EP1393113A2 - Dispositif de determination d'un profil d'intensite et de couleur et/ou de nettete de systemes de lentilles optiques - Google Patents

Dispositif de determination d'un profil d'intensite et de couleur et/ou de nettete de systemes de lentilles optiques

Info

Publication number
EP1393113A2
EP1393113A2 EP02738120A EP02738120A EP1393113A2 EP 1393113 A2 EP1393113 A2 EP 1393113A2 EP 02738120 A EP02738120 A EP 02738120A EP 02738120 A EP02738120 A EP 02738120A EP 1393113 A2 EP1393113 A2 EP 1393113A2
Authority
EP
European Patent Office
Prior art keywords
sharpness
measuring
color
intensity
profile
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Withdrawn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
EP02738120A
Other languages
German (de)
English (en)
Inventor
Wilfried Donner
Christian WÖHLER
Detlef Grosspietsch
Sebastian SCHRÖDER
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.)
SCHROEDER, SEBASTIAN
Original Assignee
Donner Wilfried
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
Priority claimed from DE10126546A external-priority patent/DE10126546A1/de
Priority claimed from DE20111617U external-priority patent/DE20111617U1/de
Application filed by Donner Wilfried filed Critical Donner Wilfried
Publication of EP1393113A2 publication Critical patent/EP1393113A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
    • G01M11/02—Testing optical properties
    • G01M11/0242—Testing optical properties by measuring geometrical properties or aberrations
    • G01M11/0257—Testing optical properties by measuring geometrical properties or aberrations by analyzing the image formed by the object to be tested
    • G01M11/0264—Testing optical properties by measuring geometrical properties or aberrations by analyzing the image formed by the object to be tested by using targets or reference patterns
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
    • G01M11/02—Testing optical properties
    • G01M11/0285—Testing optical properties by measuring material or chromatic transmission properties
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
    • G02B7/28—Systems for automatic generation of focusing signals
    • G02B7/36—Systems for automatic generation of focusing signals using image sharpness techniques, e.g. image processing techniques for generating autofocus signals
    • G02B7/365—Systems for automatic generation of focusing signals using image sharpness techniques, e.g. image processing techniques for generating autofocus signals by analysis of the spatial frequency components of the image

Definitions

  • the invention relates to an apparatus and a method for determining a location-dependent intensity and color profile and / or sharpness profile and / or distortion profile of optical lens systems with a test image and an optical measuring field array.
  • a conventional device comprises a test pattern, e.g. B. a television test image, the test image comprising individual measuring fields, each of which is only suitable for assessing sharpness, color or intensity, distributed over the test image and relatively large.
  • a test pattern e.g. B. a television test image
  • the test image comprising individual measuring fields, each of which is only suitable for assessing sharpness, color or intensity, distributed over the test image and relatively large.
  • test image consists of large individual measuring fields, which are each only suitable for assessing sharpness, color or intensity.
  • the object of the invention is to provide a device and a method which provide a complete quality assessment of an image field of a lens system and thereby provide correction data for electronic image improvement, which are to be provided on a data carrier or in a processor for image processing. This object is achieved according to the invention by the device of claim 1.
  • Data carriers with stored test image data and those with correction data that are generated with the device are further protected objects.
  • a sharpness index is determined by analyzing the distribution of the gray values in the measurement field.
  • the line structures in a test pattern e.g. that shown in FIG. 2, which are projected onto the sensor field, produce a high variance of the gray values with high image sharpness and a small variance with low sharpness.
  • a unimodal distribution function is advantageously adapted to the distribution of the gray values, which has at least one parameter each that characterizes the maximum of the distribution and at least one parameter that characterizes the width of the distribution.
  • a Gaussian function with the parameters mean value and variance of the Gray values are used for the gray value measurement signals of the line structures.
  • a multimodal distribution function is adapted to the respectively measured gray value distribution, which is particularly advantageous if it has several maxima.
  • a distribution function is adapted to each maximum, which has at least one parameter that characterizes the mean value of the maximum and at least one parameter that characterizes the width of the maximum.
  • a total of several Gaussian functions is obtained, each of which describes a mean and a variance; see. "Mixture of Gaussians", CM. Bishop, Neural Networks of Pattern Recognition; Clarendon Press, Oxfor, 1995.
  • a low variance corresponds to a high sharpness and a large variance to a low sharpness.
  • Fig. 1 shows a device with a lens system
  • Test image and an image of the test image on a sensor field to which an evaluation device is connected are provided.
  • Fig. 3 shows a measuring field of the test image.
  • a device according to the invention in FIG. 1 comprises a test image 1, which is imaged on a sensor field 6 by means of an optical lens system 3 to be measured.
  • the test image 1 can be displayed on a monitor or a photo.
  • the test image is imaged with the optical lens system 3, the profile (s) of which is to be created, with a certain aperture setting, uniform illumination of the test image and a plane-parallel arrangement of the camera with the test image on a specific imaging scale.
  • Figure 6 can be taken directly from the sensor field of an electronic camera or fed to a scanner as a photo.
  • the electronic image signals of the camera or the scanner are fed to a computer 60, which uses suitable programs to determine the distribution of the sharpness, the intensity and the colors of the test patterns distributed over the grid via the illustration 6.
  • These distributions are structured in profiles, which are transferred to an image processing system 62 either immediately or after temporary storage on a data carrier 61
  • the image processing system 62 can be located in a camera which is equipped with the lens system 3 itself or with the same lens system. However, images B from such a camera or via a scanner can also be recorded in the processing system 62, to which the profiles are fed, and which creates corrected image data, which have been corrected from the image errors, and which are output as a corrected image KB to a printer P. This enables corrected, high-quality images to be generated in cameras with simple lens systems.
  • the sensor means of the image of the test image must have a suitably large resolution of intensity and lines or areas (pixels) so that the test patterns shown are each completely resolved.
  • the test image in FIG. 2 has several identical measurement fields, which are only partially completed in the image, and which are preferably arranged periodically in both dimensions on a test image.
  • Each measuring field comprises measuring cells, which are shown in detail in FIG. 3, by means of which the intensity, color and sharpness in the area of each individual measuring field can be measured (so-called color, intensity and sharpness measuring cells).
  • the intensity, color and sharpness can thus be measured in the respective measuring cell of the measuring field for each area of the distributed measuring fields 5, whereby the accuracy of the intensity and color profiles and / or sharpness profiles created depends directly on the size of the measuring field.
  • the typical imaging systems represent all colors visible to humans. This is usually achieved by the three primary colors, i.e. the basis of the color space, typically red, yellow and blue, are mixed in different intensities. In general, however, it is possible to choose any base of the color space visible to humans. By choosing different intensities of the respective primary colors, i.e. different color values in the color space, it is possible to display all colors visible to humans.
  • the measuring field comprises measuring cells which are each filled with a basic color. In order to adapt the test image to most known imaging systems, the colors red, green and blue are preferably used as the primary colors.
  • the measuring field also includes gray measuring cells in order to be able to determine location-dependent discoloration of the lens system.
  • the measuring field comprises measuring cells which are each filled with a line pattern of different line density.
  • the line patterns of adjacent measuring cells preferably have a different one Orientation on.
  • the measuring field comprises an edge transition, in the present case a black and white edge transition.
  • the respective measuring cells are expediently completely filled with the respective object to be measured, i.e. the "blue" measuring cell is expediently completely filled with blue, for example.
  • the device with the test pattern which has measuring fields, which are preferably arranged periodically in both dimensions of the test pattern, and each measuring field has different measuring cells (intensity and color and / or sharpness measuring cells), and with an optical lens system and a device for measuring the color values and determination of the sharpness, in particular a CCD camera with a connected computer or a scanner with a computer for scanning a test image projection of the lens system, is used to carry out a method for determining a location-dependent intensity and color profile and / or sharpness profile of the optical lens system.
  • the positions of all measurement fields in the display of the test image are determined.
  • the sharpness profile is created as follows: First, a measuring cell with maximum sharpness is determined in a partial step, in a further partial step parameter P j (x ⁇ , y ⁇ , by the sharpness measurement number S j (X, yj . ) to approach each measuring cell to that of the reference cell for sharpness, and in a third sub-step creates a continuous sharpness profile by interpolation between the sharpness measuring cells.
  • a number of primary colors are imaged by the optical lens system in a first sub-step, in a second sub-step for each intensity and color measuring cell the representation of the test image is the respective intensity - And color value measured in the respective color space, the measuring cell with the maximum color or intensity value being used as a reference cell in a third sub-step, in a fourth sub-step a correction factor for each measuring field and the intensity is calculated, based on the respective reference value, and in a fifth sub-step a complete intensity and color profile is created by interpolation between the intensity or color measuring cell results.
  • This method can also be used separately for each color plane and separately for radial or tangential image structures.
  • the step of creating the intensity and color profile and that of creating a sharpness profile can be carried out separately from one another and are therefore fundamentally interchangeable. It is therefore not mandatory to create both profiles or one profile in front of the other.
  • the position of all measuring fields in the representation of the test image is determined with an undistorted representation of the test image.
  • at least three points are used in the representation, which correspond to known positions in the template, in order to calculate the orientation and the magnification of the representation.
  • the position of all intensity and color and / or sharpness measuring cells in the display of the test image is thus known.
  • a distortion in the representation of the test image such as can occur due to a defective lens or near the edge of the lens, a distortion coefficient must be determined with which the distortion can be calculated from the representation.
  • the distortion coefficient is calculated on the basis of points in the representation which correspond to known positions in the test image. In general, it can be assumed that the distortion coefficient is not constant for all positions of the test pattern.
  • the measuring field with maximum sharpness is first determined in the second step.
  • This measuring field can be determined on the one hand by visual impression, i.e. by the user himself, and on the other hand with the help of an automatic procedure.
  • a sharpness index is determined for each measuring field Measuring field with the largest measure of sharpness is used as a reference field for sharpness.
  • the reference field is intended for sharpness
  • a computational method is required to increase the sharpness of an image or to approximate the sharpness measurements of all measuring fields to that of the reference field of sharpness.
  • these methods can also be used to determine a sharpness measurement number, in particular if the reference field for sharpness was determined by visual impression.
  • the parameters P j to be varied in the method which, after variation thereof, give the best approximation of the sharpness measurement number of the measuring field to the sharpness measurement number of the reference field for sharpness, are themselves considered to be a sharpness measurement number.
  • the frequency spectrum of the respective measuring field is matched to that of the reference field, with those parameters which provide the best match serve as a sharpness index.
  • a method for unsharp masking which implicitly likewise uses a correction function K (f) in the spatial frequency space can be used as the computational method for increasing the image sharpness.
  • K (f) the correction function
  • the radius of the mask and the intensity are generally used as parameters.
  • the quantities determined so far are discrete, ie they relate to a specific measuring field. Interpolation is necessary to achieve a continuous profile. This can be achieved, for example, in the third step by interpolating the parameters P j (x ⁇ , y) to parameters P j (x, y) or in the second step of the third step by bilinear or bicubic interpolation.
  • the intensity and color profiles and / or sharpness profiles created are used to improve the quality of representations created with the same or a same optical lens system.
  • this can be done, for example, by storing the profiles for this camera in the camera and improving the image using the profiles, preferably automatically.
  • the profiles can also be stored in a postprocessor in order to save storage space in the camera, and the images can be improved, preferably automatically, when downloading from the camera using the profiles.
  • profiles can also be used to improve scanned images.
  • the digital image present in the computer is improved with the profiles which are assigned to the lens system with which the representation was created.
  • the profiles required for this can be stored on any data carrier.
  • Line patterns are arranged in two lines, each with a line number increasing by a factor of 1: 1.5 with a correspondingly decreasing line width.
  • the lines in the measuring cells 27, 29, 31 are alternately oriented horizontally and vertically, and in the second line in the measuring cells 33, 35, 37 are respectively oriented perpendicularly thereto. This enables the frequency components in both axes to be determined.
  • the other cells 15, 17, 19, 21, 23, 25 are gray cells with different gray levels, light gray, medium gray and dark gray.
  • the center of the measuring field 5 is covered with a black circle 41 as a locating aid.
  • a quadrant 16 of the measuring field 5 has a defined gray level, which serves as a brightness reference.
  • the last quadrant of the measuring field is each occupied by a white measuring cell 39, a red measuring cell 9, a green measuring cell 14 and a blue measuring cell 13, which are used for color measurement.
  • a distortion profile can also be determined from the evaluation of the projection of the known test image 5 onto the measurement field 6 from FIG. 1 , with the aid of which corresponding images can be rectified.
  • the respective position of the centering points 41 in the test image is known, so that the location of the images of the centering points 41 reflects distortions.
  • Starting from the The position of the outermost centering points is to be determined in the known grid, the target positions of the other centering points. With the actual positions measured in each case, the distortion results in accordance with the deviations in the individual reference locations.
  • the interpolated compilation of the distortion values is the distortion profile.
  • the distortion profile can be used to edit images similarly projected through the same object, as can the sharpness profile or color profile.
  • corrections or partial corrections of the individual courses are not tied to a specific order, but in individual cases, a certain order can show advantageous differences in the result from others.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Geometry (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Optics & Photonics (AREA)
  • Testing, Inspecting, Measuring Of Stereoscopic Televisions And Televisions (AREA)

Abstract

L'invention concerne un dispositif de détermination d'un profil d'intensité et/ou de couleur et/ou de netteté d'un système de lentilles optique (3) projetant une image de test (1) constituée de champs de mesure (5). Selon l'invention, la projection est dirigée indirectement ou directement sur un champ (6) de capteurs de couleurs et de luminosité de résolution élevée. Les signaux de mesure desdits capteurs mis en corrélation avec les champs de mesure (5) sont alimentés à un ordinateur (60) déterminant à partir de ceux-ci le profil d'intensité et/ou de couleur et/ou de netteté et/ou un profil de distorsion. L'ordinateur transmet ensuite lesdits profils à un système de traitement d'images (62) destiné à la correction électronique de défauts d'images (B) produites avec un système de lentilles identique (3), ou enregistre lesdits profils ou les enregistre de manière intermédiaire sur un support de données (61).
EP02738120A 2001-05-30 2002-05-28 Dispositif de determination d'un profil d'intensite et de couleur et/ou de nettete de systemes de lentilles optiques Withdrawn EP1393113A2 (fr)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
DE10126546 2001-05-30
DE10126546A DE10126546A1 (de) 2001-05-30 2001-05-30 Vorrichtung und Verfahren zur Ermittlung eines ortsabhängigen Intensitäts- und Farbprofils und/oder Schärfeprofils optischer Linsensysteme
DE20111617U 2001-07-12
DE20111617U DE20111617U1 (de) 2001-07-12 2001-07-12 Vorrichtung zur Ermittlung eines ortsabhängigen Intensitäts- und Farbprofils und/oder Schärfeprofils optischer Linsensysteme
PCT/EP2002/005859 WO2002097507A2 (fr) 2001-05-30 2002-05-28 Dispositif de determination d'un profil d'intensite et de couleur et/ou de nettete de systemes de lentilles optiques

Publications (1)

Publication Number Publication Date
EP1393113A2 true EP1393113A2 (fr) 2004-03-03

Family

ID=26009447

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02738120A Withdrawn EP1393113A2 (fr) 2001-05-30 2002-05-28 Dispositif de determination d'un profil d'intensite et de couleur et/ou de nettete de systemes de lentilles optiques

Country Status (2)

Country Link
EP (1) EP1393113A2 (fr)
WO (1) WO2002097507A2 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8094195B2 (en) * 2006-12-28 2012-01-10 Flextronics International Usa, Inc. Digital camera calibration method
KR101325988B1 (ko) 2010-10-29 2013-11-07 엘지디스플레이 주식회사 입체 디스플레이의 광학 측정 장치 및 방법
CN115550640B (zh) * 2022-10-09 2024-07-05 知行汽车科技(苏州)股份有限公司 一种逆畸变清晰度测试图卡设计方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4513319A (en) * 1981-12-30 1985-04-23 U.S. Philips Corporation Method for automatically setting up a television camera
US4991007A (en) * 1989-05-05 1991-02-05 Corley Ferrand D E Image evaluation of at least one characteristic of an object, and method of evaluation
JP3635392B2 (ja) * 1998-03-17 2005-04-06 コニカミノルタホールディングス株式会社 画像処理装置

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO02097507A3 *

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Publication number Publication date
WO2002097507A2 (fr) 2002-12-05
WO2002097507A3 (fr) 2003-03-20

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