A bar-code symbol consists of alternating dark and light bars, starting with a dark bar on the left. Each bar is a number of units wide. Figure 1 shows a bar-code symbol consisting of 4 bars that extend over 1+2+3+1=7 units.
Figure 1: Bar-code symbol over 7 units (see top) with 4 bars (see bottom)
In general, the bar code BC(n,k,m) is the set of all symbols with k bars that together extend over exactly n units, each bar being at most m units wide. For instance, the symbol in Figure 1 belongs to BC(7,4,3) but not to BC(7,4,2).
0: 1000100 | 8: 1100100
1: 1000110 | 9: 1100110
2: 1001000 | 10: 1101000
3: 1001100 | 11: 1101100
4: 1001110 | 12: 1101110
5: 1011000 | 13: 1110010
6: 1011100 | 14: 1110100
7: 1100010 | 15: 1110110
Figure 2: All symbols of BC(7,4,3)
Figure 2 shows all 16 symbols in BC(7,4,3). Each `1' represents a dark unit, each `0' a light unit. The symbols appear in lexicographic (dictionary) order. The number on the left of the colon (`:') is the rank of the symbol. The symbol in Figure 1 has rank 4 in BC(7,4,3).