Two kinds of compression-type vertex chain code are proposed. According to the characteristic that massive continuous two-vertex numbers are usually contained in an image boundary’s vertex chain code

in actual coding process

1 and 3 are replaced by 0 and 9 separately

and 1 to 8 are used to express 2

a new dynamic vertex chain code is presented. The edge’s vertexe numbers of a figure are divided into four types: 1

2

3 and the combination of 1 and 3

based on which the top bit area and the low bit area of one byte are used to express the number and its continuous quantity of the code separately

a new compression type chain code is studied. Compared with the current vertex chain codes based on an efficiency-evaluation method

the results indicate that the new vertex chain codes not only have 50%～70% coding compression-ratio

moreover their coding or decoding efficiency is enhanced by 10%～40%

namely

their decoding real-time is better.