Calibration block for phased array of ultra-sonic elements

A calibration block for a phased array ultrasonic sensor, comprising:

• an engagement surface having a selected vertical extent along a vertical axis, and a selected horizontal extent along a horizontal axis;
• a block depth trajectory comprising a variable depth of the calibration block along the vertical axis, the depth of the calibration block at each position along the vertical axis comprising an effective distance between the engagement surface and an opposing surface, wherein the block depth trajectory comprises a plurality of steps having distinct depths;
• an end face defining at least one vertical feature hole;
• and
• a side face defining at least one horizontal feature hole.

A calibration block for a phased array ultrasonic sensor, comprising:

• an engagement surface having a selected vertical extent along a vertical axis, and a selected horizontal extent along a horizontal axis;
• a block depth trajectory comprising a variable depth of the calibration block along the vertical axis, the depth of the calibration block at each position along the vertical axis comprising an effective distance between the engagement surface and an opposing surface,
• wherein the block depth trajectory comprises at least two depth progression regimes, each one of the depth progression regimes comprising at least one of:
• a full thickness regime;
• a thickness progression regime;
• a minimum thickness regime;
• or
• a curved progression regime;
• an end face defining at least one vertical feature hole;
• and
• a side face defining at least one horizontal feature hole.