Method and system to increase dynamic range of time-of-flight (TOF) and/or imaging sensors

A method to enhance dynamic range of an array of photodetectors responsive to incoming optical energy returned from an object a distance Z away to determine at least distance Z to said object, said photodetectors having a dynamic range in dB of DR before application of the method, the method including:

• (a) controllably enabling said photodetectors to receive said incoming optical energy during n sequential unequal time duration sub-intervals;
• (b) at the end of each of said n unequal time duration sub-intervals storing a detection output signal from each of said photodetectors, where n>1 and wherein at least a pair of said unequal time duration sub-intervals, denoted shutteri and shutteri-1, satisfy a relationship
• 20
• ·
• log
• 10
• ⁢
• shutter
• i
• shutter
• i
• -
• 1
• ≤
• DR
• ;
• (c) determining a best quality one of n detection signals stored at step (b);
• and
• (d) repeating step (b) and step (c) as needed thereafter.

A CMOS-implementable system to enhance dynamic range of an array of photodetectors responsive to incoming optical energy returned from an object a distance Z away to determine at least distance Z to said object, said photodetectors having a dynamic range in dB of DR before enhancement of dynamic range, the system including:

• means for enabling said photodetectors to receive said incoming optical energy during a long time interval;
• means for storing, within said long time interval at the end of each of a number n of unequal time duration sub-intervals, a detection output signal from each of said photodetectors, where n>1, wherein at least a pair of said unequal time duration sub-intervals, denoted shutteri and shutteri-1, satisfy a relationship
• 20
• ·
• log
• 10
• ⁢
• shutter
• i
• shutter
• i
• -
• 1
• ≤
• DR
• and wherein adjacent said unequal time duration sub-intervals are separated from each other in a manner selected from a group consisting of (I) linearly, (ii) non-linearly, and (iii) logarithmically;
• means for determining a best quality one of n detection signals stored in said means for storing;
• and
• means for causing said means for storing and said means for determining to respectively store and determine as needed.

A CMOS-implementable system to enhance dynamic range of an array of photodetectors responsive to incoming optical energy returned from an object a distance Z away to determine at least distance Z to said object, said photodetectors having a dynamic range in dB of DR before enhancement of dynamic range, the system including:

• means for controllably enabling said photodetectors to receive said incoming optical energy during n sequential unequal time duration sub-intervals, wherein adjacent said unequal time duration sub-intervals are separated from each other in a manner selected from a group consisting of (i) linearly, (ii) non-linearly, and (iii) logarithmically;
• means for storing, at the end of each of said n unequal time duration sub-intervals, a detection output signal from each of said photodetectors, where n>1 and wherein at least a pair of said unequal time duration sub-intervals, denoted shutteri and shutteri-1, satisfy relationship
• 20
• ·
• log
• 10
• ⁢
• shutter
• i
• shutter
• i
• -
• 1
• ≤
• DR
• ;
• means for determining a best quality one of n detection signals stored in said means for storing;
• and
• means for selectively repeatedly enabling each of said photodetectors to receive said incoming optical energy for a time sub-interval associated with said best quality one of said n detection signals determined by said means for determining.