Abstract: To improve noisepmof ability and stability of Lempel-Ziv complexity (LZC), LZC is calculated by an equiprobable coarse graining method. Relation between threshold of bi-quantified coarse graining and LZC is analyzed. An anti-jamming test is performed with 87 series generated by Logistic map. Correlation coefficients and relative variance coefficients of LZC series before and after noise inject are used to measure noiseproof ability of LZC indexes. 10 electroencephalograms are used to test stability of LZC. It shows that with equiprobable coarse graining, correlation coefficients are more than 0.998, relative variance coefficients are smaller and stability of LZC of electroencephalogram is good.

Key words: complexity, coarse graining, equal probability, logistic map, electroencephalogram