• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.12
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• pp.2547-2554
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• 2009

In this paper, we proposed a face detection algorithm and a hardware implementation method for ROI(Region Of Interest) of AF(Auto Focusing). We used face features in skin regions of YCbCr color space for face detection. The face features are the number of skin pixels in face regions, edge pixels in eye regions, and shadow pixels in lip regions. The each feature was statistically selected by 2,000 sample pictures of face. The proposed algorithm detects two faces that are closer center of the image for considering the effectiveness of hardware resource. The detected faces are displayed by rectangle for ROI of AF, and the rectangles are represented by positions in the image about starting point and ending point of the rectangles. The proposed face detection method was verified by using FPGA boards and mobile phone camera sensor.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.1
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• pp.15-22
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• 2005

In this paper, we propose a face recognition system by using the CCD color image. We first get the face candidate image by using YCbCr color model and adaptive skin color information. And we use it initial curve of active contour model to extract face region. We use the Eye map and mouth map using color information for extracting facial feature from the face image. To obtain center point of Log-polar image, we use extracted facial feature from the face image. In order to obtain feature vectors, we use extracted coefficients from DCT and wavelet transform. To show the validity of the proposed method, we performed a face recognition using neural network with BP learning algorithm. Experimental results show that the proposed method is robuster with higher recogntion rate than the conventional method for the rotation and scale variant.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.607-610
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• 2005

상황에 따라 조명의 밝기나 종류 등에 영향으로 CMOS 이미지 카메라 센서로부터 입력 받은 영상의 색상은 원색과 차이가 있다. 이러한 왜곡된 색상을 Red, Green, Blue와 휘도를 이용하여 원래의 색으로 표현하는 과정이 White Balance이다. 사람은 색이 눈으로 입사되는 물리적인 자극 외에 대뇌의 작용으로 광원이 바뀌어도 같은 색으로 인지하는 특징이 있다. 따라서 이러한 과정이 없을 시에는 우리의 눈으로 보는 것과 영상장치를 통해서 모니터에 표시되는 영상의 색상과 차이가 생긴다. 본 논문에서는 RGB와 휘도를 이용하는 방법과 논문에서 제안한 히스토그램을 이용하는 방법에 대해 소프트웨어를 사용하여 각각의 상황에 따라 알고리즘을 적용하여 WB를 수행한 결과에 대하여 PSNR을 구하여 비교 분석한 후 최적화된 알고리즘을 이용하여 하드웨어 설계 언어인 VHDL을 사용하여 구현하고, ModelSim6.0a를 이용하여 데이터를 검증한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.94-97
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• 2009

본 논문에서는 실제 도로 환경에서의 실시간 차선 인식 방법을 제안한다. 전방주시카메라를 활용하여 촬영한 입력영상으로부터 도로영역에 해당하는 관심영역을 추출하고 반복적인 평균 명도를 측정하여 이진화함으로써 차선 특징을 검출하고 YCbCr 변환한 영상에 대한 실험 임계값을 적용하여 중앙선의 특징을 검출하였다. 이에 Canny 알고리즘을 이용한 에지 추출로 허프 변환시의 작업량을 최소화하였으며 허프 변환하여 얻은 차선 후보군으로부터 각도를 기반으로 필터링하여 통계적으로 우선순위가 높은 선분을 차선으로 인식하였다. 또한 실제 도로 환경에서 수집한 동영상으로 실험한 결과 강건한 차선 인식률을 보였다.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.861-864
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• 2000

본 논문에서는 물체의 고유 칼라 정보 복원을 통하여 조명의 영향을 받지 않는 칼라 기반 얼굴검출 기법을 제안한다. 즉 주위 조명 영향으로부터 RGB 성분 계수를 파악하여 조명 성분에 영향을 받은 성분을 상쇄시키고, 색포화도와 밝기값 보상을 통해 고유 칼라를 복원(color recover)하는 실험을 하였고, 복원된 영상을 YCbCr 좌표계로 변환시킨 후, CbCr 각각에 대해 살색 성분이 나타내는 일정한 범위내의 부분을 검출하였다. 또한 이 진화 과정에서 생긴 잡음들을 형태학적인 모폴로지 필터를 통해 제거하였으며, 살색 후보 영역 중 같은 영역들은 레이블링하여 얼굴 후보 영역을 생성하였다. 그러나 칼라 정보만으로는 검출된 영역이 얼굴인지를 판단하기가 매우 어렵다. 그러므로 본 연구에서는 인간시각에 기반한 Gabor 필터를 사용하여, 검출된 살색 영역이 최종적으로 얼굴인지를 판별하는 효율적인 알고리즘을 제안한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.67-69
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• 2010

대부분의 디지털 카메라는 컬러 필터 배열(Color Filter Array)을 가진 하나의 영상 획득 센서를 사용한다. 따라서 영상획득 이후에 컬러 보간 알고리즘이 필수적으로 진행된다. 또 영상 획득 과정에서 센서의 열화나 암전류 등과 같은 잡음이 발생하여 영상 잡음 제거 알고리즘이 필요하다. 하지만 기존의 대부분의 영상 잡음 제거 알고리즘은 컬러 필터 배열 영상의 특징인 모자이크 데이터 기반이 아닌 컬러 보간 이후의 풀 컬러영상에(YCbCr) 적용되고 있다. 따라서 잡음이 포함된 영상으로 컬러 보간을 할 경우 잡음의 공간적 상관관계(spatial correlation)가 커짐에 의한 잡음 번짐 때문에 컬러 보간 이후의 잡음제거는 더욱 어렵게 된다. 이와 같은 문제를 해결하기 위해 컬러 필터 배열 영상에 대한 잡음제거 알고리즘이 연구되고 있으며, 본 논문에서도 CMOS/CCD의 이미지 센서에서 획득된 베이어 컬러 필터 배열 영상에서 잡음을 제거하는 알고리즘을 제안한다. 이를 위해서 베이어 컬러 필터 배열 영상 데이터에서 경계(edge)의 방향성을 고려한 LMMSE 방법을 기반으로 한 잡음제거 알고리즘을 제안한다. 제안하는 알고리즘은 영상의 경계를 보존해주며 잡음제거 과정 다음에 진행되는 컬러 보간 과정에서의 잡음 번짐의 문제를 해결할 수 있다. 실험 결과를 통해 향상된 잡음 제거 효과를 확인하였다.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.6
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• pp.81-89
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• 2004

In this paper, we compare face recognition rate by PCA algorithm using distance change and embedded data being input left side and right side image in stereo images. The proposed method detects face region from RGB color space to YCbCr color space. Also, The extracted face image's scale up/down according to distance change and extracts more robust face region. The proposed method through an experiment could establish standard distance (100cm) in distance about 30∼200cm, and get 99.05% (100cm) as an average recognition result by scale change. The definition of super state is specification region in normalized size (92${\times}$112), and the embedded data extracts the inner factor of defined super state, achieved face recognition through PCA algorithm. The orignal images can receive specification data in limited image's size (92${\times}$112) because embedded data to do learning not that do all learning, in image of 92${\times}$112 size averagely 99.05%, shows face recognition rate of test 1 99.05%, test 2 98.93%, test 3 98.54%, test 4 97.85%. Therefore, the proposed method through an experiment showed that if apply distance change rate could get high recognition rate, and the processing speed improved as well as reduce face information.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.1
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• pp.1-10
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• 2008

Coloriztion algorithms, which hide color information into gray images and find them to recover color images, have been developed recently. In these methods, it is important to minimize the loss of original information while the color components are embedded and extracted. In this paper, we propose a colorization method using a wavelet packet transform in order to embed color components with minimum loss of original information. In addition, the compensation processing of color saturation in the recovered color images is achieved. In the color-to-gray process, an input RGB image is converted into Y, Cb, and Cr images, and a wavelet packet transform is applied to the Y image. After analyzing the amounts of total energy for each sub-band, color components are embedded into two sub-bands including minimum amount of energy on the Y image. This makes it possible not only to hide color components in the Y image, but to recover the Y image with minimum loss of original information. In the gray-to-color process, the color saturation of the recovered color images is decreased by printing and scanning process. To increase color saturation, the characteristic curve between printer and scanner, which can estimate the change of pixel values before and after printing and scanning process, is used to compensate the pixel values of printed and scanned gray images. In addition, the scaling method of the Cb and Cr components is applied to the gray-to-color process. Through the experiments, it is shown that the proposed method improves both boundary details and color saturation in the recovered color images.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.3 s.309
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• pp.30-38
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• 2006

In this paper, we improved to drops recognition rate according to distance using distance and depth information with 3D from stereo face images. A monocular face image has problem to drops recognition rate by uncertainty information such as distance of an object, size, moving, rotation, and depth. Also, if image information was not acquired such as rotation, illumination, and pose change for recognition, it has a very many fault. So, we wish to solve such problem. Proposed method consists of an eyes detection algorithm, analysis a pose of face, md principal component analysis (PCA). We also convert the YCbCr space from the RGB for detect with fast face in a limited region. We create multi-layered relative intensity map in face candidate region and decide whether it is face from facial geometry. It can acquire the depth information of distance, eyes, and mouth in stereo face images. Proposed method detects face according to scale, moving, and rotation by using distance and depth. We train by using PCA the detected left face and estimated direction difference. Simulation results with face recognition rate of 95.83% (100cm) in the front and 98.3% with the pose change were obtained successfully. Therefore, proposed method can be used to obtain high recognition rate with an appropriate scaling and pose change according to the distance.

• Journal of Korea Multimedia Society
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• v.15 no.10
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• pp.1196-1204
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• 2012

In this paper, a series of algorithms are proposed for controlling different kinds of multimedia contents and realizing interact between human and computer by using single input device. Human gesture recognition based on NUI is presented firstly in my paper. Since the image information we get it from camera is not sensitive for further processing, we transform it to YCbCr color space, and then morphological processing algorithm is used to delete unuseful noise. Boundary Energy and depth information is extracted for hand detection. After we receive the image of hand detection, PCA algorithm is used to recognize hand posture, difference image and moment method are used to detect hand centroid and extract trajectory of hand movement. 8 direction codes are defined for quantifying gesture trajectory, so the symbol value will be affirmed. Furthermore, HMM algorithm is used for hand gesture recognition based on the symbol value. According to series of methods we presented, we can control multimedia contents by using human gesture recognition. Through large numbers of experiments, the algorithms we presented have satisfying performance, hand detection rate is up to 94.25%, gesture recognition rate exceed 92.6%, hand posture recognition rate can achieve 85.86%, and face detection rate is up to 89.58%. According to these experiment results, we can control many kinds of multimedia contents on computer effectively, such as video player, MP3, e-book and so on.