to polychromatic colors such as red or blue or other color in the embodiment the codes represented by the bars s 0 s 1 s 9 are described as follows the bar s 0 represents number u201c 0 u201d the bar s 1 represents number u201c 1 u201d the bar s 2 represents number u201c 2 u201d the bar s 3 represents number u201c 3 u201d the bar s 4 represents number u201c 4 u201d the bar s 5 represents number u201c 5 u201d the bar s 6 represents number u201c 6 u201d the bar s 7 represents number u201c 7 u201d the bar s 8 represents number u201c 8 u201d and the bar s 9 represents number u201c 9 u201d in other embodiments the codes represented by the bars s 0 s 1 s 9 may be changed as needed the bars s 0 s 1 s 9 can respectively represent the letters u201c a u201d u201c b u201d u201c c u201d u201c d u201d u201c e u201d u201c f u201d u201c g u201d u201c h u201d u201c i u201d u201c j u201d referring to fig2 the scanning device 200 includes a processing unit 20 a power supply 21 a switch unit 22 and a plurality of scanning units 23 the power supply 21 is electrically connected to the processing unit 20 and the switch unit.