Optical distance measurement device
A sensing device comprises a transmitter and a receiver. The transmitter repetitively emits a modulated electro-magnetic signal and the emitted signal interacts with an object producing a counter propagating return signal. The return signal is detected and converted into digital signals by the receiver via a reception channel through the use of edge transitions rather than logic levels from one or more comparator outputs to reconstruct the return signal waveform. Waveform acquisition and reconstruction are based on edge sampling. Methods of providing optical feedback using a moving waveguide in time-of-flight distance measurements are also disclosed.
1. A method comprising:
repetitively transmitting, using a transmitter, one more modulated electromagnetic signals;
producing, using a receiver, a single-bit quantized digital signal from a received analog signal associated with the one or more modulated electromagnetic signals based on a swept detection reference that is passed through an extent of a signal envelope;
detecting, using the receiver, rising and falling edges of the single-bit quantized digital signal;
generating, using the receiver, a histogram of the rising and falling edges of the single-bit quantized digital signal;
determining, using the receiver, a slope component based on the histogram; and
constructing, using the receiver, a signal waveform from the integral of the slope component.
2. The method of claim 1 , estimating the extent of the signal waveform based on a sum of the rising and falling edges of the single-bit quantized digital signal.
3. The method of claim 2 , further comprising estimating, using the receiver, the slope component using a linearizing function based on a normalization of a difference of edge counts.
4. The method of claim 1 , wherein the extent of the signal waveform is estimated based on a number of signal counts above a threshold using a shaped transmit pulse.
5. The method of claim 1 , wherein the signal waveform is constructed from the integral of the slope component and the swept reference.
6. An apparatus, comprising:
a transmitter configured to repetitively emit one more modulated electromagnetic signals;
a receiver configured to:
receive portions of the one or more modulated electromagnetic signals,
detect rising and falling edges of the received portions with respect to a swept reference to produce a single-bit quantized digital signal corresponding to the received portions;
generate a histogram of rising and falling edges in the single bit quantized digital signal,
determine slope components for the received portions based on the histogram, and
construct a received signal waveform based on an integral of the slope components.
7. The apparatus of claim 6 , wherein the receiver is configured to vary the swept reference as the signal portions are detected.
8. The apparatus of claim 7 , wherein the receiver is configured to estimate a total signal amplitude based on a sum of the detected rising and falling edges.
9. The apparatus of claim 8 , wherein the receiver is configured to estimate the slope components using a linearizing function based on a normalization of a difference of edge counts.
10. The apparatus of claim 7 , wherein the receiver is configured to estimate a total signal amplitude based on a number of signal counts above a threshold and a shaped transmit pulse.