This document —     specifies two methodologies for the measurement of specific attributes of two-dimensional bar code symbols – one of which applies to multi-row bar code symbologies and the other to two-dimensional matrix symbologies; —     specifies methods for evaluating and grading these measurements and deriving an overall assessment of symbol quality; —     gives information on possible causes of deviation from optimum grades to assist users in taking appropriate corrective action. This document applies to two-dimensional symbologies for which a reference decode algorithm has been defined, however the methodologies in this document can be applied partially or wholly to other similar symbologies. NOTE            While this document can be applied to direct part marks, better correlation between measurement results and scanning performance can be obtained with ISO/IEC 29158 in combination with this document.