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WO1992015084A1 - Procede et appareil d'etalonnage geometrique d'un systeme d'entree optique d'ordinateur - Google Patents

Procede et appareil d'etalonnage geometrique d'un systeme d'entree optique d'ordinateur Download PDF

Info

Publication number
WO1992015084A1
WO1992015084A1 PCT/US1992/000876 US9200876W WO9215084A1 WO 1992015084 A1 WO1992015084 A1 WO 1992015084A1 US 9200876 W US9200876 W US 9200876W WO 9215084 A1 WO9215084 A1 WO 9215084A1
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WO
WIPO (PCT)
Prior art keywords
coordinate
image
value
determined
algorithm
Prior art date
Application number
PCT/US1992/000876
Other languages
English (en)
Inventor
Roger N. Marshall
Original Assignee
Proxima Corporation
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 Proxima Corporation filed Critical Proxima Corporation
Publication of WO1992015084A1 publication Critical patent/WO1992015084A1/fr

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Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/042—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by opto-electronic means
    • G06F3/0425—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by opto-electronic means using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected

Definitions

  • the present invention relates in general to a method in apparatus for calculating geometrically an optical computer input system. It more particularly relates to a system for calibrating geometrically for distortion in connection with such an optical computer input system is shown and described in the said patent application.
  • a new optical computer input system is shown and described in said parent patent application.
  • Such system enable the use to shine a high intensity light onto a screen bearing a computer generated image to provide auxiliary information for the computer.
  • Such an input system includes an optical sensing device, such as a charged coupled device camera focused on to the screen.
  • the system can detect high intensity light images and discriminate them from the computer generated images, to input information interactively into the computer, in a convenient manner, even in very low ambient light conditions.
  • the screen onto which is projected the computer generated image may not be a perfect rectangle as presented to the sensing device or camera.
  • the screen may be tilted either forward or backward, or from side to side, or any combination thereof.
  • the sensing device or camera will not track properly relative to the image visualized from the screen.
  • keystoning problem produces an image which has a longer top edge as compared to its bottom edge.
  • Such keystoning problem is well known with overhead projectors, and thus, the sensing device or camera will produce a distortion in sensing the image projected into the computer.
  • a third problem is caused by the improper alignment of a projection panel on the stage of the overhead projector. In this regard, if the panel is not
  • the resulting image projected onto the screen will also be askew.
  • a fourth problem relates to the project itself not being properly aligned relative to the screen. Such is commonly the case where the neck portion of the overhead projector may be bent slightly due to excessive use or wear. This causes a result similar to the improper registration of the panel on the stage of the projector.
  • a still further problem of geometric alignment is caused by the camera or sensing device being tilted at an angle being tilted upwardly, or downwardly, relative to the plane of the screen. The result is that a distortion may occur.
  • the camera is unable to accurately plot the various coordinates visualized from the image projected on to the screen.
  • tracking is not able to be perfectly accomplished.
  • the camera may not accurately know the precise coordinates of the spot of light
  • the computer may not accurately respond to the position of the light and incorrect data can be entered. Thus, erroneous results might occur.
  • the principle object of the present invention is to provide a new and improved geometric correction arrangement for an optical imaging system.
  • the system of the present invention produces a normalization of the image of the screen to provide for the necessary correction.
  • FIG. 1 is a block diagram of the imaging system
  • FIGS. 2 through 11 are diagrammatic views of various images or portions of images helpful in understanding the operation of the present invention.
  • FIGS. 12 through 17 are flow charts of computer software for the system of FIG. 1 to illustrate the operation of the geometric correction arrangement.
  • FIG. 1 there is illustrated a computer input system 10 which modifies computer generated images appearing on a screen 21, and which is constructed in accordance with the present invention.
  • the computer input system 10 generally includes an image
  • the projection/detection system or arrangement 11 whose input path (cable 17A) is coupled to the output of a video port 17 of a computer 16.
  • the arrangement 11 comprises a liquid crystal panel 13 and a charge coupled device image sensor 14.
  • the computer 16 is a conventional personal computer, such as a model PS/2 personal computer
  • the computer 16 includes a video monitor 19A and keyboard 19B.
  • the panel 13 is driven by the computer 16, for generating live images which are projected by an overhead head projector 22 onto the screen 21.
  • the computer input system 10 also includes a signal processing unit 25 coupled between the output path (cable 14A) of the image/detection arrangement 11 and the input serial port 18 of the computer 16 via cable 25A.
  • the computer input system 10 further includes a light wand or light generating pointing device 24, or a laser light generating device.
  • the projection/detection arrangement 11 detects the presence of auxiliary light image or spot projected onto the viewing surface 21 by the handheld/battery-operated light generating device 24, and generates an analog electrical signal which is coupled to the signal
  • the signal processing unit 25 responds to the analog signal, and converts the signal into digital pixel coordinates reference signals which identify the relative position of the auxiliary light image on screen 21, which are transferred into the computer 16 via the output cable 25A.
  • Cable 25A is connected to the serial input port 18 of the computer 16.
  • Computer 16 responds to the pixel coordinates signals and can alter its application program which causes the computer generated image being projected onto the screen 21 to be modified. For example, the computer generated projected image on the viewing area 21 can be modified in accordance with the information contained in the
  • the firmware stored in the signal processor 25 provides the necessary geometric correction for the image in accordance with the present invention. As shown in FIG. 2, the correction commences by projecting a bright rectangular light onto the screen to determine what correction is necessary and then record the necessary information for converting the coordinates to an adjusted relative coordinate. As shown on FIG. 2, a true
  • each one of the four sides of the image can be distorted in a generally rectangular manner.
  • the arrangement of the present invention determines which one of the two triangular areas of distortion are present for each side of the rectangular image. Once that determination is made, a formula for the relative correction is generated and stored in the signal processor. Thus, there are eight possible triangular areas of distortion indicated at 81 through 88.
  • FIG. 3 there is shown an example of a grossly distorted rectangular image 90 as an example.
  • the first portion of the process or technique for doing the correction is the actual corners of the projected image are shown.
  • the coordinates for the individual corners are shown in FIG. 3.
  • the technique for determining the corners are similar as shown and described in the parent applications.
  • a defined central coordinate of X , Y is located at the
  • the image sensor 14 determines the interface between the bright image and the remaining portion of the screen, in a similar manner as described in the parent patent applications.
  • the geometric center of the screen is determined and defined at the intersection of diagonal *** lines extending through the corners. And thereafter, as indicated in box 122 in FIG. 12, and as shown in FIG. 3, the geometric center of the screen is determined and defined at the intersection of diagonal *** lines extending through the corners. And thereafter, as indicated in box 122 in FIG. 12, and as shown in FIG. 3, the geometric center of the screen is determined and defined at the intersection of diagonal *** lines extending through the corners. And thereafter, as
  • a position X of the spot of light is determined to be either left of center or not. If it is determined to be left of center, then the software will analyze whether the left edge is in perfect vertical alignment or whether it is distorted according to either one or the other triangular areas of distortion 81 or 82, as indicated more clearly in FIGS. 4 and 5. As indicated in box 124, a determination is made as to whether or not the left edge is a perfectly aligned vertical edge. In this regard, the X coordinate of the top, left corner is compared with the X coordinate bottom, left corner. If they are equal, then the edge is determined to be perfectly oriented in a vertical
  • box 131 of FIG. 13 is entered.
  • the decision box 125 is entered as shown in FIG. 12 to determine whether the X coordinate of the top left corner is greater than the bottom left corner. This determination is made to learn whether there is rectangular distortion area 81 (FIG. 4), or a triangular area of distortion shown at 82 of FIG. 5.
  • the triangular area 81 is in the shape of a right of a triangle having its based aligned with the bottom edge of the rectangular image.
  • the rectangular area 82 is inverted from the area 81, and has its base coextensive with the top edge of the rectangular image area.
  • triangular image area 82 is present. In such a
  • the box 126 is entered and the left edge X coordinate is calculated in the box 126. Thereafter, at the box 132, 133 the absolute value of the X coordinate of the spot is calculated. This value of the X
  • the formula shown in the boxes 132 and 133 are used to scale the X coordinate of the spot of light on the screen 21 to correct geometrically for any
  • the initial storing of the X and Y coordinates of the four corners and the defined center is the only information that need be saved during initialization process. Thereafter, the absolute values of the X and Y coordinates of the spot of light are calculated and supplied to the host computer 16 on the fly.
  • the decision box 125 of FIG. 12 will determine that the top left X coordinate is not greater than the bottom left X coordinate, so that the box 126 is entered to calculate the left edge X coordinate. After so calculating, the boxes 132 and 133 are entered to determine a different X ABSOLUTE value based upon the triangular area 81 of distortion. Referring again to box 123 to where the X coordinate position of the light spot is determined to be left of center, if it is not left of center then the decision box 141 of FIG. 14 is entered.
  • box 141 there is determination made as to whether the top right X coordinate is equal to the bottom right X coordinate. If they are equal then box 145 is entered directly to determine if the right edge X coordinate is equal to the X coordinate of the top right edge.
  • the box 142 is entered to determine whether or not the top right X coordinate is greater than the bottom right X coordinate. If it is, then the right edge X coordinate is calculated by the formula shown in box 143. Thereafter, as
  • the absolute value of the X coordinate is then calculated knowing the right edge X coordinate and the X coordinate of the light spot and the X coordinate of the defined center. This absolute value of X is then used and supplied to the host computer 16.
  • the triangular area 83 (FIG. 2) is identified and the box 144 is entered to calculate the X coordinate of the right edge, thereafter, calculations are made at boxes 151 and 152 calculating the absolute value of the X coordinate.
  • the quadrant of the light spot is first determined at box 153. In this regard, at box 153 a determination is made as to whether or not the Y position of the spot is above the defined center. If it is, then the decision box 154 is entered to determine whether the top edge is either horizontal or whether there are either one or two triangular areas 85 or 86 as shown in FIG. 2.
  • triangular area 86 is present. If the decision is positive, then the triangular area 86 is identified and the calculation shown in box 156 is made to determine the top edge Y coordinate. Thereafter, as shown in box 163 (FIG. 16A), and box 164 of FIG. 16A, the absolute value of Y is then determined for supplying it to the host computer 16. This value of the absolute value of Y is a scaled value of the Y coordinate of the spot.
  • a box 176 in FIG. 17 is entered to prepare and transmit to the host computer once both absolute value of the X coordinate and the absolute value of the Y coordinates have been calculated. It should be noted that once these absolute values have been transmitted, the routine loops back to the initial box 123 to repeat the cycle of operation for the next light spot detected.
  • Y coordinate The purpose of this determination is to decide whether the bottom edge of the rectangular viewing area is either horizontal, or at a triangular position as indicated at either 87 or 88 in FIG. 2. If it is
  • box 165 determines whether or not the bottom left Y coordinate is greater than the bottom right Y coordinate. If it is, then the box 171 is entered to perform a calculation to determine the bottom edge value of the Y coordinate.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Multimedia (AREA)
  • Human Computer Interaction (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Position Input By Displaying (AREA)
  • Transforming Electric Information Into Light Information (AREA)

Abstract

Procédé et appareil permettant d'effectuer des corrections géométriques dans un système d'entrée optique (10) d'un ordinateur. On effectue la correction en projetant tout d'abord une lumière rectangulaire brillante (80) sur l'écran afin de déterminer quelles sont les corrections à effectuer, puis en enregistrant les données nécessaires afin de convertir les coordonnées en coordonnées relatives corrigées.
PCT/US1992/000876 1991-02-14 1992-01-31 Procede et appareil d'etalonnage geometrique d'un systeme d'entree optique d'ordinateur WO1992015084A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US65680391A 1991-02-14 1991-02-14
US656,803 1991-02-14

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WO1992015084A1 true WO1992015084A1 (fr) 1992-09-03

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JP (1) JPH05153532A (fr)
AU (1) AU1445692A (fr)
WO (1) WO1992015084A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000036832A1 (fr) * 1998-12-17 2000-06-22 Gateway, Inc. Systeme, procede et logiciel de correction de la deformation trapezoidale d'une image projetee
WO2004086135A1 (fr) * 2003-03-26 2004-10-07 Matsushita Electric Industrial Co., Ltd. Afficheur video
CN100459676C (zh) * 2003-01-17 2009-02-04 精工爱普生株式会社 图像处理系统，投影机和图像处理方法
DE10003855B4 (de) * 1999-01-29 2010-12-16 Ricoh Co., Ltd. Koordinateneingabevorrichtung, Koordinateneingabeverfahren und Anzeigetafelsystem
WO2016007167A1 (fr) * 2014-07-11 2016-01-14 Hewlett-Packard Development Company, L.P. Génération de coin dans une zone d'affichage de projecteur

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH08179888A (ja) * 1994-12-21 1996-07-12 Hitachi Ltd 大画面ディスプレイ用入力装置
JPH10333088A (ja) * 1997-05-28 1998-12-18 Canon Inc 投射画像の表示方法および投射型画像表示装置
DE19737374C2 (de) 1997-08-27 1999-09-02 Ldt Gmbh & Co Verfahren zur Kompensation geometrischer Bildfehler bei Videobildern sowie ein Projektor zur Durchführung des Verfahrens
JP4613456B2 (ja) * 2000-07-25 2011-01-19 カシオ計算機株式会社 画像表示装置、画像表示方法、および、プログラム
JP4595410B2 (ja) * 2004-07-08 2010-12-08 カシオ計算機株式会社 投影システム、投影条件設定方法及びプログラム

Citations (3)

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Publication number Priority date Publication date Assignee Title
US3966331A (en) * 1973-08-27 1976-06-29 Fuji Photo Film Co., Ltd. Coordinate detecting apparatus for optical projectors
US4845346A (en) * 1987-07-16 1989-07-04 Alps Electric Co., Ltd. Touch panel having parallax compensation and intermediate coordinate determination
US5070465A (en) * 1987-02-25 1991-12-03 Sony Corporation Video image transforming method and apparatus

Family Cites Families (1)

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Publication number Priority date Publication date Assignee Title
FR2652695B1 (fr) * 1989-10-03 1993-04-16 Thomson Csf Procede et dispositif de visualisation d'images, a correction automatique de defauts par contre-reaction.

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3966331A (en) * 1973-08-27 1976-06-29 Fuji Photo Film Co., Ltd. Coordinate detecting apparatus for optical projectors
US5070465A (en) * 1987-02-25 1991-12-03 Sony Corporation Video image transforming method and apparatus
US4845346A (en) * 1987-07-16 1989-07-04 Alps Electric Co., Ltd. Touch panel having parallax compensation and intermediate coordinate determination

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000036832A1 (fr) * 1998-12-17 2000-06-22 Gateway, Inc. Systeme, procede et logiciel de correction de la deformation trapezoidale d'une image projetee
DE10003855B4 (de) * 1999-01-29 2010-12-16 Ricoh Co., Ltd. Koordinateneingabevorrichtung, Koordinateneingabeverfahren und Anzeigetafelsystem
CN100459676C (zh) * 2003-01-17 2009-02-04 精工爱普生株式会社 图像处理系统，投影机和图像处理方法
WO2004086135A1 (fr) * 2003-03-26 2004-10-07 Matsushita Electric Industrial Co., Ltd. Afficheur video
WO2016007167A1 (fr) * 2014-07-11 2016-01-14 Hewlett-Packard Development Company, L.P. Génération de coin dans une zone d'affichage de projecteur
US10318067B2 (en) 2014-07-11 2019-06-11 Hewlett-Packard Development Company, L.P. Corner generation in a projector display area

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Publication number Publication date
AU1445692A (en) 1992-09-15
JPH05153532A (ja) 1993-06-18

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