Classifications

• • 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
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T7/00—Image analysis
  • G06T7/50—Depth or shape recovery
  • G06T7/55—Depth or shape recovery from multiple images
  • G06T7/593—Depth or shape recovery from multiple images from stereo images
  • G06T7/596—Depth or shape recovery from multiple images from stereo images from three or more stereo images
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T2207/00—Indexing scheme for image analysis or image enhancement
  • G06T2207/10—Image acquisition modality
  • G06T2207/10004—Still image; Photographic image
  • G06T2207/10012—Stereo images
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T2207/00—Indexing scheme for image analysis or image enhancement
  • G06T2207/20—Special algorithmic details
  • G06T2207/20088—Trinocular vision calculations; trifocal tensor
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
  • G06T2207/00—Indexing scheme for image analysis or image enhancement
  • G06T2207/30—Subject of image; Context of image processing
  • G06T2207/30181—Earth observation

Definitions

• the present invention relates to a method for displaying a virtual image of three dimensional objects in an area using stereo recordings of the area for storing a pixel and a height for each point of the area.
• mapping It is previously known within mapping to generate and store a pixel and a height for each point on the ground. Resolutions that can be used are for example one meter or one decimetre on ground.
• the two data stored for each point describe texture and height in that point and referred to a suitable coordinate system.
• When producing these data it is necessary to be in possession of two different image recordings from somewhat different positions but generally rather close to the vertical line. These images can be displayed as orthophotos.
• Stereo recording is per se previously known and it can for example be referred to US patent 6 175 648 disclosing a multi image stereo processing method. A plurality of measurements are chosen or weighted into a common data base. Methods of obtaining height information from stereo recordings are inter alia discussed in our patent application PCT/EP2007/056780 filed April 4, 2007.
• An object with the present invention is to obtain a method enabling displaying of vertical surfaces or even slightly downwards and inwards inclined surfaces.
• the object of the invention is obtained by a method characterized in that stereo recordings from at least three different stereo recordings of different solid angels are used to cover the area, that for each different solid angel at least one data base comprising data about texture and height pixel point wise is established, and that data for displaying the virtual image are combined from the different data bases in dependence of the direction in which the virtual image is to be displayed.
• stereo recordings from at least three different stereo recordings of different solid angels are used to cover the area, that for each different solid angel at least one data base comprising data about texture and height pixel point wise is established, and that data for displaying the virtual image are combined from the different data bases in dependence of the direction in which the virtual image is to be displayed.
• the method data for displaying the virtual image for a solid angle are combined from databases connected to two or more stereo recordings.
• data for displaying the virtual image is chosen from the data base connected to the stereo recording closest in angle to the direction in which the virtual image is to be displayed.
• three different stereo recordings are used having solid angles projections in a ground plane separated substantially 120 degrees from each other to cover an azimuth of substantially 120 degrees each and that data are fetched from the data bases covering an azimuth that the projection of the direction in the ground plane of the virtual image to be displayed points out.
• the use of three stereo recordings enables to keep down the number of data at the same time as the area to be displayed can be covered from all directions in question.
• the different stereo recordings could be recorded about 30 degrees from a vertical line perpendicular to the ground plane.
• the number of data bases and different stereo recordings are increased according to favourable developments of the method.
• four different stereo recordings are used having solid angles projections in a ground plane separated substantially 90 degrees from each other to cover an azimuth of substantially 90 degrees each and that data are fetched from the data base covering an azimuth that the projection of the direction in the ground plane of the virtual image to be displayed points out.
• the different stereo recordings could be recorded about 45 degrees from a vertical line perpendicular to the ground plane.
• an additional stereo recording substantially perpendicular to a ground plane is used to cover a circular solid angel from which data base data are fetched for directions of the virtual image to be displayed perpendicular to or almost perpendicular to the ground plane.
• data from more than one data base could be interpolated close to transitions between different stereo recordings. This could strengthen the image quality in the part of the stereo recordings having lower image quality.
• the heights are expressed as angular heights.
• Another variant of the method is to store information about recording angle in the data bases in addition to texture and height information.
• Figure 1 schematically illustrates image recording of an area.
• Figure 2 schematically illustrates stereo recording.
• Figure 3 illustrates a first example of stereo recordings to be used according to a method for displaying a virtual image of three dimensional objects in accordance with the invention.
• Figure 4 illustrates a second example of stereo recordings to be used according to a method for displaying a virtual image of three dimensional objects in accordance with the invention.
• Figure 5 illustrates a third example of stereo recordings to be used according to a method for displaying a virtual image of three dimensional objects in accordance with the invention.
• Figure 6 schematically illustrates a first example of data bases suitable for the stereo recording example of figure 3.
• Figure 7 schematically illustrates a second example of data bases suitable for the stereo recording example of figure 3.
• Figure 8 is a flow chart showing an example how to process information.
• an area 1 with buildings 2a- 2f are recorded from an aircraft 3 by means of a recording equipment 4.
• a recording equipment 4 any other movable carrier could be used such as a satellite, a land vehicle or a watercraft. So the recording can be effected from air, ground or sea and even directly from ground recording the ground for example by the activity of a human being.
• FIG 2 stereo recording of an area is illustrated.
• An image capturing unit 5 is comprised. At a first time this image capturing unit is located at a first position 5 a so as to capture an image of an area 6a. At a second time, the image capturing unit is located at a second position 5b so as to capture an image of an area 6b. In this way a plurality of at least partly overlapping images each covering at least a part of the area
• the 2 can be regarded to comprise a plurality of image capturing sub units 5a and 5b fixed mounted in relation to each other.
• the images of the areas 6a and 6b captured by the image capturing sub units 5 a, 5b are then in one example captured at the same time.
• FIG 3 a first example of stereo recordings to be used according to a method for displaying a virtual image of three dimensional objects in accordance with the invention is shown.
• the area 1 is stereo recorded from at least three directions.
• the recordings could be from north illustrated by arrow 7 and ⁇ 120 degrees angle in azimuth illustrated by arrows 8 and 9.
• the three recordings is proposed to deviate about 30 degrees from a vertical line perpendicular to the ground plane of the area 1.
• a data base is set up comprising at least data about texture and height for each point in the area 1. Introduction of data bases in this way based upon stereo recordings in three different solid angles results in that all house fronts are visible in one or more of the data bases.
• each displayed pixel are chosen from the data base closest in angle to the direction of display of the three data bases. If, for example, a viewer looks straight downwards all three data bases will be used as input data in "a piece of cake" each piece of about 120 degrees of the displayed image. If the viewer looks straight south, data is only fetched from the data base recorded from north according to the example given above.
• the recording angle and the angles of the data bases can be the same, but it is also possible to operate with angles that more or less differ between recording angle and data based angles.
• Figure 4 shows a second example of stereo recordings to be used according to a method for displaying a virtual image of three dimensional objects in accordance with the invention.
• the area 1 is stereo recorded from four directions illustrated by arrows 10-13 so that the ground plane are divided into four sections covering 90 degrees each in azimuth.
• a data base is set up and used in a way corresponding to the process described with reference to figure 3.
• figure 5 proposed to use stereo recordings from five directions using five separate databases, hi this case four of the directions are similar to those described in figure 4 and denoted with arrows 10-13. in addition to these four directions a fifth direction 14 is used recorded close to a direction perpendicular to the ground plane and covering a circular solid angle. This last mentioned recording is similar to the process of capturing ortho photo images. When displaying an image the fifth recording can be used to cover an angle of about 30 degrees upright from the ground plane. A suitable recording elevation angle for the other four recordings could be about 45 degrees.
• further data bases could be used.
• nine data bases could be used, hi such a case one data base could be recorded from straight above, while four data bases could be recorded at a first elevation angle of for example 25 degrees and another four data bases at a second elevation angle of for example 45 degrees, the recording of the four data bases at each elevation angle being separated in azimuth by about 90 degrees.
• an angle deviating from a vertical line of about 30 degrees is proposed.
• the corresponding angle is proposed to be about 45 degrees.
• These angels are only to be seen as proposals and it is possible to choose any other suitable angels.
• the angle could amount to 90 degrees and even more, resulting in that vertical surfaces, such as house walls, are optimally imaged in a straight forward direction.
• FIG 6 a first example of data bases for a three direction stereo recording is schematically shown suitable for the stereo recording example discussed with reference to figure 3.
• Each recording direction is allotted a date base 15, 16 and 17, respectively.
• Each such data base contains at least information regarding position 18 of a pixel point, the texture 19 of the pixel and height information 20 for the pixel point.
• the height does not need to be expressed explicitly but can be expressed as an angular height, for example a 30-degrees-height.
• the angular height in this connection can be defined as the height project to the focal plane of the camera in the projection direction of the database.
• Figure 7 proposes a slight different set of data bases suitable for the stereo recording example discussed with reference to figure 3. In this case information about recording angle 21 is added to the databases 15-17.
• the data stored in data bases as schematically shown in figures 6 and 7 are also available as information usable to calculate measures of objects, such as distances, areas and volumes.
• a flow chart is shown schematically illustrating, as an example, how information can be processed. The process is initiated from a start block 22. First of all it is ensured that stereo recordings needed for the final image presentation is available. Block 23 provides these stereo recordings. Stereo recording has already been discussed with reference to figure 2 and figures 3-5 suggest suitable recording directions to cover an area to be shown.
• Block 24 sets the number n of stereo recordings to be processed and the minimum number is set to three.
• a choice of data base takes place.
• the data base is chosen that has been recorded in a direction closest in angle to the direction in which the virtual image is to be displayed.
• a so called viewer could be used.
• Such a viewer has knowledge about the data bases available and that can be used.
• this viewer calculates the respective data bases to be used for the different areas in the image to be displayed.
• particular algorithms can be used to smooth out the transitions in the image.
• interpolation One way of doing this is interpolation.
• the viewer carries out the usual calculations in connection to image displaying. So the same three dimensional effects that are carried out today are to be considered. This means that when you move virtually and look in different directions you can perceive the three dimensional effects and that different objects in the image are hidden behind each other.
• the information from the chosen data base is displayed as an image on a screen of a suitable display device, hi case that the direction of the virtual image to be displayed is changed, that is a new angle is desired, see block 28, the process is repeated from the input of block 26. Otherwise the process is stopped, see block 29.

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• Engineering & Computer Science (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Computer Vision & Pattern Recognition (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Theoretical Computer Science (AREA)
• Processing Or Creating Images (AREA)
• Testing, Inspecting, Measuring Of Stereoscopic Televisions And Televisions (AREA)
• Controls And Circuits For Display Device (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=39512781

Family Applications (1)

Country Status (7)

Families Citing this family (5)

Citations (1)

Family Cites Families (15)

• 2007
  • 2007-12-27 EP EP07445047A patent/EP2076055B1/en active Active
• 2008
  • 2008-12-22 AU AU2008344047A patent/AU2008344047B2/en active Active
  • 2008-12-22 CA CA2710746A patent/CA2710746C/en active Active
  • 2008-12-22 JP JP2010540613A patent/JP5511681B2/ja active Active
  • 2008-12-22 WO PCT/SE2008/000739 patent/WO2009084993A1/en not_active Ceased
  • 2008-12-22 US US12/810,352 patent/US9338423B2/en active Active
• 2010
  • 2010-07-26 NO NO20101065A patent/NO340724B1/no unknown

Patent Citations (1)

Non-Patent Citations (2)

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