A method to extract main palm lines from high resolution palm images(5312×2988) is presented in this paper in order to extract palm lines more easily just by using only an image of a hand by using Sobel mask and a mosaic-like method. At first, RGB information is converted to YCbCr color model which is less sensitive to brightness change. The palm region is extracted by simple thresholding using widely known skin color information of Y: 0~255, Cb: 77~255, Cr: 133~255. After that, histogram stretching is applied to the palm region and edges extracted by using Sobel edge operator. Final binary image is acquired by thresholding the edge image using a threshold. 1/4, 1/9, 1/16 and 1/25 compressed images are acquired for the histogram stretched image of the original image. Applying the same edge Received (January 6, 2016), Review Result (January 20, 2016) Accepted (January 27, 2016), Published (March 31, 2016) School of Electronics Engineering, Kyungpook National Univ., 80 Daehakro, Bukgu, Daegu, 41556, S. Korea email: ljh109011@gmail.com (Corresponding Author) School of Electronics Engineering, Kyungpook National Univ., 80 Daehakro, Bukgu, Daegu, 41556, S. Korea email: dhc@ee.knu.ac.kr Palm Lines Extraction on a High Resolution Image using Mosaic-like Method Copyright c 2016 HSST 10 extraction operator and thresholding, binary images are obtained for each compressed image. After then each compressed images are overlapped by applying a mosaic-like method to obtain final palm line image. Experimental result shows that the proposed method highlights major palm lines and suppresses unnecessary noises.