Some Imatest calculations up to v5.1 inappropriately averaged zeros with summary metrics

Problem

Certain imatest calculations in version 5.1 and below produced zeros when the calculation was not determined. These zero values could be inappropriately averaged with summary metrics which lead to these summary metrics being underreported.

The problem includes, but is not limited to the following summary metrics:

• Chromatic Aberration (CA) summary calculations CA_areaPCT_summary, CA_crossingPCT_summary, CA_R_G_PCT_summary, CA_B_G_PCT_summary where the individual outputs in CA_area_Pct_corner, CA_cross_Pct_corner, CA_crossing_R_G_PCT_corner, CA_crossing_B_G_PCT_corner, CA_crossing_R_G_Pxls, CA_crossing_B_G_Pxls, include zeros.
• MTF Summary metrics where higher frequency MTF values that are not achieved, and incorrectly reported as zero (corrected in v5.1.28)

Solution

• Take care not to use any summary metrics where the calculations output zeros
• Upgrade to Imatest 5.2 where these indeterminate calculations are reported as NaN (Not a Number), and will not be included in any averages