Search results

Shadows, the common phenomena in most outdoor scenes, bring many problems in practical image processing. Shadow detection and removal, especial in uncalibrated outdoor image, is still a difficult problem. The purpose of this paper is to detect and to remove shadows in single outdoor image based on retinex theory.

The shadow extraction algorithm originates from a simple idea that the human‐vision‐based retinex has the natural ability to enhance the shadow regions of an image no matter it is penumbrae or umbrae. Shadows are detected by comparing the retinex‐enhanced images with original images in the paper. The shadow removal algorithm in the paper deals with the shadow regions and non‐shadow regions in the images separately using the retinex enhancement algorithm. Through adding smooth light forcibly to shadow edges and introducing shadow edge masks, the authors reduce the effects of shadow edges in shadow removal processing.

Some real single outdoor images with the umbra regions and those with penumbra regions are both experimented in the paper. Experimental results validate the feasibility of the approach.

The approach proposed here does not use any special prior knowledge and assumptions. The feasibility of this method is testified for detecting and removing both penumbrae and umbrae in the outdoor images.

To examine “universal service” as a policy objective in post‐WTO accession Chinese telecommunications and analyze the challenges of the Chinese telecommunications system in defining and promoting public service ethos in a country that is marked by staggering disparities.

A range of media, academic, industry, and policy discourses on “universal service” and a broader notion of “public service,” together with recent government efforts in promoting “universal service,” are examined and assessed to develop an analysis of the uneven nature of China's telecommunications development and reveal the dynamics of “universal service” policy formation, as well as the impetuses and impediments in developing any notion of public service telecommunications in China.

Public service issues in China need to be situated within a continuing process of uneven development which comprises dimensions other than residential telephone access. Although the ultimate policy goal appears to develop a nationally accessible telecommunications infrastructure as the basis of a unified national economy, this overall objective is beset by conflicts and contingent on the dynamics of elite and popular struggles over and beyond telecommunications development. Despite the spectacular expansion in telephone access, pragmatic concessions to dominant power groups, rather than a principled commitment to “universal service,” let alone efforts to define the social functions of telecommunications in more democratic ways, have shaped the development of China's telecommunications.

The development of China's telecommunications infrastructure offers lessons both as to the likelihood of successfully establishing an integrated national economy, and the role of public service in that context. However, the Chinese telecommunications policy field remains extremely fluid.