Eun-Su Kim

Optimal Piece Linear Segments of Gamma Correction for CMOS Image Sensors

The gamma correction for the CMOS image sensors are implemented by the method of piecewise linear approximation through a look-up table. In this paper, we propose a quantitative criterion to select the piece linear segment with the same output interval for the reduction of the error between the value of piece linear approximation and gamma correction. After the gamma correction is implemented, the average error occurred by implementing color interpolation in each segment is a basis for the optimum selecting of the piece linear segment of the gamma correction for the CMOS image sensors.

Adaptive Colorimetric Characterization of Camera for the Variation of White Balance

The RGB signals generated by different cameras are not equal for the same scene. Therefore, cameras are characterized based on a 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. Yet, this involves tedious experiments to obtain a camera transfer matrix under various white balance points for the same camera. Accordingly, the current paper proposes a new method for obtaining camera transfer matrices under different white balances using a 3 x 3 camera transfer matrix under a specific white balance point.

MPEG-2 test stream with static test patterns in DTV system

MPEG-2 test stream for evaluation the static picture quality of digital television (DTV) should meet both good picture quality and stable bit rate. In this paper, we present a method for generating a high quality test stream to evaluate the static picture quality in DTV receiver. The proposed method is suitable for encoding the static test pattern, such as multiburst and crosshatch, and is based on user-defined quantization and adaptive zero stuffing algorithm. The user-defined quantization is suitable for minimizing the quantization error, which is the reason of degradation of picture quality, and the adaptive zero stuffing algorithm is used to solve the overflow of video buffer verifier (VBV) buffer while encoding process by MPEG-2 encoder. Experimental results show that the average PSNR and the bit rate of the proposed method have more efficient and stable than those of the conventional.

The Design of an LCD System Based on the Quantitative Analysis for Enhancement of the Motion Picture Quality

SUMMARY The pulsed backlight system has been introduced for reducing motion blurs of LCDs in high motion pictures. But applying the pulsed backlight, full screen flicker and inconsistency of transmissivity for entire frame at a lightening time should be considered. This paper discusses the analysis of blurs in high motion pictures and proposes the design method for more suitable display terminal of LCDs.

DTV lip-sync test using time indexed audio and video signals without effect on program

The paper concentrates on a lip-sync test for DTV with respect to audio and video signals using the digital bitstream. We propose a new lip-sync test method which does not affect the current program by use of the TATS (transient effect area test signals) and an additional sub-channel audio signal. The experimental result shows that the time difference between the audio and video signals can be easily measured by a captured oscilloscope waveform at any time.

A novel CAM for the luminance levels in the same chromaticity viewing conditions

In this paper, we propose the chromatic adaptation model (CAM) for the Variations of the Luminance Levels in the same Chromaticity Viewing Conditions. The proposed model is obtained by the transform the test colors of the high luminance into the corresponding colors of the low luminance. In the proposed model, the optimal coefficients are obtained from the corresponding colors data of the Breneman’s experiments. In the experimental results, we confirmed that the chromaticity errors between the predicted colors by the proposed model and the corresponding colors of the Breneman’s experiments are 0.004 in u ′v ′ chromaticity coordinates. The prediction performance of the proposed model is excellent because this error is the threshold value that two adjacent color patches can be distinguished.

Signal processing for digital image enhancement considering APL in PDP

In this paper, a method for improvement of image quality using the error diffusion which considers the APL process is proposed. In the proposed method, the APL process is performed before the error diffusion process. Simulation results showed that the proposed method has better performances for resolution in images and CCT uniformity according to each grayscale than the conventional method.

Adaptive colorimetric characterization of digital camera with white balance

A camera is an effective tool in capturing images for colorimetric use. However, the RGB signals generated by different cameras are not equal for the same scene. Therefore, cameras are characterized based on a CIE standard colorimetric observer. This paper proposes a new method for obtaining camera transfer matrices under different white balances using a 3×3 camera transfer matrix under a specific white balance point. As such, the proposed methods enables a camera transfer matrix under any other white balance to be obtained using the colorimetric coordinates for the phosphor primaries derived from a 3×3 linear transfer matrix under a certain white balance point. Experimental results confirmed that the proposed method produced a 3×3 linear transfer matrix under any other white balance with a reasonable degree of accuracy compared with the transfer matrix obtained by the conventional method.