolution is lower and there are
`sensitivity than system B, but the price paid for the increased sensitivity is that the resolution is lower and there are
`more artifacts. As will be demonstrated in the following sections, these image quality parameters are not independ(cid:173)
`more artifacts. As will be demonstrated in the following sections, these image quality parameters are not independ-
`ent. Within any given set of technolo