WO2010147451A1

WO2010147451A1 - An online orthogonal projection system

Info

Publication number: WO2010147451A1
Application number: PCT/MY2010/000091
Authority: WO
Inventors: Hock Woon Hon; Yen San Yong
Original assignee: Mimos Berhad
Priority date: 2009-06-15
Filing date: 2010-06-02
Publication date: 2010-12-23

Abstract

An online orthogonal projection system (100) is provided that includes at least two imaging input means (103, 105), a storage means (101), wherein the storage means (101) includes radiance, light intensity and geometric distortion factors, an image registration module (107), wherein the at least two imaging inputs (103, 105) are fed into the image registration module (107), at least two geometric transform modules (109, 111), wherein output from the image registration module (107) are fed into the at least two geometric transform modules (109, 111), wherein the storage means (101) is used to process geometric transformation, at least two radiance transform modules (113, 115), wherein output from the geometric transform modules (109, 111) are fed into the at least two radiance transform modules (113, 115), wherein the storage means (101) is used to process radiance transformation and an image splitter (117), wherein the image splitter (117) decomposes a resulting composite image into at least two component images to be displayed in a first projecting device (119) and a second projecting device (121), wherein a combination of both projections result in a final composite image, wherein the system is used with at least two projectors (119, 121) that are disposed such that both projectors (119, 121) are at a predetermined angle range of 85° to 95° from each projector.

Description

AN ONLINE ORTHOGONAL PROJECTION SYSTEM

FIELD OF INVENTION

The present invention relates to an online projection system, more particularly relates to an online orthogonal projection system using two projecting devices.

BACKGROUND OF INVENTION

Complex multiple projectors require equally complex configuration setup especially when more than one screen is used and the projection is wide and continuous. Multiple screen projection usually involves tedious set up and calibration process during the setup and even more so when the configuration needs to be relocated. The problem is further compounded when it involves duplicated overlapping projection region between 2 videos from two projectors.

U.S. 6755537 describes a method for globally aligning multiple projected images by forming a cluster from a set of projectors. It is known that each projector in the set includes a projector sub-system in a relationship to a camera sub-system. This method is described as using a communications sub-system to broadcast ready messages. However, the drawbacks of this method are that the end image can only be received by sequentially receiving projections from the set of projectors used. This method can be error-prone if the communication sub-system receives a faulty ready message. The resulting image will be skewed if any communication message is broadcast erroneously as the system is completely dependent on a centralized managing system. Additionally, image and light uniformity may not also be consistent across individual display portions in a composite display. Light intensity can vary within each individual portion of a composite display resulting in irregularities in brightness. Overlap that can happen when multiple projections are used tends to cause some portions of the end projection to be brighter than the rest of the image.

The existing prior art has not addressed these issues where there is a need for multiple projections to be produced without all the issues that have been highlighted above and in a dependable manner.

SUMMARY OF INVENTION

Accordingly there is provided an online orthogonal projection system, the system includes at least two imaging input means, a storage means, wherein the storage means includes radiance, light intensity and geometric distortion factors, an image registration module, wherein the at least two imaging inputs are fed into the image registration module, at least two geometric transform modules, wherein output from the image registration module are fed into the at least two geometric transform modules, wherein the storage means is used to process geometric transformation, at least two radiance transform modules, wherein output from the geometric transform modules are fed into the at least two radiance transform modules, wherein the storage means is used to process radiance transformation and an image splitter, wherein the image splitter decomposes a resulting composite image into at least two component images to be displayed in a first projecting device and a second projecting device, wherein a combination of both projections result in a final composite image, wherein the system is used with at least two projectors that are disposed such that both projectors are at a predetermined angle range of 85° to 95° from each projector.

There is also provided a method of geometrically transforming images and transforming radiance levels of images, the method includes the steps of registering at least two images in an online orthogonal projection system, geometrically transforming the at least two images using previously stored radiance, light intensity and geometric distortion factors in a storage means, transforming radiance levels of the at least two images using previously stored radiance, light intensity and geometric distortion factors of storage means and decomposing the at least two images to be displayed in the first and second projecting devices. There is further provided a method of configuring an online projection system, the method includes the steps of calculating curve information for a curved background, ensuring that at least two projecting devices are used, wherein the at least two projecting devices are at a right angle to each other, decomposing a composite image into a horizontal and a vertical component, wherein the composite image is projected from the at least two projecting devices, applying the calculated curve information to compensate for radiance and light intensity for a first projecting device, mirroring calculated radiance and light intensity compensation for a second projecting device, pre-distort an image with the calculated curve information in first projecting device, mirroring the pre-distorted calculation for the second projecting device and storing radiance, light intensity and geometric distortion factors in a storage means.

The present invention consists of several novel features and a combination of parts hereinafter fully described and illustrated in the accompanying description and drawings, it being understood that various changes in the details may be made without departing from the scope of the invention or sacrificing any of the advantages of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, wherein:

Figure 1 is a diagram illustrating an embodiment of an online orthogonal projection system;

Figure 2 is a flowchart showing the steps taken in an embodiment of the present invention to configure an online projection system;

Figure 3 is a diagram illustrating 2 projecting devices that are arranged at a right angle to each other in an embodiment of the present invention;

Figure 4 is a sample of a curve calculation using an equation in an embodiment of the present invention;

Figure 5 is a diagram illustrating an embodiment of an orthogonal projection using two projecting devices;

Figure 6 is a diagram illustrating decomposed horizontal and vertical components of a projection in an embodiment of the present invention;

Figure 7 is a diagram illustrating a top-down view showing audience location in an embodiment of the present invention;

Figure 8 is a diagram illustrating an analysis of vertical and horizontal components of an embodiment of the present invention; Figure 9 is a diagram illustrating a graphical representation of radiance reduction in an embodiment of the present invention;

Figure 10 is a diagram illustrating an unwrapped equivalent of a curved screen used in an embodiment of the present invention;

Figure 11 is a diagram illustrating radiometric pre-distortion from projecting device 1 and projecting device 2 in an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to an online orthogonal projection system. Hereinafter, this specification will describe the present invention according to the preferred embodiments of the present invention. However, it is to be understood that limiting the description to the preferred embodiment of the invention is merely to facilitate discussion of the present invention and it is envisioned that those skilled in the art may devise various modifications and equivalents without departing from the scope of the appended claims.

The following detailed description of the preferred embodiment will now be described in accordance with the attached drawings, either individually or in combination.

Figure 1 depicts an embodiment of the invention wherein an online orthogonal projection system (100) includes at least two imaging input means (103, 105) that is fed into an image registration module (107) wherein the output of said image registration module (107) is split into two outputs and further fed into at least two geometric transform modules (109,111 ). A further description of a method of how the outputs are split is described further on in the description. A storage means (101) is used to store radiance, light intensity and geometric distortion factors where these factors are included to pre-calculate curve information. The radiance, light intensity and geometric distortion factors are factored into these geometric transform modules (109, 111).

The output from the geometric transform modules (109,111 ) is fed into at least two radiance transform modules (113,115) and the output of the same is further fed into an image splitter (117). The storage means (101 ) as described earlier is factored into these radiance transform modules (113,115). The method of the same will be discussed later in this section. The image splitter (117) further decomposes a resulting composite image into at least two component images to be displayed in a first projecting device (119) and a second projecting device (121 ), wherein a combination of both projections result in a final composite image projected onto at least two projecting devices (119, 121 ) such as projector 1 (119) and projector 2 (121 ) as shown in Figure 1. Projector 1 (119) and projector 2 (121 ) are placed at a predetermined angle, within the range of 85° to 95°, to each other using a metal bar (301 ) with a scale in this system (100) as seen in Figure 3.

A method of geometrically transforming images and transforming radiance of the described system (100) in Figure 1 begins with the steps of registering at least two images in an online orthogonal projection system (100) and further geometrically transforming the at least two images using previously stored radiance factors, light intensity factors and geometric distortion factors in a storage means (101 ). The output of said image registration module (107) is split into two outputs in order to split a large width to length ratio into a relatively smaller ratio. For example in this embodiment, a panoramic image has a rectangular image with a larger width to length ratio (X:Y) which is 8:3, where this display is used for extended desktop for more horizontal space. This is also applied for panoramic image where the panoramic image is divided into two parts equally. If the panoramic image has a width to length ratio of X:Y, the two parts of the image would have ratio of (X/2) : Y each. The two images are then fed as input into the geometric transform module A (109) and geometric transform module B (111 ) respectively.

The image registration module (107) registers an area of overlap wherein both geometric transform modules (109,111) have an overlap of a same part of an image. The area of overlap may be up to 15 % of total area of an original image. The following step is to transform radiance levels of the at least two images using previously stored radiance, light intensity and geometric distortion factors of storage means (101 ) and decompose the at least two images to be displayed in the first and second projecting devices (119,121 ).

In order to use the system (100) as described previously, a method of configuring an online projection system (100) is first conducted. The method begins with the step of calculating curve information for a curved screen. The curve screen is placed in front of two walls that are used in an online projection system (100) where at least two projecting devices (119,121 ) must be arranged such that the two projecting devices (119,121 ) are at a right angle to each other as seen in Figure 3. This configuration enables each of the projecting devices (119,121 ) to be projected to each side of a wall. The curve can then be calculated by considering factors such as radius, radian, height and hypotenuse. A sample curve calculation is done by plotting curve against distance as seen in Figure 4. Distance between borders of the two walls is also calculated.

The orthogonal projection is shown in Figure 5 where both projecting devices (119,121) are at a right angle. This right angle placement causes the distortion to be compensated by the following method. The projection will appear to be as shown in Figure 5 when the screen is placed in front of a corner of two walls. The projection is then decomposed into a horizontal and a vertical component. The curvature of the screen from the view of both projecting devices (119, 121 ) can be seen in Figure 6. A vertical component is projected from the first projector (119) and a horizontal component is projected from the second projector (121). A top-down view showing audience location where wide-area content can be displayed in the screen is shown in Figure 7. Images from the vertical and horizontal components are analyzed and radiance reduction is applied to an image according to its relative position as shown in Figure 8. As seen in figure 8, image intensity and radiance is matched between 1 and 3 as well as 2 and 4. These are complementary pairs in terms of image processing. The image processing method is as describe below.

The two images from the first projector (119) and the second projector (121) are respectively labeled as image 1 and image 2 as seen in Figure 5. In image 1 , the overlapping region appears on the left side of image 1. For image 2, the overlapping region appears on the right side of image 2. For both these images, the radiance of each image is reduced according to the graph in Figure 9. For example, the radiance of image 1 reduces according to the graph in Figure 9 from one edge of the overlapping region to the opposite edge of the overlapping region. The same method is applied in an opposing manner for image 2, wherein the radiance is reduced from one edge of the overlapping region to the opposite edge. The radiance is reduced by adjusting the brightness of the images 1 and 2. In image processing, intensity of both images is adjusted according to the graph in Figure 9 and 10.

A graphical representation of radiance reduction is shown in Figure 9. The radiance reduction is done by applying an equation representing curvature of the screen as described earlier. The curvature is as seen in Figure 4. The equation of the curvature is as follows:

Curve, y = (r² + b²f - r

Accordingly, on the second projecting device (121 ), the curvature is symmetric to the first curvature, but curving at a different direction wherein when the two curves are put together, the summation of the radiance at any point would equal to unity as shown in Figure 10. A graphical representation of the two projecting device images is shown in Figure 11 , where grey areas (201 , 204) represent constant radiance and light intensity. Shaded areas (202,203) show a gradual change in light intensity and this gradient represents the amount of light intensity needed to be reduced based on location. The gradient of radiance and light intensity corresponds to curvature of screen as described in the earlier section. The curve information that has been obtained is further applied to compensate for radiance and light intensity for the first projector (119) (as seen in Figure 1 ). This same step is then mirrored for the second projector (121 ).

Furthermore, geometric transformation compensation is done based on the same principle as the radiance and light intensity reduction principle. The images from both projecting devices (119,121 ) are pre-distorted such that the warping distortion would compensate the distortion introduced by an irregular distance of the curved screen. These derived radiance, light intensity and geometric distortion factors are then stored in the storage means (101 ) to be retrieved when the online projection system (100) is configured and operational.

It is appreciated that a person skilled in the art would be aware that the present invention can be used for, but not restricted to, applications such as video, movie, camera and computer projections.

Claims

1. An online orthogonal projection system (100), the system (100) includes: i. at least two imaging input means (103, 105); ii. a storage means (101 ), wherein the storage means (101 ) includes radiance, light intensity and geometric distortion factors; iii. an image registration module (107), wherein the at least two imaging inputs (103, 105) are fed into the image registration module (107); iv. at least two geometric transform modules (109, 111 ), wherein output from the image registration module (107) are fed into the at least two geometric transform modules (109, 111 ), wherein the storage means

(101 ) is used to process geometric transformation; v. at least two radiance transform modules (113, 115), wherein output from the geometric transform modules (109, 111) are fed into the at least two radiance transform modules (113, 115), wherein the storage means (101 ) is used to process radiance transformation; and vi. an image splitter (117), wherein the image splitter (117) decomposes a resulting composite image into at least two component images to be displayed in a first projecting device (119) and a second projecting device (121 ), wherein a combination of both projections result in a final composite image, wherein the system is used with at least two projectors (119, 121 ) that are disposed such that both projectors (119,121 ) are at a predetermined angle range of 85° to 95° from each projector.

2. The system (100) as claimed in claim 1 , wherein the two projectors (119,121 ) are disposed at a 90° angle to each other with the use of a metal bar (301 ) with a scale.

3. A method of geometrically transforming images and transforming radiance levels of images, the method includes the steps of : i. registering at least two images in an online orthogonal projection system

(100); ii. geometrically transforming the at least two images using previously stored radiance, light intensity and geometric distortion factors in a storage means (101 ); iii. transforming radiance levels of the at least two images using previously stored radiance, light intensity and geometric distortion factors of storage means (101 ); and iv. decomposing the at least two images to be displayed in the first and second projecting devices (119,121 ).

4. A method of configuring an online projection system (100), the method includes the steps of: i. calculating curve information for a curved background; ii. ensuring that at least two projecting devices (1 19) are used, wherein the at least two projecting devices (1 19) are at a right angle to each other; iii. decomposing a composite image into a horizontal and a vertical component, wherein the composite image is projected from the at least two projecting devices (119); iv. applying the calculated curve information to compensate for radiance and light intensity for a first projecting device (119); v. mirroring calculated radiance and light intensity compensation for a second projecting device (121 ); vi. pre-distort an image with the calculated curve information in first projecting device (1 19); vii. mirroring the pre-distorted calculation for the second projecting device

(121 ); and viii. storing radiance, light intensity and geometric distortion factors in a storage means (101 ).

5. The method as claimed in claim 4, wherein the curve can be calculated by considering factors such as radius, radian, height and hypotenuse.

6. The method as claimed in claim 4, wherein the curvature of projector 2 (121 ) is symmetric to the curvature of projector 1 (119).

7. The method as claimed as claim 4, wherein the calculated curve information is such that summation of radiance at any point of a curve must be equal to unity.