Field Emission Microscopic Observation of Effects of Oxygen or Air on the High Temperature Tungsten Cathode

By using Muller-type field emission microscope with an ordinary pumping system, effects of gas introduction and filed desorption on a carbon-adsorbed tungsten surface are examined at high temperatures around 1500°K. The removal of carbon from the tungsten surface is verified when a very small quantity of oxygen or air is introduced into the tube. The carbon-adsorption on the tungsten surface caused by the decomposition of vacuum oil on the tip under the conventional operating condition is observed successively during the process. From the results, it is found that the change in the 011 and the 111 regions is always regular, but in the 001 region it is very complicated. The field desorption effect on the carbon-adsorbed tungsten surface is also observed, and the same change as obtained in the gas introduction is found in the 001 region

Extraction of Disease Area from Retinal Optical Coherence Tomography Images Using Three Dimensional Regional Statistics

AbstractWe propose a new extraction method of the macular disease area in the human retinal layer from OCT images using three dimensional regional statistics. In previous researches, we extracted disease area by using the mean and standard deviation of the two dimensional disease part pointed out by a clinical doctor. However, the previous method cannot extract disease area for some disease OCT images precisely. In this paper, we propose a new extraction method of the disease area using three dimensional regional statistics. We use a set of 128 images (3D-OCT image) consisted of 2 dimensional OCT retinal image about one retina of a patient. The regional mean and regional standard deviation of gray level are calculated in the three dimensional region of interest (ROI, 125 (=5 × 5 × 5) pixels) in the abnormal area pointed by a clinical doctor. These values are compared with every ROI in the abnormal area to extract the disease area, and the proposal system measures the volume of the disease area. We apply the proposed method to OCT images of 5 patients with retinal diseases. As a result, we can measure the volume of the abnormal area with 80.7% average accuracy

Fast calculation method with saccade suppression for a computer-generated hologram based on Fresnel zone plate limitation

The computer-generated hologram (CGH) is an ideal 3D technology that can satisfy all the physiological factors of the human eye (such as binocular parallax, focus adjustment and convergence etc.) by simulating the recording part of traditional optical holography with a computer. CGH has a lot of advantages such as being able to be used for animation. However, it also has many disadvantages, and one of them is the large amount of calculation. A saccade is one of a very rapid movement of human eye, and also, it is an ability of the eye to quickly and accurately move from one target to another. This is very critical for reading and involves very precise and specific eye movements. Saccades normally happen at a frequency of 2 - 8 times per second in daily life without our being conscious, and their peak angular speed can reach 900 degrees/second. However, saccades can also be initiated by an expected stimulus such as looking from one object to another, and they last from 20 - 200 ms depending on their amplitude. In addition, our visual information is suppressed while saccade occurs. In this paper, to realize the fast calculation of CGHs, a new method is proposed that uses saccades to reduce the amount of CGH calculation without any negative effects on observers viewing CGH reconstruction images. We increased high-speed calculation by at least 4 times through Fresnel zone plate limitation and 4.64 times through saccade suppression. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreemen