MACHINE-READABLE SYMBOLS

1 .- 140 . (canceled)

141 . A machine-readable symbol, comprising:

a first machine-readable symbol instantiated on an object, said machine-readable symbol having a number of code elements that can be read by one or more methodologies to yield code values, said code elements constituting a basic unit of said symbol that yields said value independent of any other code element and free from decoding any other code value of said machine-readable symbol;

said code elements comprising at least three non-binary code elements including a first code element having a first value, a second code element having a second value different than said first value, and a third code element having a third value different from said first and second values.

142 . A machine-readable symbol as set forth in claim 141 , wherein said code elements include four non-binary code elements having four different values.

143 . A machine-readable symbol as set forth in claim 141 , wherein each of said non-binary code elements are readable by a combination of two different methodologies.

144 . A machine-readable symbol as set forth in claim 143 , wherein each of said two different methodologies involves an optical characteristic.

145 . A machine-readable symbol as set forth in claim 143 , wherein said two different methodologies comprise a reflectance methodology and a topographic methodology.

146 . A machine-readable symbol as set forth in claim 145 , wherein said topographic methodology yields information concerning a depth of a code element under analysis.

147 . A machine-readable symbol as set forth in claim 145 , wherein said two different methodologies yield a quaternary symbol value set composed of first and second states of said first methodology and first and second states of said second methodology.

148 . A machine-readable symbol as set forth in claim 147 , wherein quaternary symbol value set includes values corresponding to white-surface, white-deep, black-surface, and black-deep.

149 . A machine-readable symbol as set forth in claim 141 , wherein the first machine-readable symbol comprises a barcode printed on the surface of the object.

150 . A machine-readable symbol as set forth in claim 141 , wherein the first machine-readable symbol comprises a barcode printed on a conformal layer applied over the surface of the object.

151 . A method for decoding a first machine-readable symbol, comprising the steps of:

acquiring an image of the machine-readable symbol;

identifying an image portion of said image corresponding to an element of said machine-readable symbol;

processing the identified image portion using one or more methodologies to determine a code value from a value set corresponding to the code element, said value set having at least three possible values.

152 . A method as set forth in claim 151 , wherein said value set includes at least four different values.

153 . A method as set forth in claim 151 , wherein said step of processing comprises:

processing the image to separately evaluate first and second characteristics of the image portion:

applying a first methodology to obtain first information from the evaluated first characteristic; and

applying a second methodology to obtain second information from the second evaluated characteristic; and

using the first information and the second information to determine said code value from said set of code values.

154 . A method set forth in claim 153 , wherein each of said two different methodologies involves an optical characteristic.

155 . A method as set forth in claim 153 , wherein said two different methodologies comprise a reflectance methodology and a topographic methodology.

156 . A method as set forth in claim 155 , wherein said topographic methodology yields information concerning a depth of a code element under analysis.

157 . A method as set forth in claim 155 , wherein said two different methodologies yield a quaternary symbol value set composed of first and second states of said first methodology and first and second states of said second methodology.

158 . A method as set forth in claim 157 , wherein quaternary symbol value set includes values corresponding to white-surface, white-deep, black-surface, and black-deep.

159 . A method as set forth in claim 151 , wherein the first machine-readable symbol comprises a barcode printed on the surface of the object.

160 . A method as set forth in claim 151 , wherein the first machine-readable symbol comprises a barcode printed on a conformal layer applied over the surface of the object.