WO2009088146A1 - Appareil et procédé de lecture d'image - Google Patents

Appareil et procédé de lecture d'image Download PDF

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Publication number
WO2009088146A1
WO2009088146A1 PCT/KR2008/005318 KR2008005318W WO2009088146A1 WO 2009088146 A1 WO2009088146 A1 WO 2009088146A1 KR 2008005318 W KR2008005318 W KR 2008005318W WO 2009088146 A1 WO2009088146 A1 WO 2009088146A1
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WO
WIPO (PCT)
Prior art keywords
light
refractive index
image
wavefront coding
amount
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/KR2008/005318
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English (en)
Inventor
Jong-Chul Choi
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.)
Samsung Electronics Co Ltd
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Samsung Electronics Co Ltd
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Filing date
Publication date
Application filed by Samsung Electronics Co Ltd filed Critical Samsung Electronics Co Ltd
Publication of WO2009088146A1 publication Critical patent/WO2009088146A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/04—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
    • G03G15/0409—Details of projection optics
    • G—PHYSICS
    • G06—COMPUTING OR CALCULATING; COUNTING
    • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
    • G06V10/00—Arrangements for image or video recognition or understanding
    • G06V10/10—Image acquisition
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/04—Apparatus for electrographic processes using a charge pattern for exposing, i.e. imagewise exposure by optically projecting the original image on a photoconductive recording material
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/50—Machine control of apparatus for electrographic processes using a charge pattern, e.g. regulating differents parts of the machine, multimode copiers, microprocessor control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/10—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using flat picture-bearing surfaces
    • H04N1/1013—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using flat picture-bearing surfaces with sub-scanning by translatory movement of at least a part of the main-scanning components
    • H04N1/1017—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using flat picture-bearing surfaces with sub-scanning by translatory movement of at least a part of the main-scanning components the main-scanning components remaining positionally invariant with respect to one another in the sub-scanning direction
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/19—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays
    • H04N1/191—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays the array comprising a one-dimensional [1D] array
    • H04N1/192—Simultaneously or substantially simultaneously scanning picture elements on one main scanning line
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/04—Scanning arrangements
    • H04N2201/0402—Arrangements not specific to a particular one of the scanning methods covered by groups H04N1/04 - H04N1/207
    • H04N2201/0434—Arrangements not specific to a particular one of the scanning methods covered by groups H04N1/04 - H04N1/207 specially adapted for scanning pages of a book

Definitions

  • the present invention generally relates to an image reading apparatus and method, and more particularly, to an image reading apparatus and method capable of improving scanned image quality.
  • An image reading apparatus reads a scan object by radiating light.
  • Examples of an image reading apparatus may include a scanner, a facsimile, a copier, and a multifunctional scanner/facsimile/copier device, a digital camera, or the like.
  • An image reading apparatus includes flat glass, on one side of which an object to be scanned may be placed, and a scanning system located on the other side of the flat glass for reading the scan object.
  • the scanning system may include a light source unit for radiating light to the scan object, an image sensor for converting a light signal obtained from light reflected from the scan object into an electric signal, a light path forming unit for delivering the light reflecting from the scan object to the image sensor and an imaging lens for condensing the light delivered to the image sensor.
  • the light path forming unit may include, e.g., a plurality of mirrors.
  • a scanning system generally in use may have a maximum depth of focus of about ⁇ 2 mm.
  • image blurring may occur, resulting in deterioration of image.
  • the scan object is a unfolded bound book
  • the distance between the flat glass and the book at the binding portion of the book where two leaves meet may become large, and may exceed the maximum depth of focus, the scanned image of the fold portion being blurred and distorted
  • FIG. 1 illustrates a state where the bound book is put face down on the flat glass, in which d 0 indicates a distance between a reference plane and an edge page portion contacting the flat glass 5, and U 1 and d 2 indicate distances between the reference plane and page portions near the binding portion where 2 leaves meet. It is assumed that a scan object exists in the page portions. When U 1 - d 0 or d 2 - d 0 is greater than the depth of focus of the scanning system, a scan image obtained from the corresponding page portion may become blurred and/or distorted, resulting in deterioration of the scan image.
  • Signal light obtained by reading a scan object may be made insensitive to defocus by using wavefront coding and may be input to an image sensor. A signal obtained by the image sensor may then be decoded by signal processing, thereby reducing image blurring.
  • FIG. 1 illustrates a state where an unfolded book is put face down on flat glass
  • FIG. 2 schematically illustrates a structure of an image reading apparatus according to an embodiment of the invention
  • FIG. 3 schematically illustrates the structure of a focus state detecting unit according to an embodiment of the invention
  • FIGS. 4 A through 4C illustrate various examples of arrangements of a plurality of light-amount detecting sensors across a scanning direction, according to various embodiments of the invention
  • FIGS. 5 A and 5B schematically illustrate an active wavefront coding element according to an embodiment of the invention
  • FIGS. 6 A and 6B schematically illustrate an active wavefront coding element according to another embodiment of the invention.
  • FIG. 7 schematically illustrates a light source unit according to an embodiment of the invention
  • FIGS. 8 A and 8B schematically illustrate additional examples of a wavefront coding element according to an embodiment of the invention.
  • FIG. 9 is a flowchart illustrating an image reading method using an image reading apparatus according to an embodiment of the invention.
  • FIG. 10 illustrates graphs for comparing modulation transfer function (MTF) before and after wavefront coding.
  • an image reading apparatus may include a light source unit 20, which radiates light to a scan object 1 placed on a transparent plate 5, an image sensor 50, which converts the signal light obtained by reading a scan region A of the scan object 1 from the light radiated by the light source unit 20 into an electric signal, a focus state detecting unit (including a light-amount detecting sensor 10), which detects the focus state of the scan object 1, and a wavefront coding unit 40 which applies wavefront coding to the signal light in order to make the signal light insensitive to defocus, i.e., to lessen the effect of defocus condition on the signal light.
  • a light source unit 20 which radiates light to a scan object 1 placed on a transparent plate 5
  • an image sensor 50 which converts the signal light obtained by reading a scan region A of the scan object 1 from the light radiated by the light source unit 20 into an electric signal
  • a focus state detecting unit including a light-amount detecting sensor 10
  • a wavefront coding unit 40 which applies wave
  • the image reading apparatus may further include a light path forming unit which forms a light path for delivering the light reflected from the scan region A of the scan object 1 to the image sensor 50, and may include a plurality of mirrors 31, 33, and 35.
  • the image reading apparatus may further include an imaging lens 37, which condenses the light signal delivered to the image sensor 50.
  • the image reading apparatus typically reads an image in the unit of a line by simultaneously radiating light to the scan region A.
  • the scan region A means a line-based region of the scan object 1 on which image reading is performed.
  • the line-based region to which light is simultaneously radiated corresponds to the main scanning direction of an image forming apparatus such as a printer while the scanning direction of the image reading apparatus corresponds to the sub-scanning direction of the image forming apparatus.
  • the image reading apparatus may perform image reading while moving the entire scanning optical system or a portion thereof in the scanning direction of the image reading apparatus.
  • the image sensor 50 may be a charge-coupled device (CCD) sensor, a CMOS sensor, a contact image sensor (CIS), or another equivalent device capable of converting a light signal into an electric signal.
  • CCD charge-coupled device
  • CMOS complementary metal-oxide-semiconductor
  • CIS contact image sensor
  • the transparent plate 5 may accept the scan object 1, which for example may be a document, manuscript or a book to be scanned, and may contact the scan object 1.
  • the transparent plate 5 may be made of flat glass or another substantially flat transparent material.
  • the light source unit 20 may include a lamp light source 21 which generates light in a line shape.
  • the lamp light source 21 may be a halogen lamp or similar device.
  • the light source unit 20 may further include a reflective mirror 23 in order to direct light radiated from the lamp light source 21 towards the scan object 1.
  • the reflective mirror 23 may be a curved- surface mirror whose cross section forms a portion of an oval or a circle, and whose length corresponds to the length of the lamp light source 21.
  • An image reading apparatus typically reads an image in linear units, e.g., a line at a time, by simultaneously radiating light to the scan region A.
  • scan region A may denote a line -based region of the scan object 1 on which an image reading operation is to be performed.
  • the line -based region to which light is simultaneously radiated may correspond to a main scanning direction of an image forming apparatus such as a printer, and a scanning direction of the image reading apparatus may correspond to a sub-scanning direction of the image forming apparatus.
  • the image reading apparatus may perform image reading while moving the entire scanning optical system or a portion thereof in the scanning direction of the image reading apparatus.
  • the focus state detecting unit may detect a focus state of the scan object 1. In one embodiment of the invention, the focus state detecting unit may do so by checking whether light is radiated with focus or defocus to a particular region of the scan object 1 from which an image is read.
  • Light may be radiated from the light source unit 20 to a particular region of the scan object 1 instead of being radiated in a line shape. As a result, some light may be radiated to a neighboring region B that is located adjacent to, and in front of, the scan region A. By monitoring the amount of light reflected from the neighboring region B, the focus state of the scan object 1 may be obtained.
  • the focus state detecting unit may include a light amount detecting sensor 10, which detects the amount of light reflected from the neighboring region B of the scan object 1.
  • the focus state detecting unit may further include a focus state judging unit 60, which may judge whether light is radiated with correct focus on the scan object 1 based on a detection signal obtained by the light-amount detecting sensor 10.
  • a light-amount detecting sensor 10 may include, for example, a photodiode capable of producing varying levels of output signals based on the amount of light received.
  • the focus state judging unit 60 may include, for example, an analog comparator having an input coupled to the output of the light-amount detecting sensor 10, another input for receiving a reference value, and an output for outputting a signal indicative of whether the output from the light- amount detecting sensor 10 is larger of smaller than the reference value.
  • the active wavefront coding unit will be described in more detail later.
  • the scan object 1 is placed on the transparent plate 5, and the change in the focus occurs in the direction moving further away from the transparent plate 5.
  • the light- amount change may also occur according to the surface state of the scan object 1. For example, a difference may exist in the amount of light be generated between scanning of a dark portion of the scan object 1 and scanning of a bright portion of the scan object 1.
  • a plurality of light-amount detecting sensors 10 may be spaced apart from each other across the scanning direction as illustrated in FIGS. 4A through 4C. This spacing may enable the focus state detecting unit to distinguish a light-amount difference originating from a scan surface state and a light- amount difference originating from defocus.
  • FIG. 4A illustrates an embodiment where two light-amount detecting sensors 10 (Sl and S2) are arranged.
  • FIG. 4B illustrates an embodiment where three light-amount detecting sensors 10 (Sl, S2, and S3) are arranged.
  • FIG. 4C illustrates an embodiment where n light-amount detecting sensors 10 (Sl, S2, ..., Sn) are arranged.
  • a scan region of the scan object 1 is in a defocused state.
  • the wavefront coding unit 40 may operate to apply wavefront coding. If only some of the detection light amounts are less than the threshold level, a light-amount difference may have originated from the scan surface state, and wavefront coding is not used.
  • the scan object 1 is in a focused state. In this state the scan object 1 may properly be scanned to form the scanned image.
  • the wavefront coding unit 40 may include a controller (not shown), which may be, e.g., a microprocessor, a microcontroller or the like, that includes a CPU to execute one or more computer instructions to implement the operations of controlling the wavefront coding unit 40 as described herein, and may further include a memory device, e.g., a Random Access Memory (RAM), Read- Only-Memory (ROM), a flesh memory, or the like, to store the one or more computer instructions.
  • the controller may serve as the main controller for the image reading apparatus, and perform other aspects of controlling the image reading apparatus.
  • the threshold level may be a reference level that is set by the light- amount detecting sensors 10 by defocusing the scan object 1 during scan unit initial setting.
  • the reference level may be a detection value obtained by the light-amount sensor 10 when the scan region of the scan object 1 is spaced d 0 from the reference plane illustrated in FIG. 1 or is located within the depth of focus of light radiated from the light source unit 20 for d 0 .
  • the light-amount detecting sensor 10 may detect a smaller light-amount than the reference level.
  • the light-amount sensor 10 may be able to determine whether or not the scan region of the scan object 1 is in a defocused state by comparing the detection value with the threshold level.
  • the light-amount detecting sensor 10 may be disposed in a position where the specular reflection components may reach. In this case, reflection from the surface of the transparent plate 5 may become an issue.
  • the amount of light reflected from the surface of the transparent plate 5 may be reduced to be less than the amount of specular reflection components from the scan object 1, according to the Fresnel reflection equation. Therefore, by using light reflected from the scan object 1, the focus state of the scan object 1 can be determined.
  • the wavefront coding unit 40 may modulate the wavefront of the light signal reflected from the scan region A in order to deliver a light signal to the image sensor 50 that is insensitive to the defocus.
  • the wavefront coding unit 40 may be disposed in front of the imaging lens 37 as shown in FIG. 2.
  • the wavefront coding unit 40 may be an active wavefront coding element 40' or 40" as illustrated in FIGS. 5 A through 6B.
  • FIGS. 5 A and 5B illustrate the active wavefront coding element 40' according to an embodiment of the invention while FIGS. 6 A and 6B illustrate the active wavefront coding element 40" according to another embodiment of the invention.
  • the active wavefront coding element 40' may include a first transparent substrate 41, a second transparent substrate 44, an active double refraction layer 43 (or 43'), which is disposed between the first transparent substrate 41 and the second transparent substrate 44, and which may have an effective refractive index that changes according to whether or not an electric field is applied, and a refractive index correcting plate 42 (or 42') whose interface with the active double refraction layer 43 (or 43') has a shape corresponding to phase distribution for wavefront coding.
  • the refractive index of the active double refraction layer 43 (or 43') such that the refractive index is the same as or different from that of the refractive index correcting plate 42 (or 42'), the wavefront of incident light can be actively modulated.
  • FIGS. 5 A through 6B illustrate embodiments where the active double refraction layer 43 (or 43') is a liquid crystal layer.
  • the active double refraction layer 43 (or 43') undergoes a refractive index change and thus serves as a wavefront coding phase element.
  • the refractive index change is due to a change of liquid crystal arrangement caused by the electric field applied to the active double refraction layer 43 (or 43').
  • the switch 47 when the switch 47 is open, the liquid crystal arrangement returns to its original state and thus the active double refraction layer 43 (or 43') does not serve as a wavefront coding phase element.
  • the active wavefront coding element 40' may also be structured such that a voltage may be applied to both of the first transparent substrate 41 and the second transparent substrate 44, and the refractive index correcting plate 42 (or 42') may be made of a material which, when in a state where the electric field is not applied to the liquid crystal (as illustrated in FIGS. 5B and 6B), has the same refractive index as that of the active double refraction layer 43 (or 43').
  • a wavefront coding element capable of optically changing a phase may use one of the following 2 methods to cause the phase change. [Table 1] [Table ]
  • the refractive correcting plate 42 is structured to cause a phase change in an asymmetric shape while, in the wavefront coding element 40" illustrated in FIGS. 6A and 6B, the refractive correcting plate 42' is structured to cause a phase change in a symmetric shape.
  • the material used for the active double refraction layer 43 (or 43') may be liquid crystal that reacts to polarized light or liquid crystal that reacts to non-polarized light.
  • a polarization aligner 25 (see FIG. 7) may be further included in the emitting side of the light source unit 20.
  • the polarization aligner 25 may be disposed at the exit side through which light is emitted from the lamp light source 21 and the reflective mirror 23, e.g., shown in FIG. 2.
  • the polarization aligner 25 may include a polarization beam splitter array 26 which transmits or reflects incident light according to polarization, reflective mirrors 28, each of which is disposed in front of one of a set of polarization beam splitters in order to reflect the incident light, and 1/2 wave plates 27, each of which is disposed at the rear of a polarization beam splitter adjacent to one of the set of polarization beam splitters to change a linearly polarized light into another linearly polarized light.
  • a wavefront coding unit 40 may include a fixed wavefront coding phase element 140 (or 140') and a driving unit 145.
  • the fixed wavefront coding phase element 140 (or 140') includes a pair of medium layers of different refractive indices which have a mutual interface in a shape corresponding to phase distribution for wavefront coding.
  • the driving unit 145 may insert the fixed wavefront coding phase element 140 (or 140') into a light path or remove the fixed wavefront coding phase element 140 (or 140') from the light path.
  • FIG. 8 A illustrates an embodiment in which the wavefront coding phase element 140 is structured to cause a phase change in an asymmetric shape while FIG. 8B illustrates an embodiment in which the wavefront coding phase element 140' is structured to cause a phase change in a symmetric shape.
  • the fixed wavefront coding phase element 140 may include a first optical member 142 corresponding to the refractive index correcting plate 42 and a second optical member 143 corresponding to the active double refraction layer 43 in order to cause a phase change in an asymmetric shape.
  • the first optical member 142 may have the same structure as that of the refractive index correcting plate 42 and the second optical member 143 may be a transparent substance or a liquid crystal layer having a different refractive index than that of the first optical member 142.
  • a transparent substrate (not shown) may further be included on the second optical member 143.
  • the fixed wavefront coding phase element 140' may on the other hand include a first optical member 142' corresponding to the refractive correcting plate 42' and a second optical member 143' corresponding to the active double refraction layer 43' in order to cause a phase change in a symmetric shape.
  • the first optical member 142' may have the same structure as that of the refractive index correcting plate 42' and the second optical member 143' may be a transparent substance or a liquid crystal layer having a different refractive index than that of the first optical member 142'.
  • a transparent substrate (not shown) may further be included on the second optical member 143'.
  • FIG. 9 is a flowchart illustrating an image reading method, which may be practiced by an image reading apparatus according to an embodiment of the invention.
  • the described operations may be performed by a controller (not shown) of the image reading apparatus, which may be the same controller previously described above, or may be a separate controller that may be, e.g., a microprocessor, a microcontroller or the like, that includes a CPU to execute one or more computer instructions to implement the operations as described herein, and may further include a memory device, e.g., a Random Access Memory (RAM), Read- Only-Memory (ROM), a flesh memory, or the like, to store the one or more computer instructions.
  • RAM Random Access Memory
  • ROM Read- Only-Memory
  • flesh memory or the like
  • the scan object 1 may be placed on the transparent plate 5 in operation SlO, and scanning may begin by radiating light to the scan object 1 placed on the transparent plate 5 in operation S20.
  • the wavefront coding unit 40 is driven to apply wavefront coding to the signal light obtained by image reading in operations S50 and S60, and the scanning continues in this state in operation S70.
  • the signal light read from the scan object 1 is made insensitive to defocus, and is then input to the image sensor 50.
  • the electric signal produced by the image sensor 50 is decoded in operation S 80. The decoding will be described in more detail later.
  • a scanned image is formed from the image data obtained during the decoding in operation S90, which may then be output in operation SlOO.
  • the wavefront coding unit 40 is not operated so as not to perform wavefront coding in operation Sl 10, and the scanning continues in this state in operation S 120.
  • a signal light obtained by reading an image of the scan object 1 during scanning is input to the image sensor 50.
  • a scanned image is formed by using an electric signal obtained by the image sensor 50 in operation S90, which is output in operation SlOO.
  • a plurality of light-amount detecting sensors are provided.
  • the light- amount detecting sensors 10 are spaced apart from each other across the scanning direction of the image reading apparatus. In these embodiments, wavefront coding is applied only when all detection light amounts obtained by the plurality of light-amount detecting sensors 10 are less than the threshold level.
  • the discrepancy may be due to the surface reflection difference in the scan object 1 rather than the state of focus. In this case a scan image is directly output without wavefront coding.
  • Wavefront coding is modulation of an optical wavefront emitted from an optical system. Wavefront coding may allow the optical system to form an emitting wavefront regardless of focus, and the resulting image obtained may be clearly produced with signal processing even when defocus occurs. Imaging and reconstruction may be described with reference to the diagram below.
  • Im .. indicates an output image produced by the sensor, which had received the image through the optical system.
  • the input image may be calculated as follows:
  • G(s)' indicates a product of an imaging optical system and a function of a phase plate for modulating an emitting wavefront.
  • G(sy G(s) ® P(s)
  • encoding indicates an optical result and decoding indicates image reconstruction by signal processing.
  • ⁇ -'(s) 1 indicates a result of performing an inverse FFT on a function of the product of the lens and the phase plate, which may be a point spread function (PSF) of the optical system, and can be obtained by CODE V.
  • a PSF may need to be obtained for every wavelength, every defocus, and every field.
  • FIG. 10 illustrates graphs for comparing MTF changes caused by defocus before and after the performance of wavefront coding.
  • wavefront coding may be implemented as an asymmetric phase change or as an axially- symmetric phase change.
  • the asymmetric phase change may optimize a wavefront coding phase element such that focus changes in a top- to-bottom direction and the axially-symmetric phase change may optimize a wavefront coding phase element such that focus changes in a radial direction.
  • wavefront coding may be applied when the scan object 1 in not in proper focus. This may be done in order to make a signal light obtained by reading the scan object 1 insensitive to defocus and to detect the signal light by using the image sensor 50. By decoding a detection signal obtained by the image sensor 50, a clear scan image can be obtained.
  • signal light obtained by reading a scan object may be made insensitive to defocus by using wavefront coding and may be input to an image sensor.
  • a signal obtained by the image sensor may then be decoded by signal processing, thereby reducing image blurring.

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  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Multimedia (AREA)
  • Theoretical Computer Science (AREA)
  • Signal Processing (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Optics & Photonics (AREA)
  • Facsimile Scanning Arrangements (AREA)

Abstract

L'invention porte sur un appareil et sur un procédé de lecture d'image qui peuvent lire des images au-delà de la profondeur de foyer maximale, sans détérioration d'image substantielle. L'appareil de lecture d'image comprend une unité de source de lumière rayonnant une lumière vers une région de balayage d'un objet de balayage placé sur une plaque transparente, un détecteur d'image convertissant un signal lumineux obtenu par lecture de la région de balayage de l'objet de balayage en un signal électrique, une unité de détection d'état de mise au point détectant un état de mise au point de l'objet de balayage, et une unité de codage de front d'onde. L'unité de codage de front d'onde module un front d'onde de la lumière réfléchie à partir de la région de balayage de l'objet de balayage afin d'entrer une lumière qui est rendue insensible à une défocalisation dans le détecteur d'image. Ceci est fait lorsqu'il est déterminé par l'unité de détection d'état de mise au point que la lumière est rayonnée vers l'objet de balayage dans un état de mise au point incorrect sur l'objet de balayage.
PCT/KR2008/005318 2008-01-11 2008-09-09 Appareil et procédé de lecture d'image Ceased WO2009088146A1 (fr)

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Cited By (1)

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Publication number Priority date Publication date Assignee Title
CN104601847A (zh) * 2013-10-31 2015-05-06 京瓷办公信息系统株式会社 图像读取装置

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US6360012B1 (en) * 1999-06-25 2002-03-19 Svg Lithography Systems, Inc. In situ projection optic metrology method and apparatus
US20040227944A1 (en) * 2003-02-28 2004-11-18 Nikon Corporation Mark position detection apparatus
WO2005069280A2 (fr) * 2004-01-08 2005-07-28 Thomson Licensing Procede de determination de l'aberration spherique

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Publication number Priority date Publication date Assignee Title
US5548403A (en) * 1994-11-28 1996-08-20 The Regents Of The University Of California Phase shifting diffraction interferometer
US6360012B1 (en) * 1999-06-25 2002-03-19 Svg Lithography Systems, Inc. In situ projection optic metrology method and apparatus
US20040227944A1 (en) * 2003-02-28 2004-11-18 Nikon Corporation Mark position detection apparatus
WO2005069280A2 (fr) * 2004-01-08 2005-07-28 Thomson Licensing Procede de determination de l'aberration spherique

Cited By (2)

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CN104601847A (zh) * 2013-10-31 2015-05-06 京瓷办公信息系统株式会社 图像读取装置
CN104601847B (zh) * 2013-10-31 2017-12-19 京瓷办公信息系统株式会社 图像读取装置

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