运用彩色图像色调、饱和度、强度（HSI）模型的H分量进行彩色图像阈值分割是一个新的彩色图像阈值化方式。考虑到H分量是一个圆形直方图，将圆形直方图断开为线性直方图，然后采用线性直方图阈值分割法进行阈值选取是一种有效途径。在信息论中，信息能量是Shannon熵的对偶，首先引入线性概率分布的累积分布信息能量概念，基于此来确定圆形直方图的断点；然后给出线性直方图上的信息能量阈值法，并基于此实现H分量圆形直方图的阈值选取。相比于基于对数运算的Shannon熵阈值选取准则，基于平方运算的信息能量阈值选取准则具有表述简单、运算速度快的优点。

To study the efficacy and side effects of antitumor drug by the method of Raman spectroscopy, the cancerous (SGC-7901) and normal (GES-1) gastric cells were treated with 0, 25-, 100-, and 200-mg/L 5-fluorouracil (5-Fu) for 24 h, respectively, then Raman spectra of cells were recorded. The excitation wavelength was 514.5 nm and the Raman spectra in the region of 500-1800 cm-1 were recorded. For the gastric cancer cells, as the concentration of 5-Fu increases, the band at 1094 cm-1 attributed to the symmetric stretching vibration mode of PO^(2)_(-) in the DNA backbone gradually decreases, and the intensity ratio of the band at 1315 cm-1 to that at 1340 cm-1 (I1315/I1340) shows the ascending trend, and the ratio of the band area at 1655 cm-1 to that at 1450 cm-1 (A1655/A1450) shows the slight ascending trend. For the normal gastric cells, these peaks also appear changes, however, the changes are weaker than those for the cancer cells. In SGC-7901 cells, 5-Fu can interfere with the DNA synthesis and result in the reduction of the DNA content. Besides, it can affect the unsaturation degree of the hydrocarbon chains and alter the external environment of guanine and adenine residues in cancer cells. The changes of Raman spectra for normal gastric cells reveal the side effect of 5-Fu.

Micro-Raman spectroscopy is employed to identify the normal and malignant human stomach cells. For the cancer cell, the reduced intensity of the Raman peak at 1250 cm^(-1) indicates that the protein secondary structure transforms from β-sheet or disordered structures to α-helical, while the increased intensity of the symmetric PO2 stretching vibration mode at 1094 cm^(-1) shows the increased DNA content. The ratio of the intensity at 1315 cm^(-1) to that at 1340 cm^(-1) reduces from 1.8 for the normal cell to 1.1 for the cancer cell in the course of canceration, and the ratio of the intensity at 1655 cm^(-1) to that at 1450 cm^(-1) increases from 1.00 for the cancer cell to 1.26 for the normal cell which indicates that the canceration of stomach cell may induce saturation of the lipid chain.