Method and system for noise simulation analysis useable with systems including time-of-flight depth systems
View Patent ↗An analytical tool useable with complex systems receives as input various system parameters to predict whether sufficiently accurate quality depth data will be provided by the TOF system. Depth data quality estimates involve dividing system operation into smaller operations whose individual depth data quality contributions can be more readily computed. The effect of the individual operations is combined and the tool outputs a depth data quality estimate accounting for the net result of the various unique operations performed by the system. When used with a TOF system, input parameters may include magnitude and angular distribution of TOF emitted optical energy, desired signal/noise, sensor characteristics, TOF imaging optics, target object distances and locations, and magnitude of ambient light. Analytical tool output data can ensure adequate calculation accuracy to optimize the TOF system pre-mass production, even for TOF systems whose sequence of operations and sensor operations are flexibly programmable.
1. A processor implemented method to estimate signal to noise (S/N) of an electrical system that has a sequence of operations Oi, each of said operations Oi combining a signal and statistical noise from prior operations in said sequence with signal and statistical noise at a current operation in said sequence of operations Oi, the method including the following steps:
(a) at each sequence in said operations Oi, combining effects of each independent statistical noise source independently of other independent statistical noise sources such that each independent statistical noise source is self-correlating;
(b) combining final noise contribution of each independent statistical noise source at an output of said system to yield a final statistical noise estimate for said system;
wherein said final statistical noise estimate resulting from step (b) is more accurate than if statistical noise models for independent noise sources at each sequence in operations Oi were combined using RMS values.
2. The processor implemented method of claim 1 , wherein step (b) yields signal and noise estimates exceeding accuracy of a closed form expression of noise following operation Oi.
3. The processor implemented method of claim 1 , wherein accumulated noises are derived from at least one noise component selected from a group consisting of (i) shot noise, (ii) KT/C noise, (iii) flicker noise, (iv) ADC quantization noise, (v) digital accumulation noise, and (vii) thermal noise.
4. The processor implemented method of claim 1 , further including accumulating at least one value of at least one of signal and noise, before carrying out step Oi.
5. The processor implemented method of claim 1 , wherein step (a) is carried out using at least one of (i) hardware and (ii) software.
6. The processor implemented method of claim 1 , wherein step (b) is carried out using at least one of (i) hardware and (ii) software.
7. The processor implemented method of step 1 , wherein at step (a) each said independent statistical noise source is modeled as being self-correlating such that computation is carried out absent recourse to use of absolute RMS magnitudes.
8. The processor implemented method of step 1 , wherein said electrical system includes at least one of (i) an imaging system, (ii) a depth system, and (iii) a time-of-flight depth system.
9. A sub-system to estimate signal to noise (S/N) of an electrical system that has a sequence of operations Oi, each of said operations Oi to combine a signal and statistical noise from prior operations in said sequence with signal and statistical noise at a current operation in said sequence of operations Oi, the sub-system including:
a processor; and
a memory including code to instruct the processor to compute effects, at each sequence in said operations Oi, of each independent statistical noise source independently of other independent statistical noise sources such that each independent statistical noise source is self-correlating;
to combine final noise contribution of each independent statistical noise source at an output of said system to yield a final statistical noise estimate for said system;
wherein said final statistical noise estimate yielded by said combining is more accurate than if statistical noise models for independent noise sources at each sequence in operations Oi were computed.
10. The sub-system of claim 9 , wherein said combining yields signal and noise estimates exceeding accuracy of a closed form expression of noise following operation Oi.
11. The sub-system of claim 9 , wherein accumulated noises are derived from at least one noise component selected from a group consisting of (i) shot noise, (ii) KT/C noise, (iii) flicker noise, (iv) ADC quantization noise, (v) digital accumulation noise, and (vii) thermal noise.
12. The sub-system of claim 9 , further including code instructing the processor to accumulate at least one value of at least one of signal and noise, before carrying out step Oi.
13. The sub-system of claim 9 , wherein said code includes instructions to model each said independent statistical noise source as being self-correlating such that computation is carried out absent recourse to use of absolute RMS magnitudes.
14. The sub-system of claim 9 , wherein said electrical system includes at least one of (i) an imaging system, (ii) a depth system, and (iii) a time-of-flight depth system.