EP0537341A1 - Camera a deux normes utilisant un capteur ccd commun - Google Patents

Camera a deux normes utilisant un capteur ccd commun

Info

Publication number
EP0537341A1
EP0537341A1 EP92917289A EP92917289A EP0537341A1 EP 0537341 A1 EP0537341 A1 EP 0537341A1 EP 92917289 A EP92917289 A EP 92917289A EP 92917289 A EP92917289 A EP 92917289A EP 0537341 A1 EP0537341 A1 EP 0537341A1
Authority
EP
European Patent Office
Prior art keywords
pal
signals
ntsc
sensor
image
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP92917289A
Other languages
German (de)
English (en)
Inventor
Kenneth Alan Parulski
Paul Ralph Shelley
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Eastman Kodak Co
Original Assignee
Eastman Kodak Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
Publication of EP0537341A1 publication Critical patent/EP0537341A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/40—Extracting pixel data from image sensors by controlling scanning circuits, e.g. by modifying the number of pixels sampled or to be sampled
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/70—SSIS architectures; Circuits associated therewith
    • H04N25/71—Charge-coupled device [CCD] sensors; Charge-transfer registers specially adapted for CCD sensors
    • H04N25/73—Charge-coupled device [CCD] sensors; Charge-transfer registers specially adapted for CCD sensors using interline transfer [IT]

Definitions

  • Television cameras with tube sensors can be switched between NTSC and PAL line rates, so that they scan the appropriate number of lines per frame, by changing the beam deflection circuitry.
  • Television cameras that use semiconductor image sensors, such as CCD sensors must be designed with a fixed number of pixels in the vertical and horizontal directions and a fixed picture aspect ratio.
  • an expensive digital "standards converter” which interpolates 575 new active PAL lines from the camera's 484 NTSC lines, and changes the frame rate, has to be used.
  • standards converters are available, for example, from AF Associates, Northvale, New Jersey.
  • the present invention provides a simple, low cost video camera which can be switched to generate either PAL or NTSC signals and which uses a standard - semiconductor image sensor array, such as a CCD image sensor, without adding additional lines of photoelements to the array, and without requiring special line selection circuitry incorporated on the image sensor.
  • a standard - semiconductor image sensor array such as a CCD image sensor
  • a PAL/NTSC camera having a common CCD image sensor array for selectively providing PAL and NTSC outputs incorporating an NTSC format image sensor array for converting a sensed image to corresponding output electrical signals at a rate determined by horizontal and vertical timing signals.
  • a timing signal generator selectively provides a first set of vertical and horizontal timing signals to the image sensor array for generating NTSC output signals and a second set of vertical and horizontal timing signals to the image sensor array for generating PAL output signals.
  • the output signals are directed to a processor for providing processed output signals for display on a picture monitor.
  • the camera timing allows the NTSC picture monitor to show the normal full screen image.
  • the camera timing is modified so that the PAL monitor displays a "windowed" 484 line image with the proper aspect ratio and no geometric distortion. This is accomplished by extending both the vertical and horizontal blanking times by 16% and increasing the horizontal sensor clock rate by 16%.
  • the image on the PAL monitor can be centered, or moved to a corner of the screen, to allow text or graphics to be placed outside the window.
  • Figure 1 illustrates a block diagram of an NTSC format CCD sensor.
  • Figure 2 illustrates the number of lines, pixels and aspect ratio required for displaying an image on an NTSC video monitor.
  • Figure 3 illustrates the displaying of a centered window image from an NTSC format sensor on a PAL video monitor.
  • Figure 4 illustrates an upper right corner offset window of the image of Figure 3 on the PAL video monitor.
  • Figure 5 is a block schematic diagram of the preferred embodiment of the present invention.
  • Figure 6 is a timing diagram showing some signals provided by the timing generator of Figure 5 when providing an NTSC output signal.
  • Figure 7 is a timing diagram showing some signals provided by the timing generator of Figure 5 when providing a PAL output signal with a centered window image.
  • Figure 8 is a timing diagram showing some signals provided by the timing generator of Figure 5 when providing a PAL output signal with an upper right corner offset window image.
  • Figure 1 illustrates an NTSC format CCD sensor 10 which may be a Kodak KAI-0370C sensor manufactured by Eastman Kodak Company, Rochester, New York.
  • the sensor 10 has 484 vertical by 768 horizontal active photosites and a 4:3 aspect ratio to create the NTSC format image shown in Figure 2. While the present invention is described relative to the KAI-0370C sensor, any other NTSC format sensor may be used.
  • the number of active lines and the picture aspect ratio of the sensor 10 are chosen to be compatible with the RS- 170A 'NTSC standard, such that properly encoded signals from this sensor can be displayed on an NTSC monitor 40 (illustrated in Figure 5) .
  • the display update rate of NTSC monitor 40 is 59.94 fields per second, where two interlaced fields, each composed of 242 displayed lines, comprise one frame.
  • the number of active lines of the CCD sensor 10 is equal to the number of displayed lines of monitor 40.
  • the number of horizontal pixels in an NTSC image sensor is somewhat arbitrary, although there are advantages to choosing this number such that the sensor horizontal readout frequency is a multiple of the NTSC color sub-carrier frequency, which is approximately 3.58 MHz.
  • the sensor horizontal readout frequency depends on the number of pixels and the active line period during which the pixels are read out, which for the RS-170A standard is approximately 52.46 microseconds.
  • the KAI-0370C clock frequency used for NTSC display is equal to four times the NTSC subcarrier frequency, or approximately 14.32 MHz.
  • the PAL-B color television standard is also based on a 4:3 picture aspect ratio, but employs approximately 575 active lines, instead of the 484 active lines used in NTSC ( Figure 3).
  • the PAL-B display update rate is exactly 50.00 fields per second, and the active line time is approximately 51.95 microseconds. Because there are fewer active lines in the NTSC sensor than in the PAL display, there is no way to create a full screen image on a PAL display from the NTSC sensor, unless the extra lines are digitally interpolated in an NTSC to PAL standards converter, which is an expensive and unattractive solution in this application.
  • the inventors of the present invention have recognized, however, that for many scientific and medical applications, it is not necessary to have a full screen image on the PAL display. Instead, the 484 active lines from the NTSC sensor can be directly displayed on 484 PAL lines, and the remaining 91 active lines on the PAL display can be set to black, or used for other purposes. However, it is critical that the displayed 484 line image on the PAL monitor be stable, and contain no geometric distortion.
  • One way to provide a viewable image on a PAL monitor from the KAI- 0370C NTSC.sensor is to read out the 484 lines of the image sensor during the middle 484 lines of the PAL display, using a clock-, frequency equal to the number of horizontal pixels divided by the PAL active line time, which equals approximately 768/0.00005195, or 14.78 MHz.
  • the displayed picture aspect ratio would be wrong, and objects would be displayed much wider than they really are.
  • the inventors of the present invention have recognized that in order to prevent geometric distribution, the horizontal dimension of the image from the NTSC sensor on the PAL monitor must be equal to 484/575 times the PAL active display width. This is true because in order to display an undistorted image on a PAL monitor, the image aspect ratio of the display must equal that of the image as captured by the sensor, which is 4:3. Since the picture on the PAL display from the NTSC sensor is compressed by about 16% in the • vertical direction, because only 484 out of 575 lines are displayed, the picture must also be compressed by the same 16% factor in the horizontal direction, in order to prevent geometric distortion.
  • the proper horizontal clock frequency for the KAI-0370C sensor needed to obtain an undistorted PAL display therefore equals approximately 768/0.00004364, or approximately 17.60 MHz.
  • the PAL display will appear as shown in Figure 3.
  • the outer 16% of the PAL display will be black due to blanking, but the image in the center of the screen will be properly displayed. .
  • the 17.60 MHz clock frequency provides 912 pixel clock periods during the PAL-B active line period.
  • Figure 5 illustrates the combination of an • NTSC/PAL camera 20 which uses an KAI-0370C NTSC format sensor 10, a model KDSP-A100 CFA processor 13, and a model KDSP-A230 RGB post-processor 14, which are manufactured by Eastman Kodak Company, Rochester, New York, and which are described in the publication "A Digital Color Imaging System using Custom VLSI Circuits", authored by K.A. Parulski, et. al., IEEE Trans, on Consumer Electronics, Vol. 35, No. 3, pp. 382-389, Aug. 1989.
  • a timing generator 17 which can be an integrated circuit of the type described in "The EBS-1, an EPROM-Based Sequencer ASCI," CICC '88 Technical Digest, pp. 15.6.1-15.6.4, May 1988, and a color encoder 16 which can be an integrated circuit NTSC/PAL encoder model MC 1377 available from Motorola, Inc., Phoenix, Arizona. Additionally, there is provided an analog signal processor 11, an A/D converter 12, a 3-channel D/A converter 15 and four selectable oscillators, 18, 19, 21, and 22 which provide the labeled output signals when selected by switches 24 and 26.
  • the camera 20 can be switched from providing an NTSC signal for driving the NTSC monitor 40 to providing a PAL signal for driving a PAL monitor 50. This can be controlled by the switches labeled 23-27. For operator convenience, switches 23-26 may be ganged together to form one user controlled switch.
  • The-sensor 10 receives different control signals from the timing generator 17 through voltage translators 28, depending on the status of the PAL/NTSC mode switch 23.
  • the voltage translators convert the 0 to 5 volt logic signals supplied by timing generator 17 to the appropriate voltage levels required by sensor ' 10, for example -8 to +7 volt signals for the vertical CCD clocks, ⁇ V, and -9 to +2 volts for the horizontal CCD clocks, ⁇ H, using circuits well-known to those skilled in the art.
  • the timing generator 17 is programmed to generate the appropriate timing signals for NTSC or PAL operation of the sensor 10 and all the other major camera components, when switches 23 and 24 are set properly.
  • FIG 6 shows the signals supplied by timing generator 17 to the sensor 10 in the NTSC mode.
  • Timing waveforms 102 and 104 control when the 489 lines of photoelements of the KAI-0370C sensor (484 active lines plus 5 lines of light shielded pixels) are transferred to the horizontal register 9 in Figure 1, by controlling the vertical clocks VI an ⁇ V2 supplied to sensor 10.
  • Waveforms 102 and 104 include 495 pulses per frame because 6 additional clock phases per frame are needed to transfer the 489 lines of photoelements into the horizontal readout registers.
  • Waveforms 106, 108, 110, and 112 show ⁇ VI and ⁇ V2 in greater detail during the odd field and even field vertical blanking intervals.
  • Pulses 107 and 111 control the transfer of the photodiode signal charge to the vertical transfer registers 7 in Figure 1.
  • Pulses 109 and 113 indicate that the first line of light shielded pixels is transferred to the horizontal register 9 at the start of video Line Number 17 of the odd and even fields, so that the active video image is available at the end of the normal NTSC vertical blanking interval.
  • Waveforms 114 and 116 show ⁇ VI and ⁇ V2 in greater detail during the period corresponding to one NTSC line.
  • Waveforms 120 and 122 show how horizontal clocks ⁇ H1 and ⁇ H2 are controlled in order to read out the charge in the horizontal register 9 via a floating diffusion output structure 8 shown in Figure 1.
  • ⁇ H1 and ⁇ H2 are cycled high and low 791 times in order to read out the 768 photoactive pixels, 12 dark reference pixels, 9 leading empty shift register phases, and 2 trailing empty shift register phases, as indicated by line content diagram 126.
  • ⁇ R signal 124 is used to reset the floating diffusion output structure 8 of Figure 1 after each pixel transfer is complete.
  • Timing waveforms 120, 122, and 124 indicate that ⁇ H1, ⁇ H2 and ⁇ R operate at a 14.32 MHz clock frequency, and that ⁇ H1 and ⁇ H2 are active for approximately 55.3 ⁇ secs, so that the active video image is read out during the normal NTSC active video line period.
  • Figure 7 shows the signals supplied by timing generator 17 to the sensor 10 in the PAL mode, with a "centered" image window as shown in Figure 3.
  • Timing waveforms 202, 204, 206, 208, 210 and 212 control when the 489 lines of photoelements of the KAI-0370C sensor are transferred to the horizontal register. Since there are 45 fewer lines per field on the KAI-0370C sensor compared to PAL format sensors, the first line transfer of each field, is delayed by an additional 23 lines until Line Number 45, as indicated by pulses 209 and 213, to provide a vertically centered image.
  • Timing waveforms 214, 216, 220, 222, and 224 show the 64.0 ⁇ sec. PAL line time in more detail. Waveforms 220 and 222 show how the horizontal clocks ⁇ H1 and ⁇ H2 are cycled high and low 791 times in a period of 44.9 ⁇ sec, corresponding to a horizontal clock frequency of 17.60 MHz, during the middle of the PAL line.
  • Figure 8 shows the timing signals supplied by timing generator 17 to the sensor 10 in the PAL mode, with an "upper right corner offset" window image.
  • Either the timing generator 17 can be programmed to supply these signals in the PAL mode, instead of those shown in Figure 7, or else a switch input to timing generator 17 (not shown) can be used to select whether the signals in Figure 7 (corresponding to the centered PAL window in Figure 3) or the signals in Figure 8 (corresponding to the offset PAL window in Figure 4) are used when in the PAL mode.
  • Timing waveforms 302, 304, 306, 308, 310 and 312 show that the first line transfer of each field occurs at Line Number 22, as indicated by pulses 309 and 313, so that the image is displayed at the top of the PAL monitor, with 45 black lines per field at the bottom of the display.
  • Timing waveforms 314, 316, 320 and 322 show the 64.0 ⁇ sec. PAL line time in more detail. Waveforms 320 and 322 show how the horizontal readout period is shifted to the end of the active line period, instead of the middle of the line period as was the case with waveforms 220 and 222 in Figure 7. Selection of Line Numbers between 22 ( Figure 7) and 67 for the first line transfer will move the image (as a function of the selected Line Number) from the top to the bottom of the screen.
  • the color encoder 16 is designed to create either PAL or NTSC color signals, when the PAL/NTSC mode switch 25 is properly set, when the RGB signals from D/A converter 15 follow the proper PAL or NTSC scanning standards, and when the proper color sub- carrier frequency is applied to the color oscillator input to the encoder 16 via the switch 26. Viewing ⁇ of the output on either the NTSC monitor 40 or the PAL monitor 50 is controllable by the position of switch 27.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Transforming Light Signals Into Electric Signals (AREA)

Abstract

La présente invention se rapporte à une caméra vidéo qui utilise un capteur d'images CCD commun pour produire des signaux de sortie en PAL et NTSC. Le capteur d'images convertit une image détectée en signaux de sortie électriques correspondants, à un taux déterminé par des signaux de synchronisation horizontaux et verticaux. Un générateur de signaux de synchronisation fournit de façon sélective un premier ensemble de signaux verticaux et horizontaux au capteur d'image afin de produire de signaux de sortie en NTSC, et un second ensemble de signaux verticaux et horizontaux afin de produire des signaux de sortie en PAL. Un processeur traite les signaux de sortie produits par la générateur afin de produire des signaux de sortie traités de façon à être affichés sur un dispositif d'affichage soit sous forme de signaux PAL, soit sous forme de signaux NTSC.
EP92917289A 1991-05-01 1992-04-28 Camera a deux normes utilisant un capteur ccd commun Withdrawn EP0537341A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US69416791A 1991-05-01 1991-05-01
US694167 1991-05-01

Publications (1)

Publication Number Publication Date
EP0537341A1 true EP0537341A1 (fr) 1993-04-21

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Application Number Title Priority Date Filing Date
EP92917289A Withdrawn EP0537341A1 (fr) 1991-05-01 1992-04-28 Camera a deux normes utilisant un capteur ccd commun

Country Status (3)

Country Link
EP (1) EP0537341A1 (fr)
JP (1) JPH05508287A (fr)
WO (1) WO1992020187A1 (fr)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19514629A1 (de) * 1995-04-26 1996-10-31 Thomson Brandt Gmbh Videokamera mit Weißabgleich
JP2000032441A (ja) 1998-07-10 2000-01-28 Fuji Photo Optical Co Ltd Ｎｔｓｃ及びｐａｌの両方式を備えた内視鏡用撮像装置
AU2003242787A1 (en) * 2002-06-07 2003-12-22 Thomson Licensing S.A. Multi-format camera head
JP2006115413A (ja) * 2004-10-18 2006-04-27 Toshiba Corp 撮像装置と撮像方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2913116A1 (de) * 1979-04-02 1980-10-23 Bosch Gmbh Robert Verfahren zum auslesen von festkoerper- bildsensoren und schaltungsanordnung zur durchfuehrung des verfahrens
JPS62261332A (ja) * 1986-05-08 1987-11-13 オリンパス光学工業株式会社 電子式内視鏡装置
FR2659183A1 (fr) * 1990-03-02 1991-09-06 Visuel Plus Dispositif de branchement d'une console de jeux video.

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9220187A1 *

Also Published As

Publication number Publication date
JPH05508287A (ja) 1993-11-18
WO1992020187A1 (fr) 1992-11-12

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