• International Journal of Advanced Culture Technology
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• 제3권2호
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• pp.161-170
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• 2015

Mean separated histogram equalization in order to preserve the original mean brightness has been proposed. To provide the minimum mean brightness error after the histogram modification, the input image's histogram is successively divided by the factor of 2 until the mean brightness error is satisfied the defined threshold. Then each divided group or sub-histogram will be independently equalized based on the proportional input mean. To provide the overall minimum mean brightness error, each group will be controlled by adding some certain pixels from the adjacent grey level of the next group for giving its mean near by the corresponding the divided mean. However, it still exists some little error which will be put into the next adjacent group. By successive dividing the original histogram, we found that the absolute mean brightness error is gradually decreased when the number of group is increased. Therefore, the error threshold is assigned in order to automatically dividing the original histogram for obtaining the desired absolute mean brightness error (AMBE). This process will be applied to the color image by treating each color independently.

• 인터넷정보학회논문지
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• 제13권3호
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• pp.61-73
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• 2012

본 논문에서는 영상의 밝기 평균과 분산을 이용하여 영상의 엔트로피를 최대화하는 히스토그램 명세화 기반의 영상 향상 기법을 제안한다. 제안 방법은 히스토그램 명세화 과정에서 입력 히스토그램과 목적 히스토그램 모두를 가우시안 분포로 모델링한다. 이 과정에서 입력 가우시안 분포의 평균과 분산은 입력영상의 밝기 평균값과 분산을 각각 그대로 사용한다. 목적 가우시안 분포의 평균도 입력영상의 밝기 평균값을 사용하지만, 분산은 출력 영상의 엔트로피가 최대화되는 분산을 결정하여 사용한다. 다양한 영상에 대한 실험 결과에 의하면, 기존 방법들에 비해 제안 방법은 영상의 평균 밝기를 잘 유지하면서 자연스러운 개선 결과를 보여준다.

• 방송공학회논문지
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• 제19권4호
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• pp.453-467
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• 2014

일반적인 히스토그램 평활화는 화질향상을 위한 명암대비 향상 효과가 뛰어나다. 하지만 과도한 밝기 값의 변화가 나타나기 때문에 영상의 평균밝기가 프레임 단위로 변화하는 TV와 같은 동영상 응용분야에 적용하기에는 부적합하다. 이러한 단점을 해결하기 위하여 히스토그램 평활화의 변형된 방법에 대한 다양한 연구가 이루어져 왔다. 그러나 기존의 방법들은 과포화현상(over-enhancement), 계조 현상(false-contouring)과 같은 화질 열화를 보인다. 본 논문에서는 차별적 히스토그램 압축방법을 기반으로 하는 목표 평균 밝기값을 이용한 분할 히스토그램 평활화를 통해서 개선된 명암대비 향상 기법을 제안한다. 제안한 방법은 평균 밝기값을 기준으로 히스토그램을 분할하고, 각 영역에 대해 히스토그램을 빈도수에 따라 차별적으로 압축한다. 그리고 변형된 히스토그램을 목표 평균 밝기값 기준으로 평활화한다. 이를 통하여 화질 열화를 억제하고, 동영상의 각 프레임의 평균밝기 변화를 유지하면서 명암대비를 개선시킨다. 실험 결과 제안방법은 기존 방법에 비해 동영상에서 각 프레임의 평균밝기를 잘 유지하고, 화질 열화 없이 좋은 명암대비 향상 효과를 보였다.

• 반도체디스플레이기술학회지
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• 제8권4호
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• pp.95-100
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• 2009

This paper presents an efficient disparity matching, using sum of absolute difference (SAD) and dynamic programming (DP) algorithm. This algorithm makes use of one of area-based algorithm which is the absolute sum of the pixel difference corresponding to the window size. We use the information of the right eye brightness (B) and the left eye brightness to get an best matching results and apply the results to the left eye image using the window go by the brightness of the right eye image. This is that we can control the brightness. The major feature of this algorithm called SAD+DP+B is that although Root Mean Square (RMS) performance is slightly less than SAD+DP, due to comparing original image, its visual performance is increased drastically for matching the disparity map on account of its matching compared to SAD+DP. The simulation results demonstrate that the visual performance can be increased and the RMS is competitive with or slightly higher than SAD+DP.

• 전자공학회논문지 IE
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• 제46권3호
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• pp.12-18
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• 2009

본 논문은 LED 디스플레이 시스템에서 균일하고 부드러운 영상표출을 위하여 각각의 Red, Green, Blue LED의 휘도를 조절하여 흰색보정을 유지할 수 있는 프로세서를 설계하였다. 이 프로세서는 일반적인 LED소자의 특성곡선을 근거로 "a"를 고유특성 값, "b"를 사용시간에 따른 휘도보정 값, "X"를 구동전류 값, "Y"를 휘도 값이라 할 때, "Y=aX+b"로 설정되는 휘도 특성함수에 의하여 각 픽셀의 휘도에 따른 구동 전류 값을 산출하여 휘도를 보정하고, 또한 장시간 사용 시 LED소자의 휘도 저하 문제를 해결하기 위하여 "b"값을 조절하여 LED 디스플레이 시스템의 전체 평균 휘도 값을 상향시킬 수 있도록 구현하였다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1999년도 KOBA 방송기술 워크샵 KOBA Broadcasting Technology Workshop
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• pp.29-34
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• 1999

We present a practical method for removing biotches and restoring their mission data. To detect blotches, we employ a robust approach of local analysis of spatiotemporal anisotropic brightness continuity Our approach uses first-order spatiotemporal directional derivatives to select the smoothest direction for each examined pixel, and puts out the incorruption probability that he examined pixel may not be corrupted by blotches. As the restoration filter, were employ a spatiotemporal fuzzy filter whose response is adaptively controlled according to a fuzzy rule defined by the incorruption probability. The fuzzy filter is composed of the two different filter of the identity filter and the spatiotemporal directional-weighted-mean filter, and will put out an intermediate value between the original input brightness and the directional-weighted-mean brightness. We design the fuzzy rule in advance by a standard supervised learning fuzzy rule in advance by a standard supervised learning method. The computer simulations are presented.

• ETRI Journal
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• 제39권1호
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• pp.76-86
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• 2017

In this study, we propose an automatic contrast enhancement method based on transfer function modification (TFM) by histogram equalization. Previous histogram-based global contrast enhancement techniques employ histogram modification, whereas we propose a direct TFM technique that considers the mean brightness of an image during contrast enhancement. The mean point shifting method using a transfer function is proposed to preserve the mean brightness of an image. In addition, the linearization of transfer function technique, which has a histogram flattening effect, is designed to reduce visual artifacts. An attenuation factor is automatically determined using the maximum value of the probability density function in an image to control its rate of contrast. A new quantitative measurement method called sparsity of a histogram is proposed to obtain a better objective comparison relative to previous global contrast enhancement methods. According to our experimental results, we demonstrated the performance of our proposed method based on generalized measures and the newly proposed measurement.

• International Journal of Computer Science & Network Security
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• 제22권1호
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• pp.1-6
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• 2022

Exploration has always been an instinct of humans, and underwater life is as fascinating as it seems. So, for studying flora and fauna below water, there is a need for high-quality images. However, the underwater images tend to be of impaired quality due to various factors, which calls for improved and enhanced underwater images. There are various Histogram Equalization (HE) based techniques which could aid in solving these issues. Classifying the HE methods broadly, there is Global Histogram Equalization (GHE), Mean Brightness Preserving HE (MBPHE), Bin Modified HE (BMHE), and Local HE (LHE). Each of these HE extensions have their own pros and cons and thus, by considering them we have considered BBHE, CLAHE, BPDHE, BPDFHE, and DSIHE enhancement algorithms, which are based on Mean Brightness Preserving HE and Local HE, for this study. The performance is evaluated with non-reference performance measures like Entropy, UCIQE, UICM, and UIQM. In this study, we apply the enhancement algorithms on 300 images from the UIEB benchmark dataset and then apply the techniques of cascading fusion on the best-performing algorithms.

• 방송공학회논문지
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• 제22권5호
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• pp.608-617
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• 2017

영역 분리에 의한 명암대비 방법들이 제안되어 왔지만 영상의 히스토그램에 따라 과포화 되는 부작용이나 밝기 값 보존과 명암대비 효과의 상반 관계에 대한 개선이 필요하다. 본 논문은 다양한 히스토그램에서도 명암 대비가 개선 되도록 영역 분리 시 각 서브 영역이 가우시안 분포를 갖도록 분리하고 영역별 평활화하는 명암 대비 방법을 제안 한다. 영역 분리는 $L^*a^*b^*$ 컬러 공간에서 K-평균 방법과 기대-최대 방법에 의해 영역맵과 확률맵을 생성하며 영역별 히스토그램 평활화 방법은 영역간 히스토그램 중복 최소를 위해 평균값 이동과 영역 분리에서 생성된 확률맵을 변환 함수에 활용함으로써 영역별 밝기값을 보존 하였다. 실험은 기존의 명암 대비 방법들과 평균 밝기 차이와 평균 엔트로피 값을 이용하여 밝기 변화가 적고 영상의 세부 정보가 표현됨에 의한 명암대비 개선을 보인다.

• International Journal of Costume and Fashion
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• 제5권2호
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• pp.46-54
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• 2005

The Purpose of this research was focused on analyzing how costume was exactly researched for film in comparison with the original Renaissance costume, and how to change the degree of brightness and chroma in costume of two films, 'Shakespeare in Love' and 'Elizabeth: The Virgin Queen'. For these purpose, each costume of main seven scenes was analyzed in terms of silhouette, detail, and trimming. Color image, brightness and chroma of costume were compared with the color chip data from Samsung Design Net. As results, costume from two films had exactness in historical research. but the original costumes were modernly changed by the purpose of director. Color image of costume were used proper colors for the characteristic of the story. Costumes of heroine was numerically changed at the degree qf the brightness and chroma through story-going. By this change, director could effectively give dramatic rhythm for the story. The limitation of this research was that color analysis had been conducted on the screen, and this fact might mean the original colors of film might be different from those of screen.