Publications by authors named "Wataru Takano"

6 Publications

  • Page 1 of 1

Minimizing scattering-induced phase errors in differential interference contrast microscopy.

J Biomed Opt 2020 12;25(12)

Utsunomiya University, Department of Optical Engineering, Tochigi, Japan.

Significance: Differential interference contrast (DIC) microscopes allow noninvasive in vivo observation of transparent microstructures in tissue without the use of fluorescent dyes or genetic modification. We show how to modify a DIC microscope to measure the sample phase distribution accurately and in real-time even deep inside sample tissue.

Aim: Our aim is to improve the DIC microscope's phase measurement to remove the phase bias that occurs in the presence of strong scattering.

Approach: A quarter-wave plate was added in front of the polarization camera, allowing a modified phase calculation to incorporate all four polarization orientation angles (0 deg, 45 deg, 90 deg, and 135 deg) captured simultaneously by the polarization camera, followed by deconvolution.

Results: We confirm that the proposed method reduces phase measurement error in the presence of scattering and demonstrate the method using in vivo imaging of a beating heart inside a medaka egg and the whole-body blood circulation in a young medaka fish.

Conclusions: Modifying a polarization-camera DIC microscope with a quarter-wave plate allows users to image deep inside samples without phase bias due to scattering effects.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1117/1.JBO.25.12.123703DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7734411PMC
December 2020

HVGH: Unsupervised Segmentation for High-Dimensional Time Series Using Deep Neural Compression and Statistical Generative Model.

Front Robot AI 2019 20;6:115. Epub 2019 Nov 20.

Center for Mathematical Modeling and Data Science, Osaka University, Osaka, Japan.

Humans perceive continuous high-dimensional information by dividing it into meaningful segments, such as words and units of motion. We believe that such unsupervised segmentation is also important for robots to learn topics such as language and motion. To this end, we previously proposed a hierarchical Dirichlet process-Gaussian process-hidden semi-Markov model (HDP-GP-HSMM). However, an important drawback of this model is that it cannot divide high-dimensional time-series data. Furthermore, low-dimensional features must be extracted in advance. Segmentation largely depends on the design of features, and it is difficult to design effective features, especially in the case of high-dimensional data. To overcome this problem, this study proposes a hierarchical Dirichlet process-variational autoencoder-Gaussian process-hidden semi-Markov model (HVGH). The parameters of the proposed HVGH are estimated through a mutual learning loop of the variational autoencoder and our previously proposed HDP-GP-HSMM. Hence, HVGH can extract features from high-dimensional time-series data while simultaneously dividing it into segments in an unsupervised manner. In an experiment, we used various motion-capture data to demonstrate that our proposed model estimates the correct number of classes and more accurate segments than baseline methods. Moreover, we show that the proposed method can learn latent space suitable for segmentation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/frobt.2019.00115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7805757PMC
November 2019

Erratum: Video-rate quantitative phase analysis by a DIC microscope using a polarization camera: errata.

Biomed Opt Express 2019 06 23;10(6):2967-2968. Epub 2019 May 23.

Department of Optical Engineering, Utsunomiya University, 7-1-2 Yoto, Utsunomiya, Tochigi, Japan.

[This corrects the article on p. 1273 in vol. 10, PMID: 30891345.].
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/BOE.10.002967DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6583344PMC
June 2019

Video-rate quantitative phase analysis by a DIC microscope using a polarization camera.

Biomed Opt Express 2019 Mar 19;10(3):1273-1281. Epub 2019 Feb 19.

Department of Optical Engineering, Utsunomiya University, 7-1-2 Yoto, Utsunomiya, Tochigi, Japan.

This paper describes how to take advantage of the replacement of an intensity camera with a polarization camera in a standard differential interference contrast (DIC) microscope. Using a polarization camera enables snapshot quantitative phase analysis so that real-time imaging of living transparent tissues become possible. Using our method, we quantify the phase measurement accuracy using a phantom consisting of glass beads embedded in lacquer. In order to demonstrate these advantages, we image the pumping heart and blood flow in a living egg.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/BOE.10.001273DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6420286PMC
March 2019

Generating action descriptions from statistically integrated representations of human motions and sentences.

Neural Netw 2016 Aug 16;80:1-8. Epub 2016 Mar 16.

Mechano-Informatics, University of Tokyo, 7-3-1 Hongo, Bunkyoku, Tokyo, 113-8656, Japan. Electronic address:

It is desirable for robots to be able to linguistically understand human actions during human-robot interactions. Previous research has developed frameworks for encoding human full body motion into model parameters and for classifying motion into specific categories. For full understanding, the motion categories need to be connected to the natural language such that the robots can interpret human motions as linguistic expressions. This paper proposes a novel framework for integrating observation of human motion with that of natural language. This framework consists of two models; the first model statistically learns the relations between motions and their relevant words, and the second statistically learns sentence structures as word n-grams. Integration of these two models allows robots to generate sentences from human motions by searching for words relevant to the motion using the first model and then arranging these words in appropriate order using the second model. This allows making sentences that are the most likely to be generated from the motion. The proposed framework was tested on human full body motion measured by an optical motion capture system. In this, descriptive sentences were manually attached to the motions, and the validity of the system was demonstrated.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.neunet.2016.03.001DOI Listing
August 2016

Regulation of muscular glutamate metabolism by high-protein diet in broiler chicks.

Anim Sci J 2011 Feb 13;82(1):86-92. Epub 2010 Oct 13.

Graduate School of Science and Technology, Niigata University, Niigata, Japan.

The major taste active component, glutamate (Glu), improves the taste of meat. In this study, we investigated the effect of a short-term high-protein (HCP) diet on the intramuscular free Glu content to improve the taste of meat. Furthermore, we elucidated how the muscle free Glu content was controlled by the HCP diet. Chicks (14 days old) were fed the control diet or HCP diet for 10 days. Plasma and muscle free amino acid concentrations, and activity and messenger RNA (mRNA) expression of muscle enzymes related to Glu metabolism were determined. Muscle free Glu content was increased (P < 0.01) by 51%. Activity and mRNA expression of glutaminase (GA), which is one of the major Glu-related enzymes, were significantly decreased (P < 0.05) in the HCP group because of feedback inhibition. The mRNA expression of lysine α-ketoglutarate reductase (LKR), which is the enzyme involved in lysine (Lys) degradation and Glu production, was significantly increased (P < 0.001) in the HCP group. These results suggest that short-term dietary HCP feeding is an effective treatment for improving the taste of meat. Furthermore, our results suggest that the free Glu content in muscle is regulated by GA and LKR.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/j.1740-0929.2010.00811.xDOI Listing
February 2011