고서화에 찍힌 도장 이미지의 디지털 분리 방법 - 해동 백계산 옥룡사 증시 선각국사 비명 병서를 사례를 중심으로 -

Abstract

The purpose of this study is to decipher the seal on Haedong Baekgyesan Okryongsa jeungsi Seongakguksa bimyung byungseo which has been stored in the Suncheon Songgwangsa Museum. So far, it has been impossible to decipher the steal due to the overlapping of the letters on the paper. To overcome this problem, we employed a technique using a digital camera and a computer. First, we digitized the seal image using a high-performance digital camera, then classified it as four parts according to color density; white paper, black letters, red seal and overlapped seal with letters. Classification was done using correlation between the color, density and brightness of the seal and those of the paper. In this process, digital techniques were used, such as highlighting and weakening each area (paper, seal, letter, seal + letter) in a state good for separation. Then, we adjusted the color and luminance of the seal to a desired condition for digital separation, and the density and contrast were adjusted differently by digitally processing the density, luminance, and color of the paper and seal. The extraction was successful by changing the concentration and contrast of the sealed inju. Consequently, we successfully deciphered the seal on the Book.