Innovations in reconstruction and rendering of panoramic video are described. For example, a view-dependent operation controller of a panoramic video playback system receives an indication of a view direction for an application and, based at least in part on the view direction, identifies a section of a picture of panoramic video in an input projection. The view-dependent operation controller limits operations of a color converter, video decoder, and/or streaming controller to the identified section. In this way, the panoramic video playback system can avoid performing operations to reconstruct sections of the picture of panoramic video that will not be viewed. As another example, a mapper of a panoramic video playback system re-projects at least some sample values in an input flat projection towards a center location for a view direction, producing an output flat projection, which an application can use to generate one or more screen projections.

An electronic apparatus is provided. The apparatus includes a storage and a processor configured to convert an original image to a spherical image, to acquire a plurality of two-dimensional (2D) images corresponding to a respective plurality of points on the spherical image by projecting the spherical image onto a plane with reference to the respective plurality of points on the spherical image, and to store the acquired 2D images in the storage.

Hyper-hemispherical images may be combined to generate a rectangular projection of a spherical image having an equatorial stitch line along of a line of lowest distortion in the two images. First and second circular images are received representing respective hyper-hemispherical fields of view. A video processing device may project each circular image to a respective rectangular image by mapping an outer edge of the circular image to a first edge of the rectangular image and mapping a center point of the circular image to a second edge of the first rectangular image. The rectangular images may be stitched together along the edges corresponding to the outer edge of the original circular image.

Provided is a method for playing a panoramic picture, the method comprising: acquiring a corresponding non-planar panoramic picture according to a picture acquisition instruction; acquiring picture content from the non-planar panoramic picture, and determining a main presentation axis and a presentation centre of the picture content; creating a cylindrical projection plane by using the main presentation axis and the presentation centre, wherein a cylinder extension direction of the cylindrical projection plane is substantially perpendicular to the main presentation axis, and the centre of the cylindrical projection plane essentially overlaps the presentation centre; converting the non-planar panoramic picture into a cylindrical panoramic picture with the cylindrical projection plane; and executing a playing operation on the cylindrical panoramic picture by using a planar display apparatus.

A point cloud data preprocessing method, a point cloud geometry coding method and apparatus, and a point cloud geometry decoding method and apparatus are disclosed. The preprocessing method includes: performing coordinate conversion on original point cloud data to obtain a representation of an original point cloud in a cylindrical coordinate system; unfolding the cylindrical coordinate system to obtain a two-dimensional structure; and performing regularization processing on the two-dimensional structure based on a geometric distortion measure to obtain a regularized structure. The coding method includes: performing predictive coding on preprocessed original point cloud data to obtain a geometric information bitstream.

Provided in the present invention is a panoramic image acquisition device, which comprises a body, a plurality of cameras, a image extraction processor, and an image combination processor; the cameras being provided on the body at an approximate spacing between the human eyes, for acquiring partial pictures of a plurality of different shooting angles; the image extraction processor being connected to the plurality of cameras, for acquiring, on the basis of the human eyes simulating the orientations of the cameras, left-eye pictures and right-eye pictures of the partial pictures corresponding to the cameras; the image combination processor being connected to the image extraction processor, for combining the left-eye pictures of all the partial pictures into a left-eye panoramic picture and combining the right-eye pictures of all the partial pictures into a right-eye panoramic picture.

Disclosed is an image generation apparatus generating and outputting a panoramic image that is obtained by converting, to a planar shape, a projection plane onto which a scene within at least a partial range of a virtual sphere as viewed from an observation point is projected. The panoramic image is such that a unit area on the virtual sphere containing a given attention direction as viewed from the observation point is converted to a broader area than other unit areas. The image generation apparatus generates the panoramic image corresponding to the projection plane such that a portion of a main line that links a position in the attention direction to a position in a direction opposite the attention direction and is within the panoramic image corresponding to a unit amount of an angle of rotation around the observation point is maximized in length at a position closest to the attention direction.

A system captures a first hemispherical image and a second hemispherical image, each hemispherical image including an overlap portion, the overlap portion capturing a same field of view, the two hemispherical images collectively comprising a spherical FOV and separated along a longitudinal plane. The system maps a modified first hemispherical image to a first portion of the 2D projection of a cubic image, the modified first hemispherical image including a non-overlap portion of the first hemispherical image, and maps a modified second hemispherical image to a second portion of the 2D projection of the cubic image, the modified second hemispherical image also including a non-overlap portion. The system maps the overlap portions of the first hemispherical image and the second hemispherical image to the 2D projection of the cubic image, and encodes the 2D projection of the cubic image to generate an encoded image representative of the spherical FOV.

The present application provides a method and device for constructing a projection image. The method for constructing a projection image comprises: performing projection on an equirectangular panoramic image with a cylindrical surface equal-area projection model to obtain a cylindrical surface equal-area projection image; obtaining a two-dimensional coordinate of each of pixels in the cylindrical surface equal-area projection image; obtaining a two-dimensional coordinate in the equirectangular panoramic image corresponding to each of pixels in the cylindrical surface equal-area projection image; performing pixel interpolation on the cylindrical surface equal-area projection image based on color information of each of pixels in the equirectangular panoramic image and the obtained two-dimensional coordinate in the equirectangular panoramic image corresponding to each of pixels in the cylindrical surface equal-area projection image to generate a panoramic image subjected to the cylindrical surface equal-area projection transformation. The resolution and bit rate of the panoramic image or video can be reduced by the method of the present application.

Embodiments relate to converting spatial features to a map projection. Initially, a map request that specifies the map projection for a geographic area is obtained. A spatial feature is identified for projecting into the map projection. Until a bisect threshold is satisfied for each line segment in the spatial feature, a bisect is determined for each of the line segments; each line segment is projected into the map projection; and if the bisect threshold is not satisfied for a line segment, the line segment is divided into subsegments, where the bisect threshold specifies an error distance for the line segment after projection. The modified spatial feature is projected into the map projection to obtain a projected spatial feature, and a polar coordinate system that corresponds to the map projection is used to render the projected spatial feature in a spatial map.