KR20110099526A - Method for converting two dimensional images into three dimensional images - Google Patents

Abstract

The present invention relates to a method for converting a 2D planar image into a 3D stereoscopic image. Specifically, a depth map is generated from a 2D planar image, a left image is copied, and a right side image is applied by applying a displacement map based on the depth map. The present invention relates to a method for generating and converting a two-dimensional plane image into a three-dimensional stereoscopic image by combining a left image and a right image having different parallax information. The method for converting a planar image into a stereoscopic image includes selecting a 2D image; Generating a depth map by extracting a motion vector from the 2D image; Generating a left image and a right image having different disparity information by applying a displacement map method based on the generated depth map; And generating a 3D image by combining a left image and a right image having different disparity information.

Description

Method for Converting Two Dimensional Images into Three Dimensional Images}

The present invention relates to a method for converting a 2D planar image into a 3D stereoscopic image. Specifically, a depth map is generated from a 2D planar image, a left image is copied, and a right side image is applied by applying a displacement map based on the depth map. The present invention relates to a method of generating and converting a 2D planar image into a 3D stereoscopic image by combining a left image and a right image having different disparity information.

In general, the production of a stereoscopic image may be performed by directly photographing and generating a stereoscopic image camera and converting a conventional 2D video image into a 3D stereoscopic image. Converting a two-dimensional video image to a three-dimensional stereoscopic image has the advantage that already produced video content can be utilized.

In order to convert a 2D planar image into a 3D stereoscopic image, a left image and a right image having different disparity information must be generated from a single video image. The left image can be generated from a two-dimensional plane image, but the right image with parallax with it should be made from the left image. In order to extract parallax information from a two-dimensional plane image, things such as motion information or vanishing point are generally used. The motion information may be used to generate a depth map that makes the image of the plane recognized as a space. In general, the conversion efficiency of a 2D planar image into a stereoscopic image may be determined by the generation speed and accuracy of such a depth map.

A known stereoscopic conversion method is a method of generating a depth map by painting each frame of a 2D planar image one by one with Photoshop. However, this method has a problem in that it is inefficient in terms of time and cost. As a prior art for solving such a problem, there is a patent application No. 2008-0065889 "A stereoscopic image generating apparatus and method thereof from a two-dimensional image using a net map". The prior art receives a two-dimensional image file and displays a superimposed with the net map, edits the net map by receiving the shape and depth information of the net map from the user, and configures the two-dimensional image according to the shape and depth information of the net map Disclosed is a stereoscopic image generating method of calculating relative depth information of pixels and generating a stereoscopic image file using depth information of a two-dimensional image.

The prior art does not disclose a specific method of obtaining depth information necessary for generating a stereoscopic image. In order to generate a 3D stereoscopic image from the 2D image, a quick and accurate depth map must be generated.

The present invention is to solve the above problems with the prior art has the following object.

An object of the present invention is to provide a method for quickly and accurately converting a two-dimensional planar image into a three-dimensional stereoscopic image.

According to a preferred embodiment of the present invention, a method for converting a planar image to a stereoscopic image includes selecting a two-dimensional image; Generating a depth map by extracting a motion vector from the 2D image; Generating a left image and a right image having different disparity information by applying a displacement map method based on the generated depth map; And generating a 3D image by combining a left image and a right image having different disparity information.

According to another suitable embodiment of the present invention, the method further includes correcting the depth map.

According to another suitable embodiment of the present invention, the correction of the depth map is made by generating an object matte through image tracking.

According to another suitable embodiment of the present invention, the correction of the depth map is made by a method of image processing after contrast with the original image.

According to another suitable embodiment of the present invention, the parallax information by the displacement map method is made based only on the horizontal parallax value.

The method according to the present invention has an advantage of generating a depth map quickly and accurately to convert a 2D image into a 3D stereoscopic image. In particular, the method according to the present invention has the advantage that the application is simple and the stereoscopic effect can be increased in the case of a two-dimensional video having a large number of continuous images or action scenes.

1 schematically shows a conversion method according to the invention.

Hereinafter, the present invention will be described in detail with reference to the embodiments set forth in the accompanying drawings, but the embodiments are provided for clarity of understanding and the present invention is not limited thereto.

1 schematically shows a conversion method according to the invention.

Method for converting a two-dimensional image to a three-dimensional stereoscopic image according to the present invention comprises the steps of selecting a two-dimensional image; Generating a depth map by extracting a motion vector from the 2D image; Generating a left image and a right image having different disparity information by applying a displacement map method based on the generated depth map; And generating a 3D image by combining a left image and a right image having different disparity information.

Specifically, as shown in Figure 1, the method according to the invention comprises the steps of selecting a two-dimensional image (S11); Generating a first depth map using a motion vector from the 2D image (S12); Correcting the primary depth map (S13); Correcting the corrected first depth map by contrasting the original image and completing a final depth map (S14); Generating a left image and a right image having different disparity information by applying a displacement map method based on the depth map (S15); And generating a 3D stereoscopic image by combining the generated left image and the right image (S16).

The two-dimensional image may be any form known in the art including a movie or game image as any two-dimensional image that has already been made or may be made in the future. The two-dimensional image selected to be converted to the stereoscopic image may become the original image and at the same time the left image. In the present specification, the left image refers to any one of two images made to have a parallax for generating a stereoscopic image.

A first depth map may be generated from the selected 2D image. The depth map is a map representing a three-dimensional distance difference between objects existing in the image, and each pixel representing the image may have a value ranging from 0 to 255. In general, bright colors mean they are on the near side with large values. Depth maps can be created from motion vectors. The motion vector is a key element in the motion estimation process, and according to the H.264 / MPEG-4 AVC standard, it provides an offset from the decoded screen coordinates to the reference screen coordinates. It is defined as a two-dimensional vector used for mutual prediction. Various algorithms can be used to extract motion vectors or motion information. For example, there are algorithms that use optical flow, which is easy to grasp the motion of the entire image by extracting motion information for each block, and a Lucas-Kanade-Tomasi Tracker (KTL) algorithm. The method using the optical flow has the advantage that the algorithm is simple and the MPEG video file has the advantage of easy application because the motion data using the optical flow is embedded in the video data, but it is difficult to extract the accurate motion information because it is sensitive to noise. On the other hand, the KLT tracking algorithm can extract robust and precise motions against noise, but has the disadvantage of complicated algorithm. In the case of the 3D stereoscopic image conversion method according to the present invention, any algorithm may be applied, but a method using an optical flow may be preferably applied. Optical flow refers to the relative movement of objects, surfaces, and edges in a visual scene caused by relative movement between the observer (eye or camera) and the scene. Optical flow techniques such as motion detection, object segmentation, focus of time-to-collision and extension calculations, motion complementary encoding, and stereoscopic mismatch measurements utilize object surfaces and edged optical flows. Methods of extracting motion vectors using optical flow are known in the art and can be used to generate depth maps by extracting motion vectors using programs such as The Foundry Nuke v6.0 or plug-in Furnace4.2, for example. In detail, a motion vector may be extracted using F_vectorgenerator in a program such as the plug-in Furnace 4.2 of thefoundry, and the extracted motion vector may be recognized as a vector value of F_depth to generate a depth map.

The presented method of extracting the program or motion vector and the method of generating the depth map by way of example are various programs can be used, and the depth map can be generated in various ways, and the present invention is not limited by the specific program or method.

The first-depth depth map created by extracting the motion vector from the algorithm using optical flow has the disadvantage of being sensitive to noise while lacking sophisticated motion information. In addition, the foreground and background objects have a disadvantage in that they can be recognized. In order to make up for this drawback, the primary depth map, which is created, is inspected and corrected when an error is found. If it is determined that an error has occurred, an object matte is generated by tracking the movement of the object through object tracking. The generated object mat is added to the primary depth map to modify the depth information to generate the secondary depth map. If necessary, the first depth map may be modified by extracting the actual 3D spatial value through 3D tracking. The generation of such a second depth map may be automatically performed through a program. For example, secondary depth maps can be created through programs such as the Imagineer System Mokey, Mocha, Motor or Pixelfarm PFTrack. Secondary depth maps do not have to be generated nor do they have to be formed according to the method presented above. Secondary depth maps can be made when correction of errors is required and can be made in a variety of ways.

Since the second depth map contains only depth information of the original image, the aesthetic part, which is the essence of the image, may be faded. For example, it may not contain color change for aesthetic expression and may have errors due to damage of the original image. Such problems may be corrected by performing image processing by contrasting an image based on a depth map with an original image.

Depth information may be obtained from perspective information of the still image without motion information in the depth map generation process. Alternatively, a method of obtaining depth information by giving depth to the entire screen, obtaining depth information by a 24-bit RGB value, or analyzing a depth property of an object and giving a gray level by similarly assuming a three-dimensional image may be used. Can be. Hough transform may be used to obtain depth information from perspective information. In detail, a linear component in an image is extracted using a Hough transform, and an intersection point of major linear components may be regarded as a vanishing point. And the depth information of the still image can be obtained from the perspective determined from the vanishing point. Depth information of a still picture may be obtained through various methods including the method described above, and may be added to the depth map.

When the depth map is generated, parallax information may be generated based on the depth map. The parallax information can be obtained by the equation as follows.

Parallax = M × {1- (Depth Value / 256)} ------ Equation (1)

An image having parallax information may be generated from the depth map by applying the above equation. A displacement map may be applied to generate an image with parallax. Displacement maps can be created by displacement mapping. Specifically, the displacement map method is used to generate the effect that the texture function is moved along the local surface vertical vector by the value of the texture function evaluated at each point on the surface on the textured surface. Stands for Computer Graphics Technology. The displacement map method generally includes a machining map method used to adjust the displacement strength and the displacement direction is generally a direction perpendicular to the local surface. For the displacement map a micropolygon-based Reyes algorithm or similar approach may be used. Various types of programs have been developed for applying the displacement map method, and according to the method according to the present invention, a displacement map may be made by employing various types of programs developed or to be developed in the future. For example, a displacement map can be created and a parallax image can be made by a program such as Adobe's AfterEffects CS4.

The depth map is the basis for the generation of the parallax image by the displacement map method. In general, the depth map includes horizontal and vertical movements, and when the vertical movement is converted into parallax, a phenomenon such as dizziness may occur. Therefore, vertical motion must be converted to horizontal parallax. Therefore, substantially only horizontal parallax can be used for generation of parallax images. On the other hand, the maximum parallax value is determined and horizontal or vertical movement beyond the threshold defined in the depth map should be converted to the maximum parallax value.

In this manner, when the parallax information is generated by applying the displacement map based on the depth map, the parallax image may be generated. The parallax image can be made into the left image and the right image, and according to the equation given by Equation (1) above, the left image is shifted to the left by (parallax / 2) and the right image is shifted to the right by (parallax / 2) Can be made in the form of

The left and right images with parallax may be reproduced as stereoscopic images by, for example, a 3D imaging device such as a RealID system, a Dolby system, or an XpanD system. Or it can be played on a computer screen capable of 3D implementation.

The method of converting a 2D image into a 3D stereoscopic image according to the present invention described above has an advantage that the conversion is performed quickly and accurately. In particular, the method according to the present invention has the advantage that the application is simple and the stereoscopic effect can be increased in the case of a two-dimensional video having a large number of continuous images or action scenes.

Those skilled in the art will be able to make various modifications and modifications without departing from the technical spirit of the present invention with reference to the presented embodiments. The invention is not limited by these variations and modifications, but is only limited by the scope of the appended claims.

S11: 2D image selection S12: Depth map generation S13: Depth map correction
S14: Final depth map completion S15: Left image and right image generation
S16: stereoscopic image generation

Claims (5)

Selecting a two-dimensional image;
Generating a depth map by extracting a motion vector from the 2D image;
Generating a left image and a right image having different disparity information by applying a displacement map method based on the generated depth map; And
A method of converting a planar image into a stereoscopic image, comprising: generating a 3D image by combining a left image and a right image having different parallax information. The method of claim 1, further comprising correcting the depth map. The method of claim 2, wherein the correction of the depth map is performed by generating an object matte through image tracking. The method of claim 2, wherein the correction of the depth map is performed by a method of image processing after contrast with an original image. The method of claim 1, wherein the disparity information by the displacement map method is generated based only on a horizontal disparity value.

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