Optically readable coded target

A target for providing coded data readable by an imaging apparatus, the target comprising:

• location marking means for enabling location of said target by said imaging apparatus preparatory to an imaging operation carried out by said imaging apparatus;
• said target further including at least one code marking region, said at least one code marking region having a shape comprised by at least a segment of a generally annular shape, and said at least one code marking region including circumferentially disposed code markings containing coded data which are imaged by said imaging apparatus to enable recovery of the coded data from the target during or following the imaging operation;
• said coded data being replicated in full at each of at least two different rotationally dispersed locations relative to the center of curvature of said generally annular shape thereby enabling attempted readings of the coded data by said imaging apparatus from at least two sets of replicated code markings, said location marking means having high visibility characteristics to enable identification of the location marking means by said imaging apparatus against a background;
• and
• said location marking means including at least one annular region which is substantially concentric with said at least one code marking region to enable fine location by said imaging apparatus of the center of curvature of said at least one code marking region.

A target for providing coded data readable by an imaging apparatus, the target comprising:

• location marking means for enabling location of said target by the imaging apparatus preparatory to an imaging operation carried out by said imaging apparatus;
• said target further including at least one code marking region, said at least one code marking region having a shape comprised by at least a segment of a generally annular shape, and said at least one code marking region including circumferentially disposed code markings containing coded data which are imaged by said imaging apparatus to enable recovery of the coded data from said target during or following the imaging operation;
• said coded data being replicated in full at each of at least two different rotationally dispersed locations relative to the center of curvature of said generally annular shape thereby enabling attempted readings of the coded data by said imaging apparatus from at least two sets of replicated code markings, said location marking means having high visibility characteristics to enable identification of said location marking means by said imaging apparatus against a background, said location marking means including at least one annular region which is substantially concentric with said at least one code marking region to enable fine location by said imaging apparatus of the center of said at least one code marking region;
• and
• said annular region being located at a significant radial distance from the general center of curvature of said at least one code marking region so as to facilitate identification by said imaging apparatus of the annular region, said annular region not being located at an outer peripheral edge of the target where degradation of the annular region may interfere with the imaging operation.

A target for providing coded data readable by an imaging apparatus, the target comprising:

• location marking means for enabling location of said target by said imaging apparatus preparatory to an imaging operation carried out by the imaging apparatus;
• said target further including at least one code marking region, said at least one code marking region having a shape comprised by at least a segment of a generally annular shape, and said at least one code marking region including circumferentially disposed code markings containing coded data which are imaged by the imaging apparatus to enable recovery of said coded data from said target during or following said imaging operation, said coded data being replicated in full at each of at least two different rotationally dispersed locations relative to the center of curvature of said generally annular shape thereby enabling attempted readings of the coded data by said imaging apparatus from at least two sets of replicated code markings;
• said location marking means including a central marking region located generally centrally of said at least one code marking region so that identification by said imaging apparatus of the central region of said location marking means locates the general position of the center of curvature of said at least one code marking region;
• and
• said location marking means further including at least one annular marking region radially spaced from and substantially concentric with said central marking region of the location marking means, and the identification of the annular marking region enabling fine location by the imaging apparatus of the center of curvature of said at least one code marking region.

An optically readable coded data retrieval system comprising a target for providing coded data and an imaging apparatus for identifying the target and recovering the coded data from the target, the imaging apparatus including:

• a radiation source operative to direct radiation generally towards said target;
• said target comprising location marking means for enabling location of said target by said imaging apparatus preparatory to an imaging operation carried out by said imaging apparatus;
• said target further including at least one code marking region, said at least one code marking region having a shape comprised by at least a segment of a generally annular shape, said at least one code marking region including circumferentially disposed code markings containing coded data which are imaged by said imaging apparatus to enable recovery of the coded data from the target during or following the imaging operation, and the coded data being replicated in full at each of at least two different rotationally dispersed locations relative to the center of curvature of said generally annular shape thereby enabling attempted readings of the coded data by said imaging apparatus from at least two sets of replicated code markings;
• and
• said location marking means comprising a retro-reflective material so that radiation from the radiation source of the imaging apparatus which is directed towards the target is strongly reflected back to said imaging apparatus, said imaging apparatus being operative to identify said location marking means and recover the coded data from said at least one code marking region.

An optically readable coded data retrieval system comprising:

• a target for providing coded data and an imaging apparatus for identifying said target and recovering the coded data from said target;
• said imaging apparatus including a radiation source operative to direct radiation generally towards the target;
• said target comprising location marking means for enabling location of the target by said imaging apparatus preparatory to an imaging operation carried out by said imaging apparatus, said target further including at least two code marking regions;
• each of said at least two code marking regions having a shape comprised by at least a segment of a generally annular shape, each of said at least two code marking regions including circumferentially disposed code markings containing coded data which are imaged by the imaging apparatus to enable recovery of the coded data from the target during or following said imaging operation, said at least two code marking regions sharing in common a center of curvature of said generally annular shapes and being spaced from said center of curvature at different radial distances, and each of said at least two code marking regions containing the same coded data and being located at different rotational positions relative to the center of curvature so that the coded data is replicated in full at different radial distances from the center of curvature and at least two different rotationally dispersed locations thereby enabling attempted readings of the coded data by said imaging apparatus from at least two sets of replicated code markings;
• said location marking means comprising a retro-reflective material so that radiation from said radiation source of said imaging apparatus which is directed towards said target is strongly reflected back to said imaging apparatus;
• and
• said imaging apparatus being operative to identify the location marking means and recover the coded data from said at least one code marking region.