Panoramic Image Mapping via Latitude-Based Segmentation

Solution Overview

Problem

Conventional methods for coding and storing panoramic images require high bit rates due to oversampling in high-latitude areas, leading to increased complexity in decoding and bit rate demands.

Innovation Solution

A novel panoramic image mapping method that partitions the spherical surface into three areas based on latitude and maps them onto different plane resolutions, allowing for efficient splicing into a two-dimensional plane, thereby reducing bit rate and oversampling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If equirectangular mapping is used to map spherical surface to two-dimensional plane, then panoramic image can be coded and stored using conventional methods, but oversampling phenomenon occurs in high-latitude areas leading to high bit rate requirements

Engineering Contradiction:

Improveease of coding and storingVSAvoidbit rate

Core Design Contradiction:

Ease of manufactureVSQuantity of substance

Solution Approach 1:

The spherical surface is divided into three distinct areas based on latitude ranges. Area I covers high-latitude regions (from -90° to Z1 and from Z2 to 90°), Area II covers the middle-latitude region (from Z1 to Z2), and Area III covers the remaining high-latitude region. Each area is then mapped to a separate plane with appropriately tailored resolution characteristics, allowing optimized bit rate allocation for each region rather than uniform oversampling across the entire sphere.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different resolution characteristics are applied to different latitude regions. Area I and Area III (high-latitude regions) use square plane mappings with resolution characteristics suited for polar regions, while Area II (middle-latitude region) uses rectangular plane mapping. This local adaptation of mapping quality ensures that each region receives appropriate sampling density without unnecessary oversampling in high-latitude areas.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If equirectangular mapping is used to map spherical surface to two-dimensional plane, then panoramic image can be displayed on conventional displays, but decoding complexity increases due to oversampling in high-latitude areas

Engineering Contradiction:

Improvedisplay compatibilityVSAvoiddecoding complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The spherical surface is divided into three distinct areas based on latitude ranges. Area I covers high-latitude regions (from -90° to Z1 and from Z2 to 90°), Area II covers the middle-latitude region (from Z1 to Z2), and Area III covers the remaining high-latitude region. Each area is then mapped to a separate plane with appropriately tailored resolution characteristics, allowing optimized bit rate allocation for each region rather than uniform oversampling across the entire sphere.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of mapping the entire spherical surface to a single plane with uniform sampling characteristics, the patent inverts the approach by creating multiple plane representations of different regions. The spherical surface is decomposed into Area I, Area II, and Area III, each mapped to separate planes (I′, II′, III′) with resolution characteristics optimized for their specific latitude regions, thereby reducing overall decoding complexity.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS10798301B2Panoramic image mapping method

Publication Date: 2020.10.06 PEKING UNIV SHENZHEN GRADUATE SCHOOL

AI summary

Disclosed is a panoramic image mapping method and a corresponding reversely mapping method. Particularly, the mapping process includes mapping a panoramic image or a spherical surface corresponding to Video A: first, dividing the spherical surface into three areas based on the latitudes of the spherical surface, denoted as Area I, Area II, and Area III, respectively; mapping the three areas to a square plane I′, a rectangular plane II′, and a square plane III′, respectively; then, splicing the planes I′, II′ and III′ into a plane, wherein the resulting plane is the two-dimensional image or video B. Compared with the equirectangular mapping method, the method according to the present disclosure may effectively ameliorate oversampling in high-latitude areas and effectively lower the bit rate needed by coding and the complexity of decoding. The present disclosure relates to the field of virtual reality, which may be applied to panoramic images and videos.