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WO1997005538A1 - Correlateur optique et procede de correlation de signaux optiques - Google Patents

Correlateur optique et procede de correlation de signaux optiques Download PDF

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Publication number
WO1997005538A1
WO1997005538A1 PCT/DE1996/001184 DE9601184W WO9705538A1 WO 1997005538 A1 WO1997005538 A1 WO 1997005538A1 DE 9601184 W DE9601184 W DE 9601184W WO 9705538 A1 WO9705538 A1 WO 9705538A1
Authority
WO
WIPO (PCT)
Prior art keywords
radiation
spatially resolving
optical
resolving detector
unit
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.)
Ceased
Application number
PCT/DE1996/001184
Other languages
German (de)
English (en)
Inventor
Gerald SÖLKNER
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.)
Siemens AG
Siemens Corp
Original Assignee
Siemens AG
Siemens Corp
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 Siemens AG, Siemens Corp filed Critical Siemens AG
Publication of WO1997005538A1 publication Critical patent/WO1997005538A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06E—OPTICAL COMPUTING DEVICES; COMPUTING DEVICES USING OTHER RADIATIONS WITH SIMILAR PROPERTIES
    • G06E3/00—Devices not provided for in group G06E1/00, e.g. for processing analogue or hybrid data
    • G06E3/001—Analogue devices in which mathematical operations are carried out with the aid of optical or electro-optical elements
    • G06E3/005—Analogue devices in which mathematical operations are carried out with the aid of optical or electro-optical elements using electro-optical or opto-electronic means

Definitions

  • the rotation, the deformation of the surface and the speed of a body illuminated by a laser beam can be determined by analyzing the intensity fluctuations occurring in a speckle pattern.
  • these optical methods based on the speckle phenomenon have also been used in the field of medical diagnostics to measure the average flow velocity of the blood in the uppermost skin layers in vivo (see, for example, [1, 2]).
  • the laser radiation reflected by the illuminated tissue is detected using optical waveguides, the core diameter of which is approximately 100 ⁇ m. Therefore, typically less than 10 speckies are imaged on the photodetector and subjected to a frequency analysis, the mean fluctuation frequency of the measured photon current serving as a measure of the flow rate of the blood.
  • the aim of the invention is to create an optical correlator which can be used in particular as a detector 5. in a laser Doppler measuring device which investigates the properties of a strongly scattering medium.
  • the correlator should be able to detect several 1000 individual speckles and evaluate them in parallel.
  • a correlator with the features specified in claim 1 has this property. Further developments and refinements of the correlator are the subject of the dependent claims. Claims 9 and 10 relate to a corresponding method for correlating optical signals. 5
  • the mean flow velocity of the blood in near-surface tissue layers is measured by analyzing the intensity fluctuation which occurs in a speckle pattern and is caused by the movement of the 5 scattering centers (red blood cells).
  • the evaluation can be based on a suitable frequency filtering or, the equivalent, the Determination of the temporal correlation function is based (see [4]).
  • the detector shown schematically in the drawing is able to generate corresponding autocorrelation values for the speckle pattern fed to it via a glass fiber bundle 1 or a free-beam optics. On the object side, the glass fibers 2 lying on the skin are each exposed to radiation of the intensity I * 1D (t).
  • the optics arranged downstream of the glass fiber bundle 1 and consisting of an imaging lens system 3 and a beam splitter 4 have the task both on the spatially resolving detector 5 (detector which measures the intensity as a function of location) and on the following as a light modulator ( Spatial-Light-Modulator) designated unit 6 to generate an intensity distribution corresponding to the speckle pattern.
  • the light modulator 6 has a matrix of areas or pixels M 1D , the transmission of which can be controlled individually.
  • liquid crystals are usually used as optical switching elements, the number of electrically addressable areas Mj being dependent on the model and manufacturer.
  • the number of glass fibers 2 in the fiber bundle 1 should correspond to the number N of pixels Mij.
  • the lens system 3 then forms each Faser ⁇ end to exactly one pixel of the light modulator 6 H 13, so that there in each case laser radiation of intensity I ⁇ : incident (t).
  • the location-resolving detector 5 consists of a multichannel plate 51 and a charge carrier shifting unit 52, hereinafter referred to as CCD (charge-coupled device), the number of channels serving for the multiplication of photoelectrons K 1D corresponds to the number of glass fibers 2 and thus the number N of pixels - of light modulator 6.
  • CCD charge carrier shifting unit
  • Each of the channels K 13 exposed to radiation ar intensity I_ 3 (t) is assigned a plurality of pixels of the CCD 52, since this usually has up to 1024 x 1024 radiation-sensitive areas.
  • the output signals of the CCD 52 representing the respective measured intensities I 13 (t) are fed to the electronic delay unit 7, there delayed by a predetermined time period ⁇ of typically 25 ⁇ s ⁇ ⁇ 10 ms and read into the computer 8.
  • This controls the light modulator 6 in such a way that the transmission of an area M. at the time t of the intensity I. j (t - ⁇ ) measured in the assigned pixel area S ⁇ : of the spatially resolving detector 5 at the time t ': t - ⁇ corresponds.
  • the intensity I c ⁇ ; ⁇ of the radiation transmitted by an area M 1D is then in each case through
  • I C 1D I l3 (t - ⁇ ) x I 13 (t)
  • the output signal of the area S ' 1D assigned to the pixel M ⁇ : of the spatially resolving detector 9 then represents the through

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Nonlinear Science (AREA)
  • Optics & Photonics (AREA)
  • General Physics & Mathematics (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

Corrélateur optique et procédé de corrélation de signaux optiques. On peut mesurer la vitesse moyenne d'écoulement du sang dans les couches proches de la surface de tissus en analysant les variations de l'intensité causées par le déplacement des globules rouges et exprimées en un motif de tachetures. Il faut à cet effet des corrélateurs optiques qui puissent détecter en même temps et évaluer en parallèle plusieurs milliers de tachetures individuelles. Le corrélateur décrit comprend une optique (3, 4) qui reproduit le motif de tachetures à analyser sur une unité de détection/modulation de lumière (6, 9) et sur un détecteur pourvu de zones sensibles aux rayonnements Sij. Un ordinateur (8) qui reçoit les signaux de sortie du détecteur (5) retardés chacun d'un interval de temps τ commande le modulateur de lumière (6) de sorte que la transmission d'une zone du modulateur Mij au moment t dépende de l'intensité Iij mesurée dans la zone associée du détecteur Sij (t* = t - τ). Le détecteur (9) connecté en aval du modulateur de lumière (6) génère alors un signal de sortie proportionnel à la fonction d'autocorrélation de la tacheture reproduite sur Mij. L'invention trouve des applications dans des appareils laser Doppler de mesure et des appareils de mesure de l'irrigation sanguine.
PCT/DE1996/001184 1995-07-27 1996-07-03 Correlateur optique et procede de correlation de signaux optiques Ceased WO1997005538A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19527540.3 1995-07-27
DE1995127540 DE19527540C2 (de) 1995-07-27 1995-07-27 Optischer Korrelator und Verfahren zur Korrelation optischer Signale

Publications (1)

Publication Number Publication Date
WO1997005538A1 true WO1997005538A1 (fr) 1997-02-13

Family

ID=7767974

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1996/001184 Ceased WO1997005538A1 (fr) 1995-07-27 1996-07-03 Correlateur optique et procede de correlation de signaux optiques

Country Status (2)

Country Link
DE (1) DE19527540C2 (fr)
WO (1) WO1997005538A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2170945C1 (ru) * 1999-12-21 2001-07-20 Ростовский военный институт ракетных войск Оптический триггер
US7926945B2 (en) 2005-07-22 2011-04-19 Carl Zeiss Meditec Ag Device and method for monitoring, documenting and/or diagnosing the fundus

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105319386B (zh) * 2015-05-06 2019-01-25 中北大学 一种基于调制激光的主动式测速方法及测速装置
CN105380638B (zh) * 2015-12-15 2019-02-26 黄恺 一种用于激光散斑血流速度的定量成像装置及其方法

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0174581A2 (fr) * 1984-09-04 1986-03-19 Fondazione Pro Juventute Don Carlo Gnocchi Corrélateur optique pour l'acquisition des coordonnées des objets dans les systèmes de traitement en temps réel des images

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2538456B2 (ja) * 1991-08-12 1996-09-25 浜松ホトニクス株式会社 光学的変位量測定装置

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0174581A2 (fr) * 1984-09-04 1986-03-19 Fondazione Pro Juventute Don Carlo Gnocchi Corrélateur optique pour l'acquisition des coordonnées des objets dans les systèmes de traitement en temps réel des images

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
WEEKS A R ET AL: "NONLINEAR IMAGE TRANSFORMATIONS IMPLEMENTED WITH SPATIAL LIGHT MODULATORS", OPTICAL ENGINEERING, vol. 33, no. 3, 1 March 1994 (1994-03-01), pages 850 - 855, XP000434955 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2170945C1 (ru) * 1999-12-21 2001-07-20 Ростовский военный институт ракетных войск Оптический триггер
US7926945B2 (en) 2005-07-22 2011-04-19 Carl Zeiss Meditec Ag Device and method for monitoring, documenting and/or diagnosing the fundus

Also Published As

Publication number Publication date
DE19527540C2 (de) 1998-09-10
DE19527540A1 (de) 1997-01-30

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