EP1698166A1 - Antiblendeinrichtung, verfahren und hilfseinrichtung und abbildungssystem mit verbesserter helligkeitsdynamik - Google Patents

Antiblendeinrichtung, verfahren und hilfseinrichtung und abbildungssystem mit verbesserter helligkeitsdynamik

Info

Publication number
EP1698166A1
EP1698166A1 EP04817602A EP04817602A EP1698166A1 EP 1698166 A1 EP1698166 A1 EP 1698166A1 EP 04817602 A EP04817602 A EP 04817602A EP 04817602 A EP04817602 A EP 04817602A EP 1698166 A1 EP1698166 A1 EP 1698166A1
Authority
EP
European Patent Office
Prior art keywords
image
filter
camera
acquisition
equipment according
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Withdrawn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
EP04817602A
Other languages
English (en)
French (fr)
Inventor
Jean-Loup Chretien
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.)
Tietronix Optics SAS
Original Assignee
Tietronix Optics SAS
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 Tietronix Optics SAS filed Critical Tietronix Optics SAS
Publication of EP1698166A1 publication Critical patent/EP1698166A1/de
Withdrawn legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/80Camera processing pipelines; Components thereof
    • H04N23/81Camera processing pipelines; Components thereof for suppressing or minimising disturbance in the image signal generation
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/70Circuitry for compensating brightness variation in the scene
    • H04N23/75Circuitry for compensating brightness variation in the scene by influencing optical camera components

Definitions

  • the present invention relates to equipment and a method for modulating an image received by an image sensor in order to avoid dazzling ent by intense sources and to increase the light dynamics.
  • Such equipment can constitute active sun visors for automobiles, boats or aircraft, or improved observation means, in night vision or in security.
  • the method can also be implemented to improve cinematographic or photographic equipment.
  • US patent application US020071185 is known in the state of the art. This patent describes a dynamic optical filtering system and method which blocks intense light sources without altering the rest of the scene.
  • a sensor measures the intensity and position of the light so that the selected cells of a filter matrix mask the intense light source (s).
  • the incident image passes through a beam splitter transmitting a part to said sensor, and the other part to a shooting camera placed behind the filter matrix.
  • the patent US4918534 relates to equipment intended for medical imaging for scenes corresponding to the taken over by an image intensifier. This document does not disclose the characteristic relating to the position of the optical filter in the focal plane.
  • This prior art solution involves the use of a sensor for the analysis of the unprocessed image, and a camera for the acquisition of the image processed by the filter. The beam splitter reduces the brightness of the image acquired by the camera.
  • the object of the invention is to propose a technical solution overcoming these drawbacks, in order to allow the production of more compact and less expensive equipment, having superior optical qualities.
  • the invention relates, in its most general sense, to anti-glare equipment comprising an image sensor, a display means for rendering the image and an adaptive light modulator having a filtering modulation controlled by said image sensor, said modulation having masking zones obscuring or attenuating the glare zones characterized in that it comprises a single image sensor ensuring both the analysis function for the control of the light modulator adaptive and modulated image recording function.
  • image sensor means a means of acquiring an image in the light spectrum, and delivering an electrical signal. It is notably and not exclusively a CCD charge transfer sensor, a matrix of micro-bolometers, a cathode-ray tube camera, a charge multiplication sensor.
  • the term “light modulator” is understood to mean means having variable transmission or reflection zones and controlled by an electrical signal, which is interposed in the field of vision of the image sensor. This is for example a liquid crystal screen or a network of MEMS type micromirrors.
  • the expression “transmission rate” of the light modulator is understood to mean the fraction of the light that it transmits to the image sensor, whatever its type of modulation (transmissive, reflective, transflective, etc. ).
  • the maximum transmission rate of the modulator (“white”) is called Vtmax.
  • the minimum transmission rate of the modulator (“black”) Vtmin.
  • Vtmax / Vtmin c with c> l.
  • the term “analysis mode” means the situation where the electrical signal delivered by the image sensor is intended to be used for the generation of the modulation signal controlling the light modulator.
  • “recording mode” means the situation where the electrical signal delivered by the image sensor is intended to be used for the generation of the signal to the display means, for recording or the restitution of a modulated image, for example on a video monitor, a projection screen ...
  • the output of the image sensor is connected to an electronic circuit controlling the modulator alternately for a modulation for analysis purposes and for a modulation for filtering purposes calculated as a function of the image viewed. by the image sensor during the previous analysis phase and active during the recording phase.
  • the circuit inhibits the transmission of the electrical signal from the image sensor to the display means during the analysis phases.
  • the electronic circuit transmits to the display means, during the analysis phases, a prerecorded image corresponding to the image transmitted by the image sensor before the analysis phase.
  • the electronic circuit controls the light modulator during the analysis phase, so that it has a uniform transmission rate over the entire surface, with a transmission value corresponding to a value Vt less than 1.
  • the light modulator is a liquid crystal filter.
  • said light modulator is a reflection filter.
  • said light modulator is a transmission filter.
  • said light modulator is placed in the focal plane of an input objective.
  • the light modulator is a filter with adjustable micromirrors.
  • the light modulator has a maximum and uniform transmission rate over the entire surface in a band of wavelengths.
  • said wavelength band corresponds to red.
  • the light modulator has an adjustable transmission rate in a band of wavelengths.
  • said band of wavelengths is the band 750 nm - 1400 nm.
  • the invention also relates to a method for processing an image acquired by an image sensor, comprising a step of filtering by a light modulator controlled by a periodically masking image. re-evaluated, characterized in that it includes an alternation of an image acquisition step and of analysis of said image to prepare a masking image, and a filtering step during which the image is acquired by the sensor image after interposition of said light modulator controlled by the previously reassessed masking image, the image acquisition steps for controlling the light modulator and for restoring the corrected image being carried out by the same sensor d 'picture.
  • the images restored during the analysis step correspond to a previous corrected image.
  • the analysis step is carried out in a time less than the duration of the retinal persistence.
  • the invention also relates to an accessory of a photographic or video recording device, for the correction of the image acquired by an image sensor characterized in that it comprises an active light modulator controlled by an image of filtering periodically re-evaluated by a circuit receiving the image acquired by the image sensor and periodically controlling the presentation by the light modulator of a reference filtering image during the analysis phases.
  • the circuit also inhibits the connection between the image sensor and the output of the shooting device during the analysis phases.
  • FIG. 1 represents the optical diagram of an equipment according to the invention
  • - Figure 2 represents a view of an alternative embodiment
  • - Figure 3 shows the general architecture of an equipment according to the invention
  • - Figure 4 shows a schematic view of a modulator implemented by the invention
  • - Figure 5 shows the block diagram of the electronic circuit
  • - Figure 6 represents the block diagram of the filtering module
  • - Figure 7 represents the response curve of the filtering function
  • - Figures 8 and 9 represent the thresholding table and the corresponding response curve
  • Figure 10 represents the equipment operating algorithm
  • - Figures 11 and 12 represent the thresholding table and the corresponding response curve for a variant with several threshold levels.
  • the equipment according to the invention comprises an image sensor (1), for example the sensor of a digital video camera or of a digital photographic camera.
  • An adaptive light modulator (2) is interposed on the optical path. It is placed in the image plane of an input objective (3) focusing the image observed in the plane of the light modulator (2).
  • An output optic (4) is arranged between the light modulator (2) and the optics of the camera. It is of course possible to combine in a single optical unit the output optics (4) and the optics of the shooting device.
  • a computer (5) is connected to the output of the image sensor (1). It controls the adaptive light modulator (2) as well as the video output of the equipment. In the example described, it includes a video memory.
  • This calculator periodically performs the following functions: 1 - Analysis: during this step, the computer (5) controls the light modulator (2) for the formation of a reference masking image, for example a filtering image having a uniform filtering rate over the entire surface of the light modulator, to achieve a uniform gray filter.
  • This uniform filtering rate can be variable, and literally translated by a color, going from white (zero filtering or maximum transmission) to black (maximum filtering or minimum transmission).
  • the output of the image sensor (1) delivers an image whose level of brightness is reduced overall.
  • 2 - Evaluation of a new masking image During this step, the computer determines the high intensity zones to calculate a new masking image. Areas whose brightness exceeds a threshold value will be completely or partially hidden.
  • the computer (5) sends to the light modulator (2) a re-evaluated filtering image, and the light modulator has a configuration completely or partially obscuring the high intensity zones.
  • the image acquired by the sensor (1) is transmitted to the video output for viewing a processed image.
  • the image available on the video output can consist of an image recorded in a video memory (6), corresponding to the previous processed image.
  • the duration of stages 1 and 2 is less than the retinal persistence time.
  • the cycle is preferably carried out with a frequency greater than 25 treatments per second.
  • the reference image controlling the light modulator during step 1 is a transmission image constant, the level of which can possibly be adjusted by analysis of the intensities of the images of the preceding cycles.
  • This variant makes it possible to optimize the level of brightness of the images during steps 1 and 2, and to improve the thresholding performance. It is also possible to provide non-uniform reference images, having a lower transmission rate in the zones having a probability of over-luminosity determined from the information available on the previous images. In this case, the calculation of the masking image will take into account the profile of the reference image for the calculation of the new masking image.
  • FIG. 2 represents a view of the optical diagram of an alternative embodiment using a reflection light modulator and not a transmission light modulator.
  • the light modulator (12) consists of micromirrors, the orientation of which is controlled between a position of reflection towards the image sensor and a position of dispersion or reflection towards a light trap.
  • the micromirrors corresponding to the areas of high light intensity are controlled to scatter the incident beam or direct it towards a light trap, while the other micromirrors are oriented to reflect the incident beam towards the image sensor.
  • FIG. 3 represents the general architecture of an item of equipment according to the invention.
  • the equipment conventionally comprises an input optic (19) forming an image in the focal plane of a light modulator (20) and an image sensor (21) controlled by an electronic control circuit (23).
  • the control circuit (23) controls the operation of the light modulator (20) as well as the image sensor (21) and delivers the video signal intended for the display means.
  • the control circuit (23) provides the match between the light modulator and the image sensor, which are generally in matrix form. The optical agreement between the two ensures a correspondence between a group of pixels Mi of the light modulator and a group of pixels Ci of the image sensor.
  • the light modulator has a resolution of 960 x 720
  • the image sensor has a resolution of 640 x 480 (VGA).
  • This light modulator is divided into pixel groups formed by 3 x 3 pixels, ie 320 x 240 pixel groups Mi (i varies from 1 to 76800) as shown diagrammatically in FIG. 4.
  • This image sensor is divided into as many pixel groups Ci in optical correspondence with the pixel groups Mi of the light modulator (ie Ci formed by 2 x 2 pixels).
  • Gi varies from the value Vtmin / Vtmax when it is a question of the level of "black”, to 1 when it is a question of the level of "white”. Gi therefore varies from 1 / c to 1.
  • the transmission rate Vti of the pixel group Mi of the light modulator depends in particular on the transmission rates of each of the pixels making up the group.
  • Vti is manufactured by uniformly adjusting all the pixels of Mi.
  • Mi is composed of 3 x 3 pixels.
  • Vti is produced by setting the central pixel to Vtmax and the other 8 pixels to the same value allowing the result on the 9 pixels to be Vti, as shown schematically in Figure 4.
  • the light modulator consists of a matrix of micromirrors. Using a matrix of micromirrors as a light modulator has several advantages: - Vtmax is important. - it is important. - The modulation times are fast. The Gi's can be adjusted using time modulation rates (duty cycles).
  • the control of the modulator can be carried out according to two operating modes.
  • the first operating mode the device operates alternately in “analysis mode” and in “recording mode”.
  • the second operating mode the "analysis mode” is carried out at the same time as the "recording mode”.
  • a cycle comprises a period containing an analysis phase followed by a recording phase.
  • the recording mode being the effective mode, this is of a longer duration than the analysis mode.
  • the heart of the device is the electronic intelligence circuit (22) which synchronizes the different elements and which manages all the signals according to the mode (analysis or recording).
  • Tobtuan Tobtuenreg x Tan with Tan smaller than 1.
  • Gan x Tan 1 / c.
  • Tan realization 1/10.
  • Step 3 The electronic circuit acquires the signal from the image sensor. It processes this information with an operating algorithm and the other parameters in its possession (including the control parameters with which it is controlling the light modulator and the image sensor). The result of this processing will be used during the next recording phase.
  • Step 4 The electronic circuit informs that the current mode is the analysis mode and does not transmit information from the image sensor.
  • Step 5 The signal transmitted to the display means is a reproduction of the signal transmitted to the display means at the end of the previous recording phase.
  • Step 1 The electronic circuit commands the light modulator to present a filtering modulation calculated during the processing of signals "3" from the previous analysis phase.
  • Step 2 The electronic circuit controls the parameters of the image sensor (shutter time, gain, ). These parameters are calculated during the processing of the signals of step 3 of the previous analysis phase.
  • Step 3 The electronic circuit acquires the signal from the image sensor.
  • Step 4 The electronic circuit transmits the signal from the image sensor as well as the values of the control parameters with which it is controlling the light modulator and the image sensor.
  • Step 5 The signal transmitted to the display means is produced from the signal data of step 4.
  • Example of processing within the electronic circuit link between Gi in recording mode and Yi in analysis mode
  • the filtering modulation during a recording phase is a function in particular of the image sensor signal from the previous analysis phase. This means that Gi during a recording phase is in particular a function of Yi of the previous analysis phase.
  • It can be a unique look-up table registered in the electronic circuit, or configurable by the user, or chosen by the electronic circuit (within a catalog of tables stored in its memory) according to parameters.
  • the useful information can relate to only one group of pixels; it is therefore only necessary to acquire a single datum per group of pixels.
  • One such example is the use of the image sensor in “bining” mode (averaging of several neighboring pixels towards a single output data).
  • FIG. 5 represents the simplified architecture diagram of electronic intelligence: it comprises a multiplexer (30) receiving data from a memory (31) containing the recording control parameters, and from a memory (32) containing the analysis command parameters (Tan, ). It also includes a synchronization machine (33) delivering data to a second multiplexer (34). A third multiplexer (35) receives data from a filter circuit (36) and from the Gan modulator (37). A synchronization machine is synchronized with the image sensor (master or slave). It routes the signals according to the mode (analysis or recording).
  • a multiplexer (34) defines a uniform transmission rate for the "Gan” modulator (37).
  • a multiplexer defines the parameters for controlling the image sensor of the analysis mode (Tan, ).
  • the signals Yi are routed by a multiplexer to a memory M1. They are then processed with the filter transfer function (see 2.2).
  • a multiplexer defines the filter modulation from the processing resulting from the filter transfer function (36).
  • a multiplexer defines the parameters for controlling the image sensor of the recording mode.
  • the signals Yi are routed by a multiplexer to a memory M2 where they are stored destined for the electronics for the display means.
  • all the groups of pixels Mi of the modulator are managed identically.
  • the pixels are managed differently. For example, all pixels can be set to Vtmin except one pixel set between Vtmin and Vtmax.
  • a light modulator is controlled according to information from the own image sensor that it protects from glare.
  • the principle being a permanently active servo with a feedback.
  • electronic intelligence determines the filtering modulation through an analysis phase.
  • FIG. 6 represents the block diagram of the filtering module corresponding to this second mode of operation.
  • the filtering modulation is determined based on the modulation applied to the previous cycle and the information seen by the retina also in the previous cycle.
  • FIG. 7 represents the response curve of the filtering function.
  • the threshold SI is determined according to the photometric characteristics sought.
  • Figures 8 and 9 show the threshold table and the corresponding response curve for several filtering levels determined by different threshold levels.
  • Figure 10 shows the equipment operating algorithm.
  • the modulator is completely transparent, all the pixels are in on mode.
  • This processing is carried out for each of the pixels, which leads to a permanent recalculation of the filtering carried out by the modulator, during the acquisition of the images.
  • This filtering can be carried out by reference to several threshold values, as shown diagrammatically in FIGS. 11 and 12 corresponding to the thresholding table and to the response curve.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Studio Devices (AREA)
  • Blocking Light For Cameras (AREA)
  • Image Processing (AREA)
EP04817602A 2003-12-26 2004-12-27 Antiblendeinrichtung, verfahren und hilfseinrichtung und abbildungssystem mit verbesserter helligkeitsdynamik Withdrawn EP1698166A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0315467A FR2864740B1 (fr) 2003-12-26 2003-12-26 Equipement, procede et accessoire anti-eblouissement.
PCT/FR2004/003390 WO2005069605A1 (fr) 2003-12-26 2004-12-27 Equipement, procede et accessoire anti-eblouissement, systeme d’imagerie à dynamique lumineuse augmentee

Publications (1)

Publication Number Publication Date
EP1698166A1 true EP1698166A1 (de) 2006-09-06

Family

ID=34639640

Family Applications (1)

Application Number Title Priority Date Filing Date
EP04817602A Withdrawn EP1698166A1 (de) 2003-12-26 2004-12-27 Antiblendeinrichtung, verfahren und hilfseinrichtung und abbildungssystem mit verbesserter helligkeitsdynamik

Country Status (7)

Country Link
US (1) US20090015682A1 (de)
EP (1) EP1698166A1 (de)
JP (1) JP2007517443A (de)
CN (1) CN1902907A (de)
FR (1) FR2864740B1 (de)
IL (1) IL176143A0 (de)
WO (1) WO2005069605A1 (de)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2898234B1 (fr) * 2006-03-06 2008-06-13 Tietronix Optics Soc Par Actio Procede et dispositif d'elaboration d'images non saturees par une camera a transfert de charge ou equivalente
BR112012005139A2 (pt) * 2009-09-11 2019-09-24 Koninl Philips Electronics Nv sistema de iluminação e método para iluminar um objeto
DE102012217093A1 (de) * 2012-09-21 2014-04-17 Robert Bosch Gmbh Kamerasystem, insbesondere für ein Fahrzeug, und Verfahren zum Ermitteln von Bildinformationen eines Erfassungsbereichs
EP2797310B1 (de) * 2013-04-25 2018-05-30 Axis AB Verfahren, Linsenanordnung, Kamera, System und Verwendung zur Verminderung von Streulicht
CN109842767B (zh) 2019-01-09 2020-07-14 上海芯仑光电科技有限公司 一种防闪光电路组件及图像传感器
CN112597836B (zh) * 2020-12-11 2023-07-07 昆明理工大学 一种太阳低振幅振荡信号的放大方法

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US4918534A (en) * 1988-04-22 1990-04-17 The University Of Chicago Optical image processing method and system to perform unsharp masking on images detected by an I.I./TV system
US5483280A (en) * 1992-03-11 1996-01-09 Sony Corporation Arrangement for controlling an iris to regulate light in an optical system
FR2732849B1 (fr) * 1995-04-07 1997-06-20 Valeo Vision Dispositif a camera infrarouge pour systeme d'aide a la vision dans un vehicule automobile, et systeme l'incorporant
US5986705A (en) * 1997-02-18 1999-11-16 Matsushita Electric Industrial Co., Ltd. Exposure control system controlling a solid state image sensing device
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WO2003038516A1 (fr) * 2001-10-12 2003-05-08 Canon Kabushiki Kaisha Dispositif de regulation de la quantite de lumiere et systeme optique comprenant ce dispositif, ainsi que dispositif de prises de vues

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Also Published As

Publication number Publication date
FR2864740B1 (fr) 2006-05-05
WO2005069605A1 (fr) 2005-07-28
CN1902907A (zh) 2007-01-24
IL176143A0 (en) 2006-10-05
FR2864740A1 (fr) 2005-07-01
US20090015682A1 (en) 2009-01-15
JP2007517443A (ja) 2007-06-28

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