New publication: Full-range, high-speed 1um SD-OCT

Full-range, high-speed, high-resolution 1μm spectral-domain optical coherence tomography using BM-scan for volumetric imaging of the human posterior eye

This our paper is now available on Optics Express.

>>[Abstract and PDF]

Citation
S. Makita, T. Fabritius, and Y. Yasuno, "Full-range, high-speed, high-resolution 1μm spectral-domain optical coherence tomography using BM-scan for volumetric imaging of the human posterior eye," Opt. Express 16, 8406-8420 (2008).


Abstract
An alternative optical coherence tomography (OCT) to clinical ophthalmic 830 nm spectral-domain OCTs (SD-OCT) is demonstrated. An axial resolution of 7.4 μm, ranging depth of 4.2 mm in tissue, sensitivity of 98.5 dB, and detection speed of 38,300 axial scans/s have been achieved. These are comparable or superior to those of recently commercially available ophthalmic 830 nm SD-OCTs in clinics. In addition, fast volumetric imaging for the in vivo human posterior eye with high-contrast of the choroid is achieved. A broadband 1.04 μm light source enables the high-contrast and high resolution imaging of the retina and choroid. The ranging depth is extended by applying a full-range imaging method with an electro-optic modulator (BM-scan method). A prototype high-speed InGaAs line scan camera with 1024 pixels is used. A newly reported sensitivity improvement property of the BM-scan method demonstrates a sensitivity enhancement of 5.1 dB. We also introduce a newly developed resampling calibration method of spectrum that is independent of the intrinsic dispersion mismatch of the interferometer. The three-dimensional structure of the in vivo human optic nerve head with a very deep cupping is successfully visualized.

New publication: PS-SS-OCT

Now the paper about PS-SS-OCT with continuous source polarization modulation is available on Optics Express.


M. Yamanari, S. Makita, and Y. Yasuno, "Polarization-sensitive swept-source optical coherence tomography with continuous source polarization modulation," Opt. Express 16, 5892-5906 (2008)
http://www.opticsinfobase.org/abstract.cfm?URI=oe-16-8-5892

Abstract
We present fiber-based polarization-sensitive swept-source optical coherence tomography (SS-OCT) based on continuous source polarization modulation. The light source is a frequency swept laser centered at 1.31 μm with a scanning rate of 20 kHz. The incident polarization is modulated by a resonant electro-optic modulator at 33.3 MHz, which is one-third of the data acquisition frequency. The zeroth- and first-order harmonic components of the OCT signals with respect to the polarization modulation frequency have the polarimetric information of the sample. By algebraic and matrix calculations of the signals, this system can measure the depth-resolved Jones matrices of the sample with a single wavelength scan. The phase fluctuations of the starting trigger of wavelength scan and the polarization modulation are cancelled by monitoring the OCT phase of a calibration mirror inserted into the sample arm. We demonstrate the potential of the system by the measurement of chicken breast muscle and the volumetric measurement of an in vivo human anterior eye segment. The phase retardation image shows an additional contrast in the fibrous tissue such as the collagen fiber in the trabecular meshwork and sclera.

New publicationo: Quantitative Doppler OCT

Quantitative retinal-blood flow measurement with three-dimensional vessel geometry determination using ultrahigh-resolution Doppler optical coherence angiography

Our new paper was just published on Optics Letters.
This paper is open access and freely available on the follwoing link.

>> [Abstract and PDF]


Citation
S. Makita, T. Fabritius, and Y. Yasuno, "Quantitative retinal-blood flow measurement with three-dimensional vessel geometry determination using ultrahigh-resolution Doppler optical coherence angiography," Opt. Lett. 33, 836-838 (2008)

Abstract
Retinal blood flow quantification by retinal vessel segmentation with Doppler optical coherence angiography is presented. Vessel diameter, orientation, and position are determined in an en face vessel image and two representative cross-sectional flow images of the vessel. Absolute blood flow velocity is calculated with the help of the measured Doppler frequency shift and determined vessel angle. The volumetric flow rate is obtained with the position and the region of the vessel lumen. The volumetric blood flow rate of retinal arteries before and after a bifurcation is verified in a healthy human eye.

光計測シンポジウム

今週水曜日（２００７年６月６日）、パシフィコ横浜にて開催される光計測シンポジウムにおいてＣＯＧ安野が「前眼部用ＯＣＴによる臨床試験」と題して研究発表を行います。

現在ＣＯＧと筑波大学眼科、東京医科大学眼科で共同開発を行っている前眼部用３次元ＯＣＴを用いた臨床検査の結果報告。現在まで行った実際の患者さんを対象とした臨床検査の中から、３次元ＯＣＴならでは特徴的な症例を中心に紹介します。詳細は以下をご参考ください。

• 日時： 2007年６月６日（水） 午前１０時より
  
• 場所：パシフィコ横浜
• 公式サイト： 光計測シンポジウム

Joschi

COG オフィシャルチャットルーム

Skype Open Chat を利用した COG オフィシャルチャットルームを開設しました。このリンク をクリック、またはこのブログ右上のリンクあから Chat Room へ。技術屋/臨床屋のおしゃべりの場としてご利用ください。

注）利用にはSkypeが必要です。Skype Open Chat に関してはこのページをご覧下さい

Joschi

私（安野）もぶらぶらしているので、いたら声掛けてください。

Paper published: Line-field SD-OCT

Our paper "High-speed three-dimensional human retinal imaging by line-field spectral domain optical coherence tomography" was published in Optics Express. This paper describes a high-speed parallel spectral domain optical coherence tomography system and its optimization for in vivo retinal imaging. This system has the measurement speed of 823,200 A-lines/s for a single frame cross-sectional measurement and 51,500 A-lines/s for a three-dimensional volumetric measurement. The sensitivity was measured to be 89.4 dB with a probe power of 112 uW, and the axial resolution was measured to be 7.4 um.

This article is open access and downloadable from this page.

Joschi

COG appears at ARVO

We COG appears at ARVO conference in Fort Lauderdale, Florida, USA.We give 10 presentations including 3 paper presentations.

Search the presentations at the official site of ARVO.

See you at ARVO!

1um SS-OCT + S-OCA paper appeared in Optics Express

Our paper "In vivo high-contrast imaging of deep posterior eye by 1-um swept source optical coherence tomography and scattering optical coherence angiography" was published in Optics Express;

Y. Yasuno, Y. Hong, S. Makita, M. Yamanari, M. Akiba, M. Miura, and T. Yatagai, "In vivo high-contrast imaging of deep posterior eye by 1-um swept source optical coherence tomography and scattering optical coherence angiography," Opt. Express 15, 6121-6139 (2007).

This paper is freely downloadable from the web site of Optics Express.

(Link to Optics Exress)

People

Faculty staff

• Yoshiaki Yasuno (Assistant Professor, Group Leader)
• Shuichi Makita (Assistant Professor)

PhD candidates

• Arata Miyazawa
• Young-Joo Hong
• Kazuhiro Kurokawa
• Duan Lian

Secretary

• Chie Yoshinaga

External members

• Masahiro Miura (MD, Associate Professor from Tokyo Medical University)

About us

The computational optics group (COG) was formed in 1999 as a division of applied optics laboratory, institute of applied physics, university of Tsukuba. On that moment we were not COG but spatio-temporal optics group, and our main research subject was spatio-temporal optical computing.

In 2000, we started a optical measurement project using spatio-temporal optical computing technologies, and in 2002, we changed our direction to more computationally.

Since 2002, our main research interest is computer assisted optical measurment. We are trying to introduce computational technologies into optical measurement.

Since 2007, we are an independent research group and no longer a part of Applied Optics Laboratory of University of Tsukuba.

Contact and Access

Map

View COG office in a larger map

Access to COG Office

From Tokyo:

1. Take Tsukuba Express train to Tsukuba station.
2. Take a bus to Tsukuba-Daigaku-Chuo (Center of Tskuba University, 筑波大学中央) or Tsukuba-Daigaku-Junkan Migi-Mawari (Tsukuba University Shuttle/Right circular path, 筑波大学循環右回).
3. The closest bus-stop to our office is Daisan-Eria-Mae (3rd Area of the University, 第3エリア前). When you get off the bus, you'll see a tall brown building (Building-F of Institute of Engineering, 工学系F棟). Our office is at the 7th floor of this building, room 702. Note that the frequency of the bus is around every 10-15 min.

From Narita (New Tokyo) Airport:

1. There is a direct bus to Tsukuba bus-center (next to Tsukuba station). From Narita to Tsukuba, reservation is not required, and you can buy a bus ticket at Narita Airport. The timetable is available on this page.
2. From Tsukuba bus-center, take a bus to Tsukuba-Daigaku-Chuo (Center of Tskuba University, 筑波大学中央) or Tsukuba-Daigaku-Junkan Migi-Mawari (Tsukuba University Shuttle/Right circular path, 筑波大学循環右回).
3. The closest bus-stop to our office is Daisan-Eria-Mae (3rd Area of the University, 第3エリア前). When you get off the bus, you'll see a tall brown building (Building-F of Institute of Engineering, 工学系F棟). Our office is at the 7th floor of this building, room 702. Note that the frequency of the bus is around every 10-15 min.

From Haneda (Tokyo) Airport:

1. There is a direct bus to Tsukuba bus-center (next to Tsukuba station). From Haneda to Tsukuba, reservation is not required, and you can buy a bus ticket at Haneda Airport. The timetable is available on this page.
2. From Tsukuba bus-center, take a bus to Tsukuba-Daigaku-Chuo (Center of Tskuba University, 筑波大学中央) or Tsukuba-Daigaku-Junkan Migi-Mawari (Tsukuba University Shuttle/Right circular path, 筑波大学循環右回).
3. The closest bus-stop to our office is Daisan-Eria-Mae (3rd Area of the University, 第3エリア前). When you get off the bus, you'll see a tall brown building (Building-F of Institute of Engineering, 工学系F棟). Our office is at the 7th floor of this building, room 702. Note that the frequency of the bus is around every 10-15 min.

Contact

• Phone/Fax: +81-29-853-5217
• E-mail: cogoffice@optlab2.bk.tsukuba.ac.jp
• Institute of Applied Physics, University of Tsukuba, Tennodai 1-1-1, Tsukuba, Ibaraki, 305-8573, Japan