In the manual testing process, it would create the false detection and undetected defects because the human vision often has a certain bias due to inherent defects in humans.

在人工检测的过程当中，由于人本身存在的缺陷，其视觉往往会存在一定的偏差，这就会造成疵点的误检和漏检。

youdao

The sensitivity indicates detection in humans up to three years earlier than a mammogram can.

FORBES: Breast Exams: Mammography Is Not The Only Game In Town