日本放送协会（NHK）是日本的公共媒体机构，其英文缩写来自于日语罗马字转写“Nippon Hoso Kyokai”的首字母。 NHK是日本第一家覆盖全国的广播电台及电视台，其第一条广播节目于1925年由前身东京放送局播出。1926年，名古屋、大阪、东京三地的广播局正式整合为现在的NHK。 1948年，日本政府颁布《广播法》，确立NHK特殊的法律地位，使其成为类似英国广播公司（BBC）模式的依靠民众缴纳视听费运营而独立于商业资本外的公立媒体。 NHK现今拥有6个电视频道和3套广播节目，以面向日本国内提供播送服务。另外，NHK的国际频道面向国外提供广播和电视服务，包括18种语言的新闻网站。
Existing arbitrary-shaped text (ArT) spotting models have used coordinate-based error (CBE) loss to optimize polygon region detection. Optimization using CBE loss requires a fine-grained ground truth (FineGT), which is a fixed-length list of polygon vertices. However, not all datasets have FineGT, and creating FineGT is costly. In this paper, we propose Polygon Pixel Intersection over Union (PPIoU), which shows the similarity of polygon regions and can be used for neural network training without FineGT. Unlike CBE loss, PPIoU loss represents the region-based error for polygons and is not affected by the number of polygon vertices. PPIoU loss allows the use of multiple datasets containing polygons with different numbers of vertices, making it easy to increase the amount of training data. This is a useful feature since more training data generally improves accuracy. We show that the PPIoU loss can easily improve the accuracy of existing text spotting models.
This study presents the required horizontal FoV for ideal HMDs that bring an indistinguishable experience from the state of not wearing them. We investigated the threshold of the horizontally visible range relative to the head, when the size of the eye displacement is equivalent to that in real life. We confirmed that the required FoV was smaller than that in a previous study, in which the participants' eye displacement was at its maximum. We found that the required FoV was approximately 229° when the peripheral luminance gradually decreased, as in vignetting.
