Image Reconstruction and Optimization Using a Terahertz Scanned Imaging System

Date

2014-09-23

Author

Yildirim, Ihsan Ozan
ÖZKAN, VEDAT ALİ
Idikut, Firat
Takan, Taylan
ŞAHİN, ASAF BEHZAT
Altan, Hakan

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

215
views

0
downloads

Due to the limited number of array detection architectures in the millimeter wave to terahertz region of the electromagnetic spectrum, imaging schemes with scan architectures are typically employed. In these con fi gurations the interplay between the frequencies used to illuminate the scene and the optics used play an important role in the quality of the formed image. Using a multiplied Schottky-diode based terahertz transceiver operating at 340 GHz, in a stand-o ff detection scheme; the e ff ect of image quality of a metal target was assessed based on the scanning speed of the galvanometer mirrors as well as the optical system that was constructed. Background e ff ects such as leakage on the receiver were minimized by conditioning the signal at the output of the transceiver. Then, the image of the target was simulated based on known parameters of the optical system and the measured images were compared to the simulation. By using an image quality index based on chi(2) algorithm the simulated and measured images were found to be in good agreement with a value of chi(2) = 0.14. The measurements as shown here will aid in the future development of larger stand-o ff imaging systems that work in the terahertz frequency range.

Subject Keywords

Terahertz, Mirror galvanometer system, Scanned imaging system

URI

https://hdl.handle.net/11511/40911

DOI

https://doi.org/10.1117/12.2064827

Collections

Department of Physics, Conference / Seminar

Suggestions

OpenMETU
Core

OBJECT RECOGNITION AND LOCALIZATION WITH ULTRASONIC-SCANNING KIRAGI, H; Ersak, Aydın (1994-04-14) In this paper an object recognition and localization system based on ultrasonic range imaging to be used in optically opaque environments is introduced. The system is especially designed for robotics applications. The ultrasonic image is acquired by scanning ultrasonic transducers in two dimensions above the area where objects are located. The features that are used for recognition and localization processes are extracted from the outermost boundaries of the objects present in the input scene. Experimental ...
Compressive sensing imaging at Sub-THz frequency in transmission mode Özkan, Vedat Ali; Menteşe, Yıldız; Takan, Taylan; Şahin, Asaf Behzat; Altan, Hakan (Springer, Dordrecht, 2017-01-01) Due to lack of widespread array imaging techniques in the THz range, point detector applications coupled with spatial modulation schemes are being investigated using compressive sensing (CS) techniques. CS algorithms coupled with innovative spatial modulation schemes which allow the control of pixels on the image plane from which the light is focused onto single pixel THz detector has been shown to rapidly generate images of objects. Using a CS algorithm, the image of an object can be reconstructed rapidly....
Terahertz (>0.3THz) active imaging systems İdikut, Fırat; Altan, Hakan; Department of Physics (2016) Imaging systems based on terahertz waves are becoming an integral part of commercial and military screening applications. In this thesis, the prototype of active scan THz imaging system was constructed for detection of concealed objects at standoff distance longer than 5m. The system was mounted on a platform that can adjust in height, tilt and azimuthal angle. The methods of generation and detection of THz signal are based on Schottky diode rectifiers and Schottky diode mixers. The wavelength of the contin...
Image restoration for sparse aperture optical systems Iskender, Berk; Öktem, Sevinç Figen (2018-07-05) Sparse aperture imaging systems offer high spatial resolution while keeping the total light collection area smaller compared to their fully filled (monolithic) versions. Such systems are of interest in remote sensing and medicine applications where the size, weight, and cost of the imaging system are important. However, these systems often suffer from low image quality resulting from the non-filled sparse aperture structure. In this work, total-variation based image restoration is used to improve the image ...
Image reconstruction based on active scan techniques in the terahertz frequency range Özkan, Vedat Ali; Altan, Hakan; Özdemir, Özgür; Department of Physics (2014) THz continuous wave (CW) imaging systems have attracted interest in the past decade since they have the ability to detect non-metal threats such as ceramic knives. Moreover due to low energy levels of THz signals, these systems are not harmful. Although various types of imaging systems have been developed, the nature of THz waves has prevented the scienti c community from producing a fast, high resolution and cost e ective imaging system. In this study we have investigated both experimentally and theoretica...

Citation Formats

I. O. Yildirim, V. A. ÖZKAN, F. Idikut, T. Takan, A. B. ŞAHİN, and H. Altan, “Image Reconstruction and Optimization Using a Terahertz Scanned Imaging System,” 2014, vol. 9250, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/40911.