Abstract: A visual-based contactless communication device adapted to communicate with one or more visual-based contactless devices includes a photographic device for photographing image data displayed by one or more visual-based contactless communication devices; a center control device for identifying predetermined information in the image data, producing response information according to the predetermined information and generating effective image data identifiable by one or more visual-based contactless communication devices according to the response information or specified information; and a display device for displaying the effective image data to be photographed by one or more visual-based contactless communication devices; wherein when two visual-based contactless communication devices communicate with each other, one displays the effective image data with the response information after identifying the predetermined information, and the other proceeds with subsequent communication only after identifying the eff

Abstract: A data encoding method is provided. The data has several bytes, and each byte has n bits. The data encoding method includes the following steps. First, a specific value is defined. Next, the data is divided into one or several data blocks each having m bytes, wherein m?2n?2. Following that, a replacing value, not appearing in the m bytes of the data block, is obtained from each data block respectively, wherein the replacing value is not equal to the specific value. Then, the values of the bytes being the specific value are replaced to the replacing value in the m bytes of each data bock respectively. Afterwards, a starting byte is allocated at the start of each data block, and the replacing value is stored to the starting byte so as to obtain the data block being encoded respectively. Each data block being encoded has m+1 bytes.

Abstract: A data encoding method is provided. The data has several bytes, and each byte has n bits. The data encoding method includes the following steps. First, a specific value is defined. Next, the data is divided into one or several data blocks each having m bytes, wherein m?2n?2. Following that, a replacing value, not appearing in the m bytes of the data block, is obtained from each data block respectively, wherein the replacing value is not equal to the specific value. Then, the values of the bytes being the specific value are replaced to the replacing value in the m bytes of each data bock respectively. Afterwards, a starting byte is allocated at the start of each data block, and the replacing value is stored to the starting byte so as to obtain the data block being encoded respectively. Each data block being encoded has m+1 bytes.