• ETRI Journal
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• v.26 no.1
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• pp.1-6
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• 2004

The photonic quantum ring (PQR) laser is a three dimensional whispering gallery (WG) mode laser and has anomalous quantum wire properties, such as microampere to nanoampere range threshold currents and ${\sqrt{T}}$-dependent thermal red shifts. We observed uniform bottom emissions from a 1-kb smart pixel chip of a $32{\times}32$ InGaAs PQR laser array flip-chip bonded to a 0.35 ${\mu}m$ CMOS-based PQR laser driver. The PQR-CMOS smart pixel array, now operating at 30 MHz, will be improved to the GHz frequency range through device and circuit optimization.

• Current Optics and Photonics
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• v.7 no.5
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• pp.485-495
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• 2023

The pixel size in high-resolution complementary metal-oxide-semiconductor (CMOS) image sensors continues to shrink due to chip size limitations. However, the pixel pitch's miniaturization causes deterioration of optical performance. As one solution, a quad color filter (CF) array with pixel binning has been developed to enhance sensitivity. For high sensitivity, the microlens structure also needs to be optimized as the CF arrays change. In this paper, the covered microlens, which consist of four microlenses covered by one large microlens, are proposed for the quad CF array in the backside illumination pixel structure. To evaluate the optical performance, the suggested microlens structure was simulated from 0.5 ㎛ to 1.0 ㎛ pixels at the center and edge of the sensors. Moreover, all pixel structures were compared with and without in-pixel deep trench isolation (DTI), which works to distribute incident light uniformly into each photodiode. The suggested structure was evaluated with an optical simulation using the finite-difference time-domain method for numerical analysis of the optical characteristics. Compared to the conventional microlens, the suggested microlens show 29.1% and 33.9% maximum enhancement of sensitivity at the center and edge of the sensor, respectively. Therefore, the covered microlens demonstrated the highly sensitive image sensor with a quad CF array.

• Journal of information and communication convergence engineering
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• v.15 no.4
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• pp.256-261
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• 2017

In this paper, we propose a modified smart pixel mapping (SPM) to visualize occluded three-dimensional (3D) objects in real image fields. In integral imaging, orthoscopic real 3D images cannot be displayed because of lenslets and the converging light field from elemental images. Thus, pseudoscopic-to-orthoscopic conversion which rotates each elemental image by 180 degree, has been proposed so that the orthoscopic virtual 3D image can be displayed. However, the orthoscopic real 3D image cannot be displayed. Hence, a conventional SPM that recaptures elemental images for the orthoscopic real 3D image using virtual pinhole array has been reported. However, it has a critical limitation in that the number of pixels for each elemental image is equal to the number of elemental images. Therefore, in this paper, we propose a modified SPM that can solve this critical limitation in a conventional SPM and can also visualize the occluded objects efficiently.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.249-252
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• 2003

This paper propose an advanced circuit for fingerprint sensor signal processing. We increased the voltage between ridge and valley by modifying the parasitic capacitance eliminating circuit of sensor plate. The analog to comparator was designed for comparing the sensor signal voltage with the reference signal voltage. We also propose an exective isolation strategy for removing noise and signal coupling of each sensor pixel. The 128$\times$144 pixel fingerprint sensor circuit was designed and simulated, and the layout was performed.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.1
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• pp.38-45
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• 2010

A new readout circuit involving a pixel-level reset control was studied for 2-D long wavelength infrared focal plane arrays. The integration time of each pixel can be optimized individually and automatically. Hence, the readout circuit has a wide dynamic range and good signal-to-noise ratio characteristics. The readout circuit was fabricated with a $0.35{\mu}m$ 2-poly 4-metal CMOS process for a $128{\times}128$ long wavelength infrared HgCdTe array with a pixel size of $50{\mu}m{\times}50{\mu}m$. The smart reset control with two-step background suppression improves the signal-to-noise ratio to 87dB and the dynamic range to 95.8dB.

• Journal of the Optical Society of Korea
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• v.13 no.1
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• pp.139-145
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• 2009

Computational integral imaging (CII) is a new method for 3D imaging and visualization. However, it suffers from seriously poor image quality of the reconstructed image as the reconstructed image plane increases. In this paper, to overcome this problem, we propose a CII method based on a smart pixel mapping (SPM) technique for partially occluded 3D object recognition, in which the object to be recognized is located at far distance from the lenslet array. In the SPM-based CII, the use of SPM moves a far 3D object toward the near lenslet array and then improves the image quality of the reconstructed image. To show the usefulness of the proposed method, we carry out some experiments for occluded objects and present the experimental results.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.36-38
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• 2000

An optoelectronic database filter chip for high performance database computers and applications is proposed. The proposed device is designed to perform the selection and projection operations of relational database operation on-the-fly in page-parallel manner to increase the overall performance of a database system. The device utilizes CMOS smart pixel array consists of detector and combinational logic circuit to perform the selection and projection operation.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.847-850
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• 2003

An Eye Ball Sensor (EBS) is a system that locates the point where the user gazes on. The conventional EBS using a CCD camera needs many peripherals, software computation causing high cost and power consumption. This paper proposes a compact EBS using smart CMOS Image Sensor (CIS) pixels. The proposed single chip EBS does not need any peripheral and operates at higher speed and lower cost than the conventional EBS. The test chip was designed and fabricated for 32$\times$32 smart CIS pixel array with a 0.35 um CMOS process occupying 5.3$\textrm{mm}^2$ silicon area.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.5
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• pp.324-329
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• 2015

A decreased number of readout method is investigated to provide precise pixel information for small-animal positron emission tomography (PET). Small-animal PET consists of eight modules, and each module is composed of a $6{\times}6$ array of $2{\times}2{\times}20mm^3$ lutetium yttrium orthosilicate (LYSO) crystals optically coupled to a $4{\times}4$ array of $3{\times}3mm^2$ silicon photomultipliers (SiPMs). The number of readout channels is reduced by one-quarter that of the conventional method by applying a simplified row and column matrix algorithm. The performance of the PET system and detector module was evaluated with Geant4 Application for Emission Tomography (GATE) 6.1 and DETECT2000 simulations. In the results, all pixels of the $6{\times}6$ LYSO array were decoded well, and the spatial resolution and sensitivity, respectively, of the PET system were 1.75 mm and 4.6% (@ center of field of view, energy window: 350-650 keV).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.3 no.1
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• pp.84-95
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• 2009

The ubiquitous smart home is the home of the future, which exploits context information from both the human and the home environment, providing an automatic home service for the human. Human location and motion are the most important contexts in the ubiquitous smart home. In this paper, we present a real-time human tracker that predicts human location and motion for the ubiquitous smart home. The system uses four network cameras for real-time human tracking. This paper explains the architecture of the real-time human tracker, and proposes an algorithm for predicting human location and motion. To detect human location, three kinds of images are used: $IMAGE_1$ - empty room image, $IMAGE_2$ - image of furniture and home appliances, $IMAGE_3$ - image of $IMAGE_2$ and the human. The real-time human tracker decides which specific furniture or home appliance the human is associated with, via analysis of three images, and predicts human motion using a support vector machine (SVM). The performance experiment of the human's location, which uses three images, lasted an average of 0.037 seconds. The SVM feature of human motion recognition is decided from the pixel number by the array line of the moving object. We evaluated each motion 1,000 times. The average accuracy of all types of motion was 86.5%.