• Journal of the Optical Society of Korea
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• 제14권4호
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• pp.388-394
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• 2010

In this paper the object recognition performance of a photon counting integral imaging system is quantitatively compared with that of a conventional gray scale imaging system. For 3D imaging of objects with a small number of photons, the elemental image set of a 3D scene is obtained using the integral imaging set up. We assume that the elemental image detection follows a Poisson distribution. Computational geometrical ray back propagation algorithm and parametric maximum likelihood estimator are applied to the photon counting elemental image set in order to reconstruct the original 3D scene. To evaluate the photon counting object recognition performance, the normalized correlation peaks between the reconstructed 3D scenes are calculated for the varied and fixed total number of photons in the reconstructed sectional image changing the total number of image channels in the integral imaging system. It is quantitatively illustrated that the recognition performance of the photon counting integral imaging system can be similar to that of a conventional gray scale imaging system as the number of image viewing channels in the photon counting integral imaging (PCII) system is increased up to the threshold point. Also, we present experiments to find the threshold point on the total number of image channels in the PCII system which can guarantee a comparable recognition performance with a gray scale imaging system. To the best of our knowledge, this is the first report on comparisons of object recognition performance with 3D photon counting & gray scale images.

• 전자공학회논문지
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• 제51권2호
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• pp.69-75
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• 2014

기존의 피플 카운팅 시스템(People Counting System)은 주로 오버헤드(Overhead) 시점에 설치된 단일 카메라를 활용하기 때문에, 겹침 및 가림 현상과 일정 크기 이상의 소지품, 급격한 조명 변화와 같은 외부 환경적 요인들로 인해 객체 인식에 장애가 발생하고, 다양한 환경에서 카운팅을 수행하기에 어려움이 존재한다. 이에 본 논문에서는 기존 단일 시점 피플 카운팅 시스템의 인식 장애 개선 및 외부 환경적 요인들에 보다 강인하게 카운팅할 수 있도록, 오버헤드 및 전면 시점에 두 개의 깊이 카메라를 활용하는 얼굴 나이 그룹별 피플 카운팅 시스템을 제안한다. 제안 시스템은 오버헤드 영상 처리, 전면 영상 처리, 동일 객체 판별, 얼굴 나이 그룹 분류, 입퇴장 카운팅의 총 5가지 처리를 통해 얼굴 나이 그룹별 피플 카운팅을 수행한다. 제안 시스템을 C++, OpenCV 및 Kinect SDK를 기반으로 구현하여, 나이 그룹별로 10명씩 총 40명을 대상으로 피플 카운팅 성능과 나이 그룹 분류 성능을 각각 평가하였다. 성능 평가 결과는 피플 카운팅에서 약 98%의 정확도를 나타냈고, 나이 그룹 분류는 약 74.23%의 정확도를 보였다.

• Journal of information and communication convergence engineering
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• 제19권4호
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• pp.276-283
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• 2021

In this paper, we propose an effective noise reduction method for photon counting imaging using a discrete wavelet transform. Conventional 2D photon counting imaging was used to visualize the object under dark conditions using statistical methods, such as the Poisson random process. The photons in the scene were estimated using a statistical method. However, photons which disturb the visualization and decrease the image quality may occur in the background where there is no object. Although median filters are used to reduce the noise, the noise in the scene remains. To remove the noise effectively, our proposed method uses the discrete wavelet transform, which removes the noise in the scene using a specific thresholding method that utilizes photon counting imaging characteristics. We conducted an optical experiment to demonstrate the denoising performance of the proposed method.

• 반도체디스플레이기술학회지
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• 제15권3호
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• pp.24-29
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• 2016

One of the main applications of digital image processing is the estimation of the number of certain types of objects (cells, seeds, peoples etc.) in an image. Difficulties of these counting problems depends on various factors including shape and size variation, degree of object clustering, contrast between object and background, object texture and its variation, and so on. In this paper, a new automatic colony counting algorithm is proposed. We focused on the two applications: counting the bacteria colonies on the agar plate and estimating the number of seeds from images captured by smartphone camera. To overcome the shape and size variations of the colonies, we adopted the distance transformation and peak detection approach. To estimate the reference size of the colony robustly, we also used k-means clustering algorithm. Experimental results show that our method works well in real world applications.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2014년도 제49차 동계학술대회논문집 22권1호
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• pp.251-252
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• 2014

본 논문에서는 차영상 기법을 이용하여 이동하는 객체를 탐지하고 계수하는 시스템을 제안한다. 제안된 시스템은 카메라를 통해 들어온 입력 영상과 배경의 차이를 통해 객체를 탐지하고 객체의 움직임을 분석하여 이동 객체를 계수한다. 실험 결과를 통해 물체의 이동 객체의 탐지 및 계수가 이루어짐을 확인 할 수 있다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1161-1166
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• 2011

A camera is mounted vertically downwards viewing the people heads from the top. This configuration is successful in people counting technique especially when only a few isolated people pass through a counting region in a non-crowded situation. Thus, this paper describes object counting which detects and count moving people using mixture of gaussian and motion vector. This method is intended to estimates the number of people in outdoor environment. This method use single gaussian background modeling which is more robust an noise and has adaptiveness. The experimental results that is based on mixture of gaussian and motion vector is also helpful to design intelligent surveillance.

• 해양환경안전학회지
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• 제23권4호
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• pp.415-420
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• 2017

본 논문에서는 머신비전을 이용하여 컨베이어 시스템에서 이동하는 객체를 계수하는 알고리즘을 제안하였다. 영상처리를 이용한 객체 계수 시스템은 유동인구나 교통량 파악 등의 다양한 산업현장에서 사용되고 있으며, 주로 템플릿 매칭이나 기계학습의 방법으로 검출하여 추적 후 계수한다. 하지만 빠르게 움직이는 컨베이어 벨트위의 물체를 검출하기 위해서는 연산에 소요되는 시간이 짧아야 하므로 영역기반의 방법으로 영상처리를 하였다. 본 연구에서는 모양과 크기, 그리고 색깔이 비슷한 전복 치패를 계수하였다. 컨베이어 시스템은 한 방향으로 동작하는 특성을 이용하여 첫 번째 영역에서 치패를 검출하여 정보를 얻은 것을 기반으로 다음 프레임에서의 물체의 위치 범위를 계속적으로 변화하여 치패를 검출하고 각각의 획득한 정보를 비교하여 계수하였다. 치패가 간격을 두고 이동 시에는 정확하게 계수됨을 확인하였으며, 치패가 붙어서 오는 경우에는 크기정보를 이용하여 계수하여 중복되거나 누락됨을 방지하였다. 본 논문에서 제안한 알고리즘은 컨베이어 시스템 위에서 움직이는 다양한 객체 계수 제어에 적용할 수 있을 것이다.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 창립 20주년기념 특별학술발표회
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• pp.165-166
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• 2009

A hologram was recorded with two-dimensional scanning of an optical fiber connected to a single-photon counting detector under ultra-weak illumination. The object image was clearly reconstructed in a computer from the hologram. The dependence of hologram quality on the illumination light intensity was estimated.

• Journal of the Optical Society of Korea
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• 제15권4호
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• pp.357-361
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• 2011

Photon-counting sensing is a widely used technique for low-light-level imaging applications. This paper proposes a distance information extraction method with photon-counting passive sensing under low-lightlevel conditions. The photo-counting passive sensing combined with integral imaging generates a photon-limited elemental image array. Maximum-likelihood estimation (MLE) is used to reconstruct the photon-limited image at certain depth levels. The distance information is extracted at the depth level that minimizes the sum of the standard deviation of the corresponding photo-events in the elemental image array. Experimental and simulation results confirm that the proposed method can extract the distance information of the object under low-light-level conditions.

• Journal of the Optical Society of Korea
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• 제20권5호
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• pp.579-585
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• 2016

Integral imaging combined with photon-counting detection has been researched for three-dimensional information sensing under low-light-level conditions. This paper addresses the extraction of distance information with photon-counting integral imaging. The longitudinal distance to the object is obtained utilizing photon-counting elemental images. The pixel disparity is estimated by maximizing the nonlinear correlation of photocounts. The first- and second-order statistical properties of the nonlinear correlation are theoretically derived. In the experiments, these properties are verified by varying the mean number of photocounts in the scene. The average distance is compared to that from the intensity information, showing the robustness of the proposed system even at low photocounts.