Wonwoo Jang

Edge Adaptive Color Interpolation for Ultra-Small HD-Grade CMOS Video Sensor in Camera Phones

This paper proposes an edge adaptive color interpolation for an ultra-small HD-grade complementary metal-oxide semiconductor (CMOS) video sensor in camera phones that can process 720-p/30-fps videos. Recently, proposed methods with great image quality perceptually reconstruct the green component and then estimate the red/blue component using the reconstructed green and neighbor red and blue pixels. However, these methods require the bulky memory line buffers in order to temporally store the reconstructed green components. The edge adaptive color interpolation method uses seven or nine patterns to calculate the six edge directions. At the same time, the threshold values are adaptively adjusted by the sum of the color values of the selected pixels. This method selects the suitable one among the patterns using two flowcharts proposed in this paper, and then interpolates the missing color values. For verification, we calculated the peak-signal-to-noise-ratio (PSNR) in the test images, which were processed by the proposed algorithm, and compared the calculated PSNR of the existing methods. The proposed color interpolation is also fabricated with the 0.18-㎛ CMOS flash memory process.

Auto white balance system using adaptive color samples for mobile devices

This paper presents a novel auto white balance (AWB) algorithm for images based on an YCbCr color space. The proposed algorithm divides all the pixels into fourteen groups by Y luminance and CbCr color components. For accuracy, we employ an adaptive color samples that can obtain the sum of the accumulated pixels up to the standard group for estimating a degree of white objectpsilas color changes. The color samples are used for the adjustment of the relative amounts of red, green, and blue primary colors. In order to avoid a field-flicker noise of video streams, the proposed algorithm adopts infinite impulse response (IIR) filters that vary the operating speed of overall AWB system. The performance of the algorithm is also verified by implementing the hardware of the system.

A New Image-scaling Algorithm Eradicating Blurring and Ringing to Apply to Camera Phones

This paper proposes the algorithm that can implement high resolution images using a camera module at low cost. The result when using proposed algorithm is superior to that of bicubic, but the hardware structure is simpler than that of bicubic and it is equipped with the boost of high frequency to remove blurs. It also eradicates ringing effectively when removing blurs.

An image signal processor for ultra small HD video sensor with 3A in camera phones

In this paper, we propose the use of an image signal processor (ISP) for an ultra small HD grade video sensor with 3A (AWB, AE, and AF) in camera phones that can capture 720P/30fps video. In order to enhance the video quality of the systems, it is necessary to achieve the high performance of 3A. The proposed ISP is also implemented on a FPGA demonstration board.

Implementation of the Gamma (γ) Line System Similar to Non-linear Gamma Curve with 2bit Error(LSB)

Gamma correction is an essential function in every display device such as CRT, plasma TV, and TFT LCD. (Po-Ming Lee, 2005) proposed gamma (γ) correction systems are developed to reduce the difference between non-linear gamma curve produced by a typical formula and result produced by the proposed algorithm. The proposed algorithms and systems are based on the specific gamma value such as 2.2, namely the formula, f(x)=xγ and the bit width of input and out data is 10bit. In order to reduce the difference, the proposed system is using the least squares polynomial which is calculating the best fitting polynomial through a set of points which is sampled. System are consisting of continuous several kinds of equations and having their own overlap sections to get more precise. Based on the algorithm verified, the systems are implemented by using Verilog-HDL. This paper compares the latest algorithm such as proposed system with the previous that of gamma system such as existing system. The former and the latter system have 2, 2 clock latency; each 1 result per clock. Each of the error range (LSB) is -1~+1, -3~+4. Under the condition of SAMSUNG STD90 0.35 worst case, each gate count is 2,564, 2,083 gates and each maximum data arrival time is 17.52,15.56 [ns], respectively

Automatic red-eye detection and correction system for mobile sevices

This paper presents an automatic red-eye detection and correction system. In order to detect red eye, we propose to use two information sources: color around the eyes and eyes round shape. The color information is from the red, highlight, and skin masks. Eye-shape is from our proposed real-time 2-dimensional grouping algorithm called ARTS. Our correction method promises to a natural-looking result. We designed the hardware using Verilog HDL, and successfully built and tested it using an FPGA device, a USB interface board, and a two-megapixel CMOS sensor. With a TSMC 0.25-mum ASIC library, the gate count was 325,167 gates, and the maximum data arrival time was 41.8 [MHz].