Takayuki Yamashita

We propose a phase detection autofocus (PDAF) method for three-chip 8K (UHD-2) 240-frame/sec cameras that detects the in-focus position of a lens by using disparity information between pixels with different apertures across multiple sensors. This multiplane PDAF method executes pupil division in the same incident position while using simple metal-shielded pixel technology, which can achieve accurate AF and enable low-cost implementation. The proposed method implemented in a UHD-2 three-chip camera incorporating UHD-2 sensors with half-shielded phase-detection pixels into the blue and red channels demonstrated more robust disparity calculation than the conventional single-chip metal-shielded-based PDAF method.

To provide an aspect-free television (TV) service that allows viewers to watch more attractive TV programs using various aspect ratios based on the creator’s intent, we investigate the system requirements and specific transmission methods for live production in broadcast stations. We propose the use of a 16:9 active video area in conventional video signals such as high-definition (HD)/ultrahigh-definition-1 (UHD-1) as containers and determine the range that the user-specified aspect ratio video occupies in the container using identifier ancillary data. This method is highly compatible with existing systems and conventional workflows. Scalability using multiple containers is considered in this study .

This article describes an improvement in the noise reduction performance of a column correlated multiple sampling (CMS) readout circuit using interleaved pixel source follower for high-resolution and high-framerate CMOS image sensors (CISs). In this architecture, the time-interleaved operation of the two pixel source followers reduces the restrictions imposed by the settling time of the pixel source followers and extends the time for multiple sampling. The noise analysis indicates that this method has an advantage of enhanced noise reduction not only for thermal noise but also for 1/f noise when a high-speed readout operation is required. The measurement of the noise performance of the 8K image sensor using the CMS with the interleaved pixel source follower method exhibits a low input-referred noise of 3.2 e⁻ at 8K 120 frames per second, while 4.6 e⁻ with the conventional single-source follower readout method. The measurement results match reasonably well with the analysis presented in this article, demonstrating the effectiveness of the interleaved pixel source follower method for high-resolution and high-framerate CISs.

Focusing difficulty has become a critical issue in 8K ultra-high definition television (UHDTV) production. Especially in 8K high-speed shooting, defocus blur significantly degrades a user's experience of slow-motion playback video. For this reason, incorporating a sensor-based phase detection autofocus (PDAF) system that can adjust the focus of a lens quickly into an 8K UHDTV camera has been strongly desired. Although conventional sensor-based PDAF systems have been designed for single-chip cameras capable of using optional color filters, the application of phase detection (PD) in professional broadcasting cameras with three-chip imaging has not been studied, in which incident light separates into three color components (red, green, and blue) by a separation prism. This paper presents an investigation into the PD property among the color channels using a newly prototyped 1.25-inch 8K 240-fps complementary metal-oxide-semiconductor (CMOS) image sensor with two types of horizontal PD pixels (left- and right-phase). Our experiment showed that crosstalk over angler responses of the PD sensor became larger as the wavelength of light increased, and that the crosstalk in each color component reduced the accuracy of the PD amount between a set of stereo images. Consequently, these results demonstrated that utilizing the phase-differential information from the blue component enables a high-precision sensor-based PDAF operation in three-CMOS imaging when shooting black and white objects

For the 2020 Tokyo Olympics and Paralympics, NHK is preparing 8K devices for 8K regular broadcasting. However, the equipment is in the early stages of development; therefore, it is necessary to continue improving their performance and operability. Particularly, the sizes of the cameras and lenses are larger than those for HDTV. Furthermore, handling uncompressed data is challenging because of the sheer size of the data. In this presentation, we introduce the current 8K UHDTV technologies that are closely related to photonics technology and the challenges for its development. Moreover, we describe our expectations for the research and development in the field of photonics.

The Japan Broadcasting Corp. (NHK) started the world’s first test satellite broadcasting of 8K/4K ultrahigh-definition (UHDTV), called Super Hi-Vision (SHV), on 1 August 2016. Coverage of the Rio Olympic Games and many fascinating 8K and 4K programs were broadcasted to 8K prototype receivers installed at all of NHK’s local stations in Japan. This paper introduces the SHV test broadcast system, especially the program playout and transmission system and the 8K/4K receivers. In addition, it describes the progress made so far in developing a full-featured 8K system that has a 120-Hz frame frequency.This paper introduces the SHV test broadcast system, especially the program playout and transmission system and the 8K/4K receivers.