Classifications

• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; 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
  • G06F3/002—Specific input/output arrangements not covered by G06F3/01 - G06F3/16
  • G06F3/005—Input arrangements through a video camera
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; 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
  • G06F3/011—Arrangements for interaction with the human body, e.g. for user immersion in virtual reality
  • G06F3/013—Eye tracking input arrangements
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
  • H04N13/10—Processing, recording or transmission of stereoscopic or multi-view image signals
  • H04N13/106—Processing image signals
  • H04N13/122—Improving the three-dimensional [3D] impression of stereoscopic images by modifying image signal contents, e.g. by filtering or adding monoscopic depth cues
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
  • H04N13/30—Image reproducers
  • H04N13/332—Displays for viewing with the aid of special glasses or head-mounted displays [HMD]
  • H04N13/337—Displays for viewing with the aid of special glasses or head-mounted displays [HMD] using polarisation multiplexing
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
  • H04N13/30—Image reproducers
  • H04N13/366—Image reproducers using viewer tracking
  • H04N13/376—Image reproducers using viewer tracking for tracking left-right translational head movements, i.e. lateral movements
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N13/00—Stereoscopic video systems; Multi-view video systems; Details thereof
  • H04N13/30—Image reproducers
  • H04N13/366—Image reproducers using viewer tracking
  • H04N13/38—Image reproducers using viewer tracking for tracking vertical translational head movements

Definitions

• the present invention relates to a display system for producing stereoscopic images, and a method corresponding thereto.
• the objective of 3D visual presentation is to enable users to sense spatial shapes as a reality.
• the stereoscopic effect is achieved by conveying separate images to the left and right eyes, in the same way as the eyes sense spatial shapes from their respective different positions.
• a variety of different solutions have been developed for generating and sensing this double image (the so-called "stereo" image).
• 3D display The simplest and most widely used solutions for 3D display are systems based on separating the images simultaneously displayed at the same place by means of polarization. These systems are based on the principle of simultaneously displaying the images intended for the left and right eyes, and separating these two images by a polarization image separation means, a so-called 3D glasses, so that the left side portion thereof lets through only the image intended for the left eye, and the right side portion only the image intended for the right eye. Therefore, the essence of systems based on light polarization is that they produce differently polarized images for the left and right eyes, and separate these images by means of polarization filters placed in front of each eye. Such a solution is disclosed for instance in the WO 2010/015868.
• Some commercially available displays are factory-prepared for polarization- type three-dimensional display. These displays are configured such that the display surface thereof consists of first display regions adapted for displaying the left side image, and second display regions adapted for displaying the right side image. The first and second display regions are disposed in an alternating manner on the display surface. In most cases the individual display regions are implemented as one pixel-high horizontal lines, which implies that the first and second display regions are disposed alternatingly in the vertical direction. These displays are called line-interleaved 3D displays. Separation of polarized images is achieved in this type of display by placing a polarizing layer having oppositely polarized sub regions disposed alternately in front of neighbouring display regions (pixel lines).
• the left and right side images may be displayed in the odd and even lines of the display screen, and the polarizing layer, consisting of differently polarized stripes (preferably having perpendicular linear polarization or opposite circular polarization), allows that the left and right side images may be separated by image separation means worn by the user.
• all line-interleaved 3D displays have the common characteristics that the polarizing layer disposed in front of the display surface cannot be placed on the display surface without a spacing,
• the polarizing layer is disposed in front of the display surface always with a spacing, which causes a quality deterioration of the three-dimensional display in case the individual display regions do not fall right behind the corresponding sub regions of the polarizing layer as seen from the viewpoint of the user.
• the prior art solution to this problem - in connection with the above type of display - consists in including in the user manual a warning that the display should always be viewed from a direction which is facing the display.
• users frequently view three-dimensional displays from positions different from the ideal one, without receiving any feedback from the display system warning them of their incorrect viewing position.
• the problem is not even recognised by the users, who only notice the quality deterioration of the three-dimensional display, or the appearance of image ghosting.
• warnings may be given to the user based on the measured deviation, and/or display parameters may be modified to improve the quality of the three- dimensional image.
• the objective of the present invention is therefore to provide a display system and corresponding method that reduces or eliminates the above described problems related to prior art solutions to the greatest possible extent.
• a further objective of the invention is to provide a display system and method that allows the simple and efficient modification of the displayed image based on the current viewing direction of the user such that the quality of three-dimensional display is preserved to the greatest possible extent.
• Another objective of the invention is to provide a simple display system and method that can be implemented with low costs.
• Fig. 1 is a schematic drawing illustrating the problem to be solved by the system and method according to the present invention
• Fig. 2 is a schematic drawing illustrating the hardware components of a preferred embodiment
• Fig. 3 shows the structural block diagram of the core part of a preferred embodiment of the system. MODES FOR CARRYING OUT THE INVENTION
• the three-dimensional display system shown in Figs. 1 and 2 comprises a display surface 10 adapted for simultaneously displaying a left side image and a right side image, and further comprises image separation means 30 having a left side portion 31 adapted for separating, by means of polarization, the left side image for viewing by the left eye, and a right side portion 32 adapted for separating, by means of polarization, the right side image for viewing by the right eye.
• a polarizing layer 20 is disposed at a distance d in front of the display surface 10, said layer comprising first sub regions 21 having a first direction of polarization, and second sub regions 22 having a second direction of polarization different from the first one.
• the first and second sub regions 21 , 22 are disposed in an alternating manner, forming a pattern providing alternating polarization directions.
• the display surface 10 has first display regions 11 adapted for displaying the left side image and second display regions 12 adapted for displaying the right side image, the first and second display regions being arranged to correspond, respectively, to the first sub regions 21 and to the second sub regions 22.
• the first display regions 11 , as well as the second display regions 12 are implemented as one-pixel high horizontal pixel lines of the display surface 10, that is, a line-interleaved 3D display is applied.
• a sensor system is applied for detecting the current viewing direction determined by the image separation means 30, and thereby detecting the deviation of the current viewing direction from the optimum direction determined by the first display regions 11 , the second display regions 12, the first sub regions 21 and the second sub regions 22.
• optimum direction we mean a set of those viewing directions where the first display regions 11 exactly overlap with the first sub regions 21 , and also the second display regions 12 exactly overlap with the second sub regions 22.
• the set of optimum directions lies in a horizontal plane and the deviation is the angle between this plane and the current direction.
• the set of optimum directions is a straight line perpendicular to the centre of the display surface 10, the deviation being constituted by the angle between this line and the current direction.
• a position 40 illustrated in the drawing corresponds to one of the optimum viewing directions.
• the left eye of the user views the lines L corresponding to the left side image, that is, the first display regions 11 , through the left side portion 31 of the image separation means 30.
• This visibility and the exclusion of the lines corresponding to the right side image is provided by the identical direction of polarization of the first sub regions 21 of the polarizing layer 20 and of the left side portion 31.
• Identical polarization direction is illustrated by identical Crosshatch pattern.
• the lines R displaying the right side image correspond to the second display regions 12.
• the viewpoint of the user is displaced from position 40 to position 41 , in addition to the first display regions 11 (lines L) intended to constitute the left side image, also the second display regions 12 (lines) corresponding to the right side image become visible to the user through the first subregions 21 of the polarizing layer 20, to the extent that they make up half of the picture seen from position 41. In practice this will lead to the so-called "image ghosting", a phenomenon where to certain extent each eye is able to view the image intended for the other eye.
• the viewpoint of the user is moved to position 42, as it is visible on the figure, the right eye will be able to see almost exclusively the first display regions 11 corresponding to the left side image, that is, the images intended for the respective eyes are exchanged.
• the above described problem arises because the polarizing layer 20 is disposed in front of the display surface 10 at a distance (or gap) d.
• the present invention offers a solution to this problem.
• the user is informed of the necessity of moving the image separation means 30 in a direction reducing the deviation of the viewing direction from the optimum.
• the indication to the user may for instance include indicating that the user's viewpoint is outside the optimal or near-optimal region, or may include an indication of the direction of the required movement.
• the user receives a warning from the display system before the quality of 3D display would begin to deteriorate significantly.
• the image displayed on the display surface 10 is modified based on the detected deviation.
• a preferred way of modifying the displayed image involves computing the amount of image ghosting based on the detected deviation, and modifying the displayed image information to decrease or eliminate ghosting. Modifying the displayed image information preferably involves adding to the image intended for one eye the reduced-intensity negative of the image intended for the other eye.
• the above described preferred solution for ghost-image cancellation allows improving the properties of three-dimensional display for viewing directions that only slightly differ from the optimum direction.
• the deviation from the optimum direction reaches the position 41 exemplified in Fig. 1 , that is, each eye views the image intended for it and the image intended for the other eye to an equal extent, the image becomes "greyed” due to the above described ghost- image cancellation.
• This "greying" indicates to the user that the display surface 10 is being viewed from an incorrect viewpoint.
• modifying the displayed image involves a shifting of the first display regions 11 and the second display regions 12 over the display surface 10 by an identical amount in the same direction.
• the first and second display regions 11 , 12 adapted for displaying, respectively, the left and right side images are implemented as columns instead of lines, or they may also be arranged according to any arbitrary alternating pattern. An example of the latter may be a chequerboard-like arrangement.
• the problem of ghosting or interchanged left and right side images may be solved by shifting the first and second display regions along the display surface by a suitable extent determined by detecting the viewing direction.
• Such a shifting should be implemented such that the first and second display regions 1 , 12 become located to the greatest possible extent behind the first and second sub regions 21 , 22.
• a preferable solution may be modifying the displayed image by exchanging the first display regions 11 and the second display regions. 12 of the display surface 10.
• the first display regions 11 will correspond to the right eye
• the second display regions 12 correspond to the left eye.
• the arrangement shown in Fig. 2 constitutes a preferred embodiment where the viewing direction determined by the image separation means 30 is detected by optical sensors 50, 51 arranged on the display (implemented in this embodiment as a monitor).
• Direction detection is accomplished by transmitters 52, 53 arranged on the image separation means 30.
• Direction detection may for instance be performed according to the solution disclosed in WO 20 0/100511.
• the display surface 10 is implemented as the screen of a conventional LCD monitor, with the polarizing layer 20 being implemented as a polarization foil adhering to the LCD screen.
• a single sensor is sufficient, which may even be a simple USB web camera. Applying two sensors provides higher reliability.
• For detecting the viewing direction a single sensor is sufficient, which may even be a simple USB web camera. Applying two sensors provides higher reliability.
• For detecting the viewing direction a single sensor is sufficient, which may even be a simple USB web camera. Applying two sensors provides higher reliability.
• For detecting the deviation of the viewing direction from the optimum it is sufficient to detect the viewing
• Fig. 3 shows the schematic connection diagram of a control means 60 according to the present invention.
• the invention involves determining the deviation of the current viewing direction from the optimum direction utilizing the signals of the sensors 50, 51 , and modifying the displayed image applying the control means 60 as described above.
• the control means 60 is expediently implemented as a software module adapted for receiving and processing the signals of the sensors 50, 51 , and for modifying the image information displayed on the display surface 10 based on the results of signal processing.
• the invention may therefore be advantageously applied for commercially available line-interleaved 3D displays, which usually provide a stereo image of sufficient quality in a narrow vertical zone of 10-20 centimetres.
• the display system and method according to the invention allows that the user may be kept inside this zone, and/or that display parameters may be tuned and corrected taking into account the user's viewing position.
• the invention may be equally applied for systems operating with linear and circular polarization.
• the first and second display regions are statically assigned to the same respective eye (except for eventual interchanges), and thereby it is not required to alternate the displayed images.
• the human eye is unable to discern individual pixels located one under the other, and thereby the efficiency of ghost image cancellation is not deteriorated by the fact that the reduced-intensity negative of one of the images is displayed at the location intended for the other image, i.e. shifted by one line.
• the parallax problem arising from the presence of a distance d between the display surface 10 and the polarizing layer 20 may therefore be eliminated applying the above described solution.
• the invention may thereby be advantageously applied in conjunction with today's popular high-definition displays.
• the present invention is not limited to the preferred embodiments presented above in details but further modifications, variations, and further improvements are possible within the scope defined by the claims.
• image refers both to static and moving images.
• the sets of viewing directions corresponding to the optimum direction may extend along straight lines or in planes.

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• Engineering & Computer Science (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Theoretical Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Human Computer Interaction (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Testing, Inspecting, Measuring Of Stereoscopic Televisions And Televisions (AREA)

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Citations (6)

• 2012
  • 2012-01-06 HU HU1200013A patent/HUP1200013A2/hu unknown
• 2013
  • 2013-01-04 WO PCT/HU2013/000002 patent/WO2013102774A1/fr not_active Ceased

Patent Citations (8)

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