+

WO1993014595A1 - Procede et appareil d'augmentation de la gamme dynamique de capteurs optiques - Google Patents

Procede et appareil d'augmentation de la gamme dynamique de capteurs optiques Download PDF

Info

Publication number
WO1993014595A1
WO1993014595A1 PCT/US1993/000512 US9300512W WO9314595A1 WO 1993014595 A1 WO1993014595 A1 WO 1993014595A1 US 9300512 W US9300512 W US 9300512W WO 9314595 A1 WO9314595 A1 WO 9314595A1
Authority
WO
WIPO (PCT)
Prior art keywords
time
pulses
optical sensor
reset
pulse
Prior art date
Application number
PCT/US1993/000512
Other languages
English (en)
Inventor
Orly Yadid-Pecht
Original Assignee
Barish, Benjamin, J.
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 Barish, Benjamin, J. filed Critical Barish, Benjamin, J.
Publication of WO1993014595A1 publication Critical patent/WO1993014595A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/70—Circuitry for compensating brightness variation in the scene
    • H04N23/71—Circuitry for evaluating the brightness variation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/70—Circuitry for compensating brightness variation in the scene
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/50—Control of the SSIS exposure
    • H04N25/57—Control of the dynamic range

Definitions

  • the present invention relates to a method and apparatus for increasing the dynamic range of optical sensors, e.g., for receiving viewable light or infrared thermal radiation.
  • the invention is particularly useful for increasing the dynamic range of video cameras or other optical sensors including a matrix or array of photo-sensitive elements and is therefore described below particularly with respect to such applications.
  • a known problem that exists today in optical sensors is the limited dynamic range of the photo-sensitive elements.
  • the photo-sensitive elements commonly have a dynamic range of two to three orders of magnitude, while the range of illumination levels that they may be exposed to may be as high as eight or more orders of magnitude.
  • the optical sensor is to sense a person in a darkened room standing near a lit window, the details outside the window which are at a high illumination level cannot be perceived together with the details of the person's face which are at a much lower illumination level. Under these conditions, the optical sensors encounter such problems as "blooming" .
  • the present invention provides a novel method and apparatus for increasing the dynamic range of an optical sensor to overcome the above problems .
  • a method of increasing the dynamic range of an optical sensor by controlling the integration time during which the optical sensor integrates the light received thereon and produces an electrical output corresponding thereto comprising: generating a series of regular reset pulses separated by prefixed time intervals of equal duration; generating a series of sample pulses each at a predetermined time interval after the generation of a regular reset pulse, which predetermined time interval represents a full integration time; generating a series of reset enable pulses at time intervals, between pulses, of shorter duration than that of the regular reset pulses; generating a control signal whenever a predetermined characteristic of the electrical output of the optical sensor exceeds a reference value; generating a conditional reset pulse whenever there is coincidence between a reset enable pulse and a control signal; starting the integration of the optical sensor at the time of generation of either a regular reset pulse or a conditional reset pulse; terminating the integration of the
  • the effective integration time is determined by counting the number of conditional reset pulses between the generation of a regular reset pulse and a sample pulse.
  • the reset enable pulses are generated at prefixed, but unequal time periods.
  • the time intervals to the next sample pulse decrease according to a downgoing geometric series .
  • the invention is particularly useful with respect to optical sensors, such as video cameras, which include a rectangular matrix or other array of photo-sensitive elements. When so used, it is preferable that the integration times of a block of photo-sensitive elements be controlled simultaneously by the control signal, although it is conceivable that each photo-sensitive elements can be individually controlled.
  • such a method can increase the dynamic range of an optical sensor in a real time manner so as to substantially reduce the above-mentioned "blooming" problem.
  • Fig. 1 illustrates one form of optical sensor whose dynamic range may be increased in accordance with the present invention
  • Fig. 2 illustrates a conventional (prior art) circuitry for normally controlling the integration time of each photo-sensitive element in a matrix-type optical sensor
  • Fig. 3 is a timing diagram illustrating the conventional (prior art) manner of controlling integration times according to Fig. 2;
  • Fig. 4 illustrates one form of control circuit in accordance with the present invention which may be used for controlling the integration time of the optical sensor illustrated in Fig. 1;
  • Figs. 4a, 4b and 4c illustrate examples of preferred ways of deriving the control signal in the control circuit of Fig. 4;
  • Fig. 5 is a timing diagram illustrating one example for operating the control signals of Fig. 4;
  • Fig. 6 schematically illustrates an example of a circuit for producing an output corresponding to the increased dynamic range of the optical sensor
  • Fig. 7 illustrates one form of digital circuit which may be used for determining the effective integration time in the novel method
  • Fig. 8 illustrates one form of analog circuit that may be used for determining the effective integration time in the novel method.
  • an optical sensor generally designated 10, including a rectangular matrix of photo-sensitive elements 11, 12, 13, etc., as may be found in a conventional video camera.
  • Each of the photo-sensitive elements 11-13 outputs an electrical signal corresponding to the amount of light received thereby in a predetermined time period, called the integration time.
  • Figs. 2 and 3 illustrate the manner of determining the integration time in a conventional system.
  • each photo-sensitive element, therein designated 21 is controlled by a transistor 23 receiving a series of regular reset pulses RST via line 22, separated by predetermined time intervals of equal duration.
  • a second transistor 24 is supplied with a series of sample pulses SMPL at a predetermined interval after the generation of a regular reset pulse RST.
  • the normal integration time in a conventional video camera is the time from the end of a reset pulse RST to be the beginning of the sample pulse SMPL. This is called the full integration time of the photo-sensitive elements.
  • the circuit illustrated in Fig. 2 may include a storage element 26. This storage element, however, can be omitted when the readout is directly to the video line via readout circuit 27, for example.
  • the integration time is the same for all the photo-sensitive elements. As pointed out earlier, however, when the illumination is high at a certain part of the picture, the integration time would be too long as the sensor would enter into saturation. On the other hand, in other parts of the picture where the illumination is weak, the integration time would be too low, producing a low output voltage such that the background noise might mask the signal.
  • the integration time of the photo-sensitive elements are not necessarily the full integration time as described above and as illustrated in Figs. 2 and 3, but rather may be shortenend, to produce a shorter effective integration time, according to the amount of light received by the photo ⁇ sensitive elements at that particular instance.
  • the photo-sensitive elements are arranged in blocks, as shown at 15, each block including a plurality of such elements.
  • Each block further includes a control circuit, schematically shown at 17, for controlling the effective integration time for the respective block.
  • Fig. 1 illustrates each block as comprising a plurality of photo-sensitive elements, which is generally preferred, it is contemplated that a block may consist of a single photo-sensitive element so that the photo-sensitive elements are controlled individually rather than in blocks.
  • the effective integration time for each block of sensors is determined and is used for computing the outputs of the photo-sensitive elements as appearing in the output line 18, Fig. 1.
  • the electrical output appearing on output line 18 is subsequently multiplied by a scaling factor, e.g., as illustrated in Fig. 6 to be described below, so that it will more closely correspond to the amount of light actually received by the photo-sensitive elements in the respective frame. In this manner, the dynamic range of the photo-sensitive elements is effectively increased.
  • a control circuit 17 (Fig. 1) that may be used for increasing the dynamic range of the optical sensor is illustrated in Fig. 4.
  • Such a circuit also includes, as in the conventional system, means for generating a series of regular reset pulses RST separated by prefixed time intervals of equal duration, and a series of sample pulses SMPL, each at a predetermined time interval after the generation of a regular reset pulse RST.
  • a full integration time is equal to the time from the end of the reset pulse RST to the beginning of the sample pulse SMPL.
  • the control circuit illustrated in Fig. 4 may produce an "effective" integration time which is shorter than the full integration time defined by the regular reset pulses RST and the sample pulses SMPL.
  • the circuit illustrated in Fig. 4 further include means for generating a control signal CS corresponding to a predetermined characteristic of the optical sensor.
  • This control signal CS may be derived from one of the photo-sensitive elements within the respective block 15, e.g., the centermost element as shown in Fig. 4a.
  • Another alternative is to have the control signal derived from the weighted average illumination level of photo ⁇ sensitive elements in the respective block as shown in Fig. 4b.
  • a further alternative is to derive the control signal CS in the manner illustrated in Fig. 4c, namely from a weighted average, produced by circuit 20, in the illumination levels of the surrounding area, e.g., blocks 15a-15d, including the controlled block 15.
  • This control signal CS is applied via lead 32, together with a reference signal Vref applied via lead 33, to a comparator 34, which produces an output whenever the control signal CS exceeds the reference signal Vref.
  • the circuit illustrated in Fig. 4 further includes means for generating a series of reset enable pulses RSTE at time intervals, between pulses, of shorter duration than that of the regular reset pulses RST.
  • Fig. 5 illustrates a preferred example of the timing of the reset enable pulses RSTE as compared to the regular reset pulses RST and the sample pulses SMPL. In the example illustrated in Fig.
  • the reset enable pulses RSTE are generated at prefixed, but unequal, time periods decreasing according to the following downgoing geometric series: T/X, T/X , T/X , T/X n wherein T is the full integration time (as determined by the ending by the regular reset pulse RST at the beginning of the sample pulse SMPL), and "X " is a preselected constant, for example, "X" may equal "2".
  • the reset enable pulses RSTE are applied via lead 35 to a transistor 39, such that when an output pulse is produced from the comparator 34 in coincidence with a reset enable pulse RSTE, the transistor 39 produces a conditional reset pulse CRST.
  • the so produced conditional reset pulse CRST is applied via lead 36 to an OR-gate 38 together with the regular reset pulse RST applied via lead 37, so that gate 38 produces an output on line 38A upon the occurrence of either pulse.
  • OR-gate 38 The output from OR-gate 38 is applied to a transistor 40 for each photo-sensitive element in the block 15 to start the integration time of the respective photo ⁇ sensitive elements.
  • the sample pulses SMPL are applied via lead 41 to another transistor 42 to terminate the integration time for the respective photo-sensitive elements.
  • the voltages produced by the photo-sensitive elements during this integration time are read out via readout circuit 43 to the output line 18. It will thus be seen that for each photo-sensitive element in the respective block 15, a conditional reset pulse CRST will be generated whenever the characteristic (e.g., illumination level) represented by control signal CS exceeds a reference (represented by a signal Vref) during the time of the generation of a reset enable pulse RSTE.
  • a conditional reset pulse CRST will be generated whenever the characteristic (e.g., illumination level) represented by control signal CS exceeds a reference (represented by a signal Vref) during the time of the generation of a reset enable pulse RSTE.
  • the integration time will restart upon the generation of either a conditional reset pulse CRST or a regular reset pulse RST.
  • the full integration time will be provided by the regular reset pulses RST; however, for those photo ⁇ sensitive elements which receive relatively high levels of illumination, the integration time will be shortened by the conditional reset pulses CRST so that those elements do not go into saturation.
  • the electrical output of the photo-sensitive elements is then multiplied by a scaling factor representing the ratio of the full integration time to the effective — o —
  • Fig. 6 The latter operation is schematically shown in Fig. 6, wherein it will be seen that the video output from the photo-sensitive elements in the matrix are applied via output line 18 to an analog-to-digital converter 50 and converted to digital values before being applied to a multiplier 52.
  • the multiplier 52 also receives, via input lead 54, the effective integration time for the respective photo-sensitive elements, determines the scaling factor, i.e., the ratio of the full integration time to the effective integration time, and multiplies the value outputted by the photo-sensitive elements by this scaling factor. For example, if the effective integration time was one-fourth the full integration time, the scaling factor would be "4", and the value outputted by the respective photo-sensitive elements would therefore be multiplied by "4". Thus, the output on line 56 more closely corresponds to the amount of illumination actually received by the respective photo-sensitive elements.
  • the effective integration time may be determined by counting the number of conditional reset pulses CRST.
  • Fig. 7 illustrates a digital circuit that may be used for this purpose, including a counter having flip-flops 71 , 72 constituting a two-bit counter 75, and two further flip-flops 73, 74 constituting a two-bit register 76, for storing the number of conditional reset pulses CRST.
  • Fig. 8 illustrates an analog circuit that may be used for this purpose, including a capacitor 81 which is charged each time a regular reset pulse RST is generated, and is discharged each time a conditional reset pulse CRST is generated, such that the charge in capactitor 81 will be proportional to the number of conditional resets. This value is stored in the capacitor 82.
  • the effective integration time can be determined by a heuristic algorithm or other means, within or outside the chip, instead of by counting the conditional reset pulses. While the illustrated examples are based on MOS technology, the method and apparatus can also be used in other semiconductor technologies, e.g., CCD and CID. Many other variations, modifications and applications of the invention will be apparent.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)
  • Transforming Light Signals Into Electric Signals (AREA)

Abstract

L'invention concerne un procédé et un appareil d'augmentation de la gamme dynamique d'un capteur optique (10) consistant à produire des impulsions de validation de remise à zéro (RSTE) à des intervalles de temps de durée plus courte que ceux des impulsions de remise à zéro normale, un signal de commande (CS) lorsqu'une caractéristique prédéterminée de la sortie du capteur déplace une valeur de référence, ainsi qu'une impulsion de remise à zéro conditionnelle (RST) lorsque se produit une coïncidence entre une impulsion de validation de remise à zéro (RSTE) et un signal de commande (CS). L'intégration du capteur (10) débute au moment de la production de n'importe quelle impulsion de remise à zéro normale (RST), et elle s'achève au moment de la production d'une impulsion d'échantillonnage. La sortie du capteur (10) est multipliée par un facteur de mise à l'échelle représentant le rapport du temps d'intégration total jusqu'au temps d'intégration effective entre les temps de début et de fin.
PCT/US1993/000512 1992-01-09 1993-01-06 Procede et appareil d'augmentation de la gamme dynamique de capteurs optiques WO1993014595A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IL10062092A IL100620A (en) 1992-01-09 1992-01-09 Method and apparatus for increasing the dynamic range of optical sensors
IL100620 1992-01-09

Publications (1)

Publication Number Publication Date
WO1993014595A1 true WO1993014595A1 (fr) 1993-07-22

Family

ID=11063251

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1993/000512 WO1993014595A1 (fr) 1992-01-09 1993-01-06 Procede et appareil d'augmentation de la gamme dynamique de capteurs optiques

Country Status (3)

Country Link
AU (1) AU3587493A (fr)
IL (1) IL100620A (fr)
WO (1) WO1993014595A1 (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5565915A (en) * 1993-06-15 1996-10-15 Matsushita Electric Industrial Co., Ltd. Solid-state image taking apparatus including photodiode and circuit for converting output signal of the photodiode into signal which varies with time at variation rate depending on intensity of light applied to the photodiode
EP0885456A4 (fr) * 1996-11-11 1998-12-23
WO2000024190A1 (fr) * 1998-10-19 2000-04-27 Ben-Gurion University Of The Negev Imageur optique utilisant un procede d'expansion adaptative en temps reel de la plage dynamique
WO2000079784A1 (fr) * 1999-06-04 2000-12-28 The Trustees Of Columbia University In The City Of New York Procede et dispositif d'imagerie a plage dynamique haute par utilisation d'expositions variant spatialement
EP0912043A3 (fr) * 1997-10-27 2001-02-07 Texas Instruments Incorporated Améliorations de/ou concernant les capteurs d'images
WO2003017643A1 (fr) * 2001-08-07 2003-02-27 Hrl Laboratories, Llc Conversion de signaux d'image avec augmentation de la precision et de la plage dynamique
US7142240B1 (en) * 2000-07-17 2006-11-28 Psion Teklogix Systems, Inc. Active pixel sensor array reset
US7701499B2 (en) 2004-12-07 2010-04-20 Bright Imaging Ltd. Method and apparatus for imaging of scenes having large intensity variance
US8610789B1 (en) 2000-02-23 2013-12-17 The Trustees Of Columbia University In The City Of New York Method and apparatus for obtaining high dynamic range images
US9100514B2 (en) 2009-10-28 2015-08-04 The Trustees Of Columbia University In The City Of New York Methods and systems for coded rolling shutter
EP2761657B1 (fr) * 2011-09-29 2019-10-02 Eye-Tech S.r.l. CAPTEUR ÉLECTRO-OPTIQUE avec une DYNAMIQUE LUMINEUSE VARIABLE

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4984002A (en) * 1989-01-12 1991-01-08 Sony Corporation Video camera shutter control by charge accumulation time of CCD images
US4985775A (en) * 1985-12-26 1991-01-15 Fuji Photo Film Co., Ltd. Electronic still camera system
US5117292A (en) * 1989-09-13 1992-05-26 Kabushiki Kaisha Toshiba Solid-state camera having changeable sensitivity
US5166779A (en) * 1991-09-18 1992-11-24 Videotek, Inc. Subcarrier to horizontal phase measurement and display for multiple video signals

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4985775A (en) * 1985-12-26 1991-01-15 Fuji Photo Film Co., Ltd. Electronic still camera system
US4984002A (en) * 1989-01-12 1991-01-08 Sony Corporation Video camera shutter control by charge accumulation time of CCD images
US5117292A (en) * 1989-09-13 1992-05-26 Kabushiki Kaisha Toshiba Solid-state camera having changeable sensitivity
US5166779A (en) * 1991-09-18 1992-11-24 Videotek, Inc. Subcarrier to horizontal phase measurement and display for multiple video signals

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5565915A (en) * 1993-06-15 1996-10-15 Matsushita Electric Industrial Co., Ltd. Solid-state image taking apparatus including photodiode and circuit for converting output signal of the photodiode into signal which varies with time at variation rate depending on intensity of light applied to the photodiode
EP0885456A4 (fr) * 1996-11-11 1998-12-23
EP0912043A3 (fr) * 1997-10-27 2001-02-07 Texas Instruments Incorporated Améliorations de/ou concernant les capteurs d'images
WO2000024190A1 (fr) * 1998-10-19 2000-04-27 Ben-Gurion University Of The Negev Imageur optique utilisant un procede d'expansion adaptative en temps reel de la plage dynamique
US6831689B2 (en) 1998-10-19 2004-12-14 Orly Yadid-Pecht Optical imager using a method for adaptive real-time expanding of the dynamic range
US7924321B2 (en) 1999-06-04 2011-04-12 The Trustees Of Columbia University In The City Of New York Apparatus and method for high dynamic range imaging using spatially varying exposures
WO2000079784A1 (fr) * 1999-06-04 2000-12-28 The Trustees Of Columbia University In The City Of New York Procede et dispositif d'imagerie a plage dynamique haute par utilisation d'expositions variant spatialement
US9363447B2 (en) 1999-06-04 2016-06-07 The Trustees Of Columbia University In The City Of New York Apparatus and method for high dynamic range imaging using spatially varying exposures
US8934029B2 (en) 1999-06-04 2015-01-13 The Trustees Of Columbia University In The City Of New York Apparatus and method for high dynamic range imaging using spatially varying exposures
US8610789B1 (en) 2000-02-23 2013-12-17 The Trustees Of Columbia University In The City Of New York Method and apparatus for obtaining high dynamic range images
US7929034B2 (en) 2000-07-17 2011-04-19 Harusaki Technologies, Llc Active pixel sensor array reset
US7142240B1 (en) * 2000-07-17 2006-11-28 Psion Teklogix Systems, Inc. Active pixel sensor array reset
US6720899B2 (en) 2001-08-07 2004-04-13 Hrl Laboratories, Llc Extended precision pixel
WO2003017643A1 (fr) * 2001-08-07 2003-02-27 Hrl Laboratories, Llc Conversion de signaux d'image avec augmentation de la precision et de la plage dynamique
US7701499B2 (en) 2004-12-07 2010-04-20 Bright Imaging Ltd. Method and apparatus for imaging of scenes having large intensity variance
US9100514B2 (en) 2009-10-28 2015-08-04 The Trustees Of Columbia University In The City Of New York Methods and systems for coded rolling shutter
US9736425B2 (en) 2009-10-28 2017-08-15 Sony Corporation Methods and systems for coded rolling shutter
EP2761657B1 (fr) * 2011-09-29 2019-10-02 Eye-Tech S.r.l. CAPTEUR ÉLECTRO-OPTIQUE avec une DYNAMIQUE LUMINEUSE VARIABLE

Also Published As

Publication number Publication date
IL100620A (en) 1994-11-11
AU3587493A (en) 1993-08-03

Similar Documents

Publication Publication Date Title
US6831689B2 (en) Optical imager using a method for adaptive real-time expanding of the dynamic range
US4614966A (en) Electronic still camera for generating long time exposure by adding results of multiple short time exposures
US4635126A (en) Image pick-up system
US6744471B1 (en) Electronic camera that synthesizes two images taken under different exposures
US7209169B2 (en) Imaging system using solid-state CMOS imaging device
KR100247936B1 (ko) 동화상 카메라 시스템에서 리드아웃 방법 및 그 장치
US4597014A (en) Solid-state image pickup device
EP0133586A1 (fr) Appareil et procédé pour produire un signal vidéo d'image stationnaire utilisant un dispositif d'image à corps solide
JP2002314873A (ja) 撮像装置用回路及び撮像用信号処理方法
WO1993014595A1 (fr) Procede et appareil d'augmentation de la gamme dynamique de capteurs optiques
US6141047A (en) Image signal processing apparatus and image pickup device
US5576762A (en) Solid-state image pickup device
JPH0250584A (ja) ダイナミックレンジ拡大システム
KR100430411B1 (ko) 디지털 카메라 및 이미지 처리를 위한 프로그램가능점증식 ａ/ｄ 변환기
US5512950A (en) Solid state imager device and driving method thereof
KR100341978B1 (ko) 비디오처리시스템및비디오이미지처리방법
JP2893687B2 (ja) 焦点検出装置
US5267015A (en) Photometric apparatus
JPH0556343A (ja) 電子的撮像装置
US5771411A (en) Photometry device and method
JPH0771237B2 (ja) 光電変換装置
JP2548705B2 (ja) 撮像装置
KR100248226B1 (ko) 화상독취기의 밝기조정방법 및 그 장치
JP2519202B2 (ja) 電子的撮像装置
KR0183808B1 (ko) Ccd 카메라의 전자 셔터 속도제어 시스템

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AT AU BB BG BR CA CH DE DK ES FI GB HU JP KP KR LK LU MG MN MW NL NO PL RO RU SD SE US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN ML MR SN TD TG

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
ENP Entry into the national phase

Ref country code: US

Ref document number: 1994 256383

Date of ref document: 19940708

Kind code of ref document: A

Format of ref document f/p: F

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: CA

点击 这是indexloc提供的php浏览器服务，不要输入任何密码和下载