• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.2
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• pp.23-34
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• 2004

Video camera can be a useful tool to capture images for use in colorimeter. However the RGB signals generated by different video camera are not equal for the same scene. The video camera for use in colorimeter is characterized based on the CIE standard colorimetric observer. One method of deriving a colorimetric characterization matrix between camera RGB output signals and CIE XYZ tristimulus values is least squares polynomial modeling. However it needs tedious experiments to obtain camera transfer matrix under various white balance point for the same camera. In this paper, a new method to obtain camera transfer matrix under different white balance by using 3${\times}$3 camera transfer matrix under a certain white balance point is proposed. According to the proposed method camera transfer matrix under any other white balance could be obtained by using colorimetric coordinates of phosphor derived from 3${\times}$3 linear transfer matrix under the certain white balance point. In experimental results, it is demonstrated that proposed method allow 3${\times}$3 linear transfer matrix under any other white balance having a reasonable degree of accuracy compared with the transfer matrix obtained by experiments.

• Journal of Power System Engineering
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• v.20 no.3
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• pp.64-73
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• 2016

In this research work, an algorithm development on tracking end-point of aerial work platform with jib profile and bend-linked boom was carried out to find the X, Y and Z direction value using coordinate transformation matrix. This matrix consists of device status value(length and angle) based on camera position axis, which are sent from device controller PLUS+1 by CAN protocol. These values are used to measure the distance and angle from the camera to the end-point. Using these distance and angle value, monitoring system controls FAN/TILT/ZOOM status of camera to get an adequate scene of workplace. This program was written in Java, C# and C for mobile device. These results provide the information to the aerial work device for secure operation.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.4 s.310
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• pp.9-18
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• 2006

In the digital camera system, CMOS image sensor (CIS) is widely used because its size and weight become smaller and power consumption becomes lower. However, there are common problems that colors of the recorded image do not match those of the photographed object and that spectral sensitivity of the CIS used in different cameras varies largely in each case. Therefore, color correction is needed because the spectral sensitivity of the CIS in each color is neither the same color component for most standard colors nor the appropriate color representation for any output devices. In the conventional method, a color correction is empirically obtained by a large number of iterative experiments, but the result is not so satisfied. In this paper, a new method to obtain the efficient color correction matrix for digital camera using CIS is proposed. We obtain camera transfer matrix under the certain white-balance point, and color correction matrix that makes the transfer characteristic of digital camera close to the transfer characteristic of ideal camera is obtained. The experimental results show that the transfer characteristic of digital camera by the proposed method is close to that of the ideal camera. In addition, the image quality of pictures of digital camera using the proposed method is dramatically improved.

• Korean Journal of Optics and Photonics
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• v.15 no.2
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• pp.183-189
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• 2004

As high quality digital cameras become readily available, digital cameras are being used not only for simple picture recording but also as information storing media in various fields. However, due to the fact that the spectral responses of the camera sensors are different from color matching functions of the CIE standard observer, the color can not be measured using these cameras. This study shows a method for converting camera image to sRGB image, in which color information is preserved. The transfer matrix between camera output signals and CIE stimulus values was determined using a multiple regression method with Macbeth ColorChecker as target colors. The CIE stimulus values for camera output signals can be mapped with a transfer matrix, and these values are converted to sRGB signals. As the result of testing a Kodak DC220 digital camera, the average color difference of Macbeth ColorChecker between true and displayed colors was 2.1 $\Delta$ $E_{ab}$ $^{*}$.$^{*}$.

• 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.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.3
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• pp.27-38
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• 2017

This Paper Presents a Method for Stitching a Large Number of Images Recorded by a Large Number of Individual Users Through a Cellular Phone Camera at a Venue. In Contrast to 360 Camera Solutions that Use Existing Fixed Rigs, these Conditions must Address New Challenges Such as Time Synchronization, Repeated Transformation Matrix Calculations, and Camera Sensor Mismatch Correction. In this Paper, we Solve this Problem by Updating the Transformation Matrix Using Time Synchronization Method Using Audio, Sensor Mismatch Removal by Color Transfer Method, and Global Operation Stabilization Algorithm. Experimental Results Show that the Proposed Algorithm Shows better Performance in Terms of Computation Speed and Subjective Image Quality than that of Screen Stitching.

• Journal of Korea Multimedia Society
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• v.13 no.5
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• pp.641-650
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• 2010

Color image sensors (CIS) output color images through image sensors and image signal processing. Image sensors that convert light to electrical signal are divided into CMOS image sensor and CCD image sensor according to transferring method of signal charge. In general, a CIS has RGB output signals from tri-stimulus XYZ of the scene through image signal processing. This paper presents an adaptive colorimetric analysis method to obtain chromaticity and luminance using CIS under various environments. An image sensor for the use of colorimeter is characterized based on the CIE standard colorimetric observer. We use the method of least squares to derive a colorimetric characterization matrix between camera RGB output signals and CIE XYZ tristimulus values. We first survey the camera characterization in the standard environment then derive a SGL(shutter-gain-level) function which is relationship between luminance and auto exposure (AE) characteristic of CIS, and read the status of an AWB(auto white balance) function. Then we can apply CIS to measure luminance and chromaticity from camera outputs and AE resister values without any preprocessing. Camera RGB outputs, register values, and camera photoelectric characteristic are used to analyze the colorimetric results for real scenes such as chromaticity and luminance. Experimental results show that the proposed method is valid in the measuring performance. The proposed method can apply to various fields like surveillant systems of the display or security systems.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.1
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• pp.37-45
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• 2008

This paper proposes a half-silvered mirror display system designed to demonstrate useful information about things on display into the air. It helps the spectators gain quick access to information near the area where the things are put on display. This paper deals with three matters: First, tracking based on camera images created in real time enables the provision of information about the things that are both still and moving. Second, as information is output based on the real-time coordinates of things on display, the parallel processing-based tracking algorithm is used to ensure smooth transfer. Third, a half-mirror is placed in front of the display area to establish an augmented reality system and visual distortion caused by mirror angle is adjusted by the reflection transformation matrix. The objectives of this system are to arouse the spectators' interest in things on display and offer easy and quick access to information about them.