• Title/Summary/Keyword: White balance

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A White Balance System for PDP TV (PDP TV에서 인간 시각을 고려한 최적의 White Balance 구현)

  • 정기백;구본철
    • Proceedings of the IEEK Conference
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    • 2003.11a
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    • pp.363-366
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    • 2003
  • We propose the system that automatically adjusts the white balance on display products to a standard value according to several nations. We replace manual or semi-auto method with fully automatic method using windows application program. And we use RS-232C serial interface to communicate PC with display products which we want to adjust white balance. The PC generates patterns for measuring color information and Color Analyzer measures color and brightness. This value is transmitted through RS-232C serial interface to PC. The PC's algorithm analyzes this information and then decides which RGB Gain value is best for optimal white balance. This RGB Gain value is transmitted through RS-232C serial interface to display products. The modified color value is measured again and feed back to PC. This sequence is repeated until optimum white balance is obtained.

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A new automatic white balance algorithm using non-linear gain (Non-linear gain을 적용한 Automatic White Balance기법)

  • Yun, Se-Hwan;Kim, Jin-Heon
    • Proceedings of the KIEE Conference
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    • 2006.04a
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    • pp.27-29
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    • 2006
  • In this paper, we propose a new method of automatic white balance which is one of the image signal processing techniques. Our method is conceptually based on gray world assumption. However, while previous methods generate linear results as multiplying pixel values by a gain, our method generates non-linear results using the feature of B-Spline curves. The two merits of deriving non-linear results are preventing AWB failure from transforming strong color of high level into wrong color and well preserving original contrast of an input image.

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Effect of Auditory Stimulus using White Nosie on Dynamic Balance in Patients with Chronic Stroke during Walking

  • Lim, Hee Sung;Ryu, Jiseon;Ryu, Sihyun
    • Korean Journal of Applied Biomechanics
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    • v.30 no.4
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    • pp.301-309
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    • 2020
  • Objective: This study aimed to investigate the effect of white noise on dynamic balance in patients with stroke during walking. Method: Nineteen patients with chronic stroke (age: 61.2±9.8 years, height: 164.4±7.4 cm, weight: 61.1±9.4 kg, paretic side (R/L): 11/8, duration: 11.6±4.9 years) were included as study participants. Auditory stimulus used white noise, and all participants listened for 40 minutes mixing six types of natural sounds with random sounds. The dynamic balancing ability was evaluated while all participants walked before and after listening to white noise. The variables were the center of pressure (CoP), the center of mass (CoM), CoP-CoM inclined angle. Results: There is a significant increase in the antero-posterior (A-P) CoP range, A-P inclination angle, and gait speed on the paretic and non-paretic sides following white noise intervention (p<.05). Conclusion: Our findings confirmed the positive effect of using white noise as auditory stimulus through a more objective and quantitative assessment using CoP-CoM inclination angle as an evaluation indicator for assessing dynamic balance in patients with chronic stroke. The A-P and M-L inclination angle can be employed as a useful indicator for evaluating other exercise programs and intervention methods for functional enhancement of patients with chronic stroke in terms of their effects on dynamic balance and effectiveness.

Novel Auto White Balance Algorithm Using Adaptive Color Sampling Based on $CIEL^*a^*b^*$ color space for Mobile Phone Camera ($CIEL^*a^*b^*$ 색 공간에서 적응적 컬러 샘플링을 이용한 Mobile Phone 카메라용 자동화이트 밸런스 알고리즘)

  • Kim, Kyung-Rin;Son, Kyoung-Soo;Ha, Joo-Young;Kim, Sang-Choon;Kang, Bong-Soon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.8
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    • pp.1356-1362
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    • 2008
  • In this paper. we propose a novel auto white balance algorithm which is one of the representative functions on cameras. White balance is the process of removing unrealistic color casts, which will make the captured white objects appear white. For white balance, we employ $CIEL^*a^*b^*$ color space which is the most complete color model available and is conventionally used to describe all the colors visible to the human eye and estimate the color difference on white objects with distribution of the image which is called the reference white estimation. For accuracy, we form groups or sets of pixels that are altered by the light sources and other elements. Moreover, Standard group is decided by judgment of specific-case images with the information of groups. Then, the reference white estimation is performed by the color sampling which is to choose all the accumulated pixels contained within the standard group. The color gain for image compensation by considering the color saturation is also computed. the proposed algorithm provides a significant performance.

Efficient Algorithms on White Balance for ISP (ISP를 위한 효율적인 White Balance 알고리즘)

  • 정영식;최영철;장영조
    • Proceedings of the Korean Information Science Society Conference
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    • 2002.10e
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    • pp.550-552
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    • 2002
  • 외부 조명의 밝기나 종류등에 영향으로 CMOS 영상센서에서 출력되는 색상과 원색과 차이가 있다. 이러한 왜곡된 색상을 Red, Green, Blue와 휘도를 이용하여 점차적으로 원래의 색으로 표현하는 과정이 White Balance이다. 따라서 이러한 과정이 없을 시에는 우리의 눈으로 보는 것과 영상장치를 통해서 모니터에 표시되는 영상의 색상이 차이가 생긴다. 본 논문에서는 WB의 몇 가지 알고리즘을 보이고 비교/분석하여 알고리즘의 장ㆍ단점을 파악하여 각 상황에 따른 알고리즘의 선택을 제시하였다.

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Single Tone Detection Algorithm for Improve on Auto White Balance of Mobile Phone Camera (모바일 폰 카메라의 자동백색보정 성능향상을 위한 단색영상 검출 알고리즘)

  • Kim, Kyung-Rin;Jang, Won-Woo;Kim, Joo-Hyun;Yang, Hoon-Gee;Kang, Bong-Soon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.7
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    • pp.1292-1302
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    • 2009
  • In this paper, we proposed Single Tone Detection Algorithm for prevent decoloration and color distortion of single tone image in auto white balance of mobile phone camera. Conventional auto white balance which accomplish very well using complex color images, but there are some problems if input images are single tone image or included large part of single tone. If input images are singlet one, or included large part of single tone, which cause decoloration or distorted color in output images. In this paper, we proposed single tone detection algorithm using color histogram data for solve decoloration or distorted color problems. If this algorithm is applied to auto white balance, it will be improvement in auto white balance.

Adaptive White Point Extraction based on Dark Channel Prior for Automatic White Balance

  • Jo, Jieun;Im, Jaehyun;Jang, Jinbeum;Yoo, Yoonjong;Paik, Joonki
    • IEIE Transactions on Smart Processing and Computing
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    • v.5 no.6
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    • pp.383-389
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    • 2016
  • This paper presents a novel automatic white balance (AWB) algorithm for consumer imaging devices. While existing AWB methods require reference white patches to correct color, the proposed method performs the AWB function using only an input image in two steps: i) white point detection, and ii) color constancy gain computation. Based on the dark channel prior assumption, a white point or region can be accurately extracted, because the intensity of a sufficiently bright achromatic region is higher than that of other regions in all color channels. In order to finally correct the color, the proposed method computes color constancy gain values based on the Y component in the XYZ color space. Experimental results show that the proposed method gives better color-corrected images than recent existing methods. Moreover, the proposed method is suitable for real-time implementation, since it does not need a frame memory for iterative optimization. As a result, it can be applied to various consumer imaging devices, including mobile phone cameras, compact digital cameras, and computational cameras with coded color.

Smartphone Use at Night Affects Melatonin Secretion, Body Temperature, and Heart Rate

  • Na, Nooree;Choi, Hojun;Jeong, Kyeong Ah;Choi, Kyungah;Choi, Kyungsun;Choi, Chulhee;Suk, Hyeon-Jeong
    • Science of Emotion and Sensibility
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    • v.20 no.4
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    • pp.135-142
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    • 2017
  • In the present study, we investigated the physiological effects of smartphone use at night when the display luminance and white balance were differently manipulated. Two levels of luminance and two types of white balance were combined to form four types of displays. Subjects were instructed to use smartphones between 23:00 to 01:00 twice a week for two weeks, and for each trial, subjects were given one of the four display types. Melatonin concentration in the saliva, body temperature and heart rate were measured before and after each experiment. The experimental result showed that the low luminance display supported melatonin secretion and thermoregulation compared to the high luminance display. With regard to the white balance, higher melatonin level was observed when using the display that filtered blue light. The low luminance display together with yellowish tint best supported restful sleep at night in terms of every physiological response. This study collectively demonstrates that bright and blue light emitted from smartphone displays adversely affect melatonin secretion, body temperature, and heart rate, and therefore, suggests the use of a display with low luminance or a display that filters blue light for a restful sleep at night.

Flesh Tone Balance Algorithm for AWB of Facial Pictures (인물 사진을 위한 자동 톤 균형 알고리즘)

  • Bae, Tae-Wuk;Lee, Sung-Hak;Lee, Jung-Wook;Sohng, Kyu-Ik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.11C
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    • pp.1040-1048
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    • 2009
  • This paper proposes an auto flesh tone balance algorithm for the picture that is taken for people. General white balance algorithms bring neutral region into focus. But, other objects can be basis if its spectral reflectance is known. In this paper the basis for white balance is human face. For experiment, first, transfer characteristic of image sensor is analyzed and camera output RGB on average face chromaticity under standard illumination is calculated. Second, Output rate for the image is adjusted to make RGB rate for the face photo area taken under unknown illumination RGB rate that is already calculated. Input tri-stimulus XYZ can be calculated from camera output RGB by camera transfer matrix. And input tri-stimulus XYZ is transformed to standard color space (sRGB) using sRGB transfer matrix. For display, RGB data is encoded as eight-bit data after gamma correction. Algorithm is applied to average face color that is light skin color of Macbeth color chart and average color of various face colors that are actually measured.

Color temperature transformation of high dynamic range images

  • Kim, Yoon-Ah;Byun, Seong-Chan;Lee, Byung-Uk
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2009.01a
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    • pp.334-336
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    • 2009
  • Estimation and correction of color temperature of digital images are basis of white balance adjustment after image acquisition stage. White balance is one of the most important image processing techniques for subjective image quality enhancement. Correction of color temperature is applied for white balance adjustment or for changing the mood of a picture. A picture taken under the daylight can be changed to have a mood of sunset or cloudy day, for example. We evaluate color temperature transformation of high dynamic range images in linear and log domain, and we conclude that linear domain transformation shows better results.

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