8K, also known as Super Hi-Vision, is a next-generation ultra-high-resolution television system created by NHK. Its video format comprises 7,680 × 4,320 pixels (16 times the total number of pixels of an HDTV). 8K features four times the number of pixels as 4K, but that does not mean to say that 8K specifications are decided based on a competition in pixel count. They are determined, rather, on human science research that aims to determine the conditions under which video can provide “high presence” that makes the viewer feel as if he or she is actually present in the scene shown. Medical Imaging Consortium (MIC) has studied endoscopic surgeries using 8K imaging technologies since 2013. It was confirmed that an 8K endoscope clearly depicts details that are difficult to see using conventional HDTV endoscopes, including thin blood vessels, nerves and the borders of body organs. Based on the fundamental research at MIC, we have developed the world’s first 8K endoscope commercial camera system.
We have started clinical application of 8K ultra-high definition (UHD; 7680 x 4320 pixels) technology to a rigid endoscopic system for advanced minimal invasive surgery. Our 8K UHD endoscopic system consists of an 8K UHD camera head with a lens adapter, rigid endoscope, xenon light source, 8K UHD monitor, and 8K UHD recorder. The first model of an 8K UHD camera head was developed based on a broadcasting camera in 2014, and the weight was 2.2 kg. The second model of an 8K UHD camera head was our original achievement in 2016, and the weight was 450 g. In 2017, we finally succeeded in developing the world’s smallest 8K UHD camera head of 370 g weight for mass production. We were able to achieve clinical success using the first model in two cases of cholecystectomy in 2014. Furthermore, after downsizing and weight saving of the 8K UHD camera head, we performed four cholecystectomies with higher maneuverability in the abdominal cavity using the second model in 2017. These experimental and clinical studies revealed the engineering and clinical feasibility of the 8K UHD endoscope. The 8K UHD endoscope promises new possibilities for intricate procedures including anastomoses of thin blood vessels and identification of thin nerves, as well as more confident surgical resections of various types of cancer tissues. We believe that our 8K UHD endoscopic imaging is very likely to lead to major changes in the future of medical practice, not only in typical endoscopic surgery but also in new heads-up surgery.
An 8K4K-LCD with the diagonal size of 55 inch has been developed. The backplane is based on an amorphous silicon (a-Si) technology and can operate at 120Hz, which is achieved by developing a technology to compensate the charging voltage of pixels. The realization of a high resolution of 8K4K and a high frame frequency of 120Hz is the world first for LCDs with a-Si backplanes. Moreover, a backlight system with laser light sources expands the color gamut. The newly developed LCD covers 99% of color space defined in BT.2020.
Additionally, we have established three dimensional 8K4K technology. A 3D polarization filter is attached on the 55-in. 8K4K LCD. The vertical viewing angle of 8K-3D LCD prototype is 8.6 degrees at its optimal viewing position set to 1.2m.
Active matrix flat panel imagers (AMFPI) have become the dominant detector technology for digital radiography and fluoroscopy. For low dose imaging, electronic noise from the amorphous silicon thin film transistor (TFT) array degrades imaging performance. We have fabricated the first prototype solid-state AMFPI using a uniform layer of avalanche amorphous selenium (a-Se) photoconductor to amplify the signal to eliminate the effect of electronic noise. We have previously developed a large area solid-state avalanche a-Se sensor structure referred to as High Gain Avalanche Rushing Photoconductor (HARP) capable of achieving gains of 75. In this work we successfully deposited this HARP structure onto a 24 x 30 cm2 TFT array with a pixel pitch of 85 μm. An electric field (ESe) up to 105 Vμm-1 was applied across the a-Se layer without breakdown. Using the HARP layer as a direct detector, an X-ray avalanche gain of 15 ± 3 was achieved at ESe = 105 Vμm-1. In indirect mode with a 150 μm thick structured CsI scintillator, an optical gain of 76 ± 5 was measured at ESe = 105 Vμm-1. Image quality at low dose increases with the avalanche gain until the electronic noise is overcome at a constant exposure level of 0.76 mR. We demonstrate the success of a solid-state HARP X-ray imager as well as the largest active area HARP sensor to date.
We have previously proposed SAPHIRE (scintillator avalanche photoconductor with high resolution emitter readout), a
novel detector concept with potentially superior spatial resolution and low-dose performance compared with existing
flat-panel imagers. The detector comprises a scintillator that is optically coupled to an amorphous selenium
photoconductor operated with avalanche gain, known as high-gain avalanche rushing photoconductor (HARP). High
resolution electron beam readout is achieved using a field emitter array (FEA). This combination of avalanche gain,
allowing for very low-dose imaging, and electron emitter readout, providing high spatial resolution, offers potentially
superior image quality compared with existing flat-panel imagers, with specific applications to fluoroscopy and breast
imaging. Through the present collaboration, a prototype HARP sensor with integrated electrostatic focusing and nano-
Spindt FEA readout technology has been fabricated. The integrated electron-optic focusing approach is more suitable for
fabricating large-area detectors. We investigate the dependence of spatial resolution on sensor structure and operating
conditions, and compare the performance of electrostatic focusing with previous technologies. Our results show a clear
dependence of spatial resolution on electrostatic focusing potential, with performance approaching that of the previous
design with external mesh-electrode. Further, temporal performance (lag) of the detector is evaluated and the results
show that the integrated electrostatic focusing design exhibits comparable or better performance compared with the
mesh-electrode design. This study represents the first technical evaluation and characterization of the SAPHIRE concept
with integrated electrostatic focusing.
Conference Committee Involvement (2)
Ultra-High-Definition Imaging Systems II
2 February 2019 | San Francisco, California, United States
Ultra-High-Definition Imaging Systems
31 January 2018 | San Francisco, California, United States