A method and system dynamically calculates confidence levels associated
with accuracy of Z depth information obtained by a phase-shift
time-of-flight (TOF) system that acquires consecutive images during an
image frame. Knowledge of photodetector response to maximum and minimum
detectable signals in active brightness and total brightness conditions
is known a priori and stored. During system operation brightness
threshold filtering and comparing with the a priori data permits
identifying those photodetectors whose current output signals are of
questionable confidence. A confidence map is dynamically generated and
used to advise a user of the system that low confidence data is currently
being generated. Parameter(s) other than brightness may also or instead
be used.