Time-of-flight distance measuring system and calibration method

1. A time-of-flight distance measuring system, comprising:

a delay unit, receiving a plurality of delay signals and configured to generate a plurality of delayed pulses according to the plurality of delay signals, wherein the plurality of delay signals correspond to a plurality of delay times;

a light-emitting unit, coupled to the delay unit and configured to generate a plurality of delayed pulsed lights according to the plurality of delayed pulses;

a photosensitive pixel circuit, configured to receive a plurality of delayed reflected lights corresponding to the plurality of delayed pulsed lights to generate a plurality of pixel signals corresponding to the plurality of delay times;

a storage unit, configured to store a correspondence between the plurality of delay times and the plurality of pixel signals; and

a control unit, coupled to the delay unit and configured to generate the plurality of delay signals;

wherein the time-of-flight distance measuring system performs a time-of-flight distance measuring according to the correspondence between the plurality of delay times and the plurality of pixel signals.

2. The time-of-flight distance measuring system of claim 1 , wherein the control unit generates an optimal delay signal to the delay unit according to the correspondence between the plurality of delay times and the plurality of pixel signals, and the time-of-flight distance measuring system performs the time-of-flight distance measuring according to the optimal delay signal, wherein the optimal delay signal corresponds to an optimal delay time.

3. The time-of-flight distance measuring system of claim 2 , wherein the delay unit generates an optimal delayed pulse according to the optimal delay signal, the light-emitting unit generates an optimal delayed pulsed light according to the optimal delayed pulse, the photosensitive pixel circuit receives an optimal delayed reflected light corresponding to the optimal delayed pulsed light to generate an optimal delayed pixel signal, and the time-of-flight distance measuring system computes a time-of-flight distance corresponding to a target object according to the optimal delayed pixel signal.

4. The time-of-flight distance measuring system of claim 1 , wherein the plurality of delayed reflected lights are reflected from a reflector, wherein there is a fixed distance between the reflector and the time-of-flight distance measuring system.

5. The time-of-flight distance measuring system of claim 1 , wherein the photosensitive pixel circuit comprises:

a photosensitive device;

a first readout circuit, comprising a first transmission gate, wherein the first transmission gate is coupled to the photosensitive device, and the first transmission gate receives the first transmission signal and is conducted at a first conduction time; and

a second readout circuit, comprising a second transmission gate, wherein the second transmission gate is coupled to the photosensitive device, and the second transmission gate receives the second transmission signal and is conducted at a second conduction time, wherein the second readout circuit outputs the plurality of pixel signals;

wherein the first conduction time and the second conduction time are separated by a time interval.

6. A calibration method for a time-of-flight distance measuring system, the calibration method comprising:

generating a plurality of delay signals, wherein the plurality of delay signals correspond to a plurality of delay times;

generating a plurality of delayed pulses according to the plurality of delay signals;

emitting a plurality of delayed pulsed lights corresponding to the plurality of delayed pulses;

receiving a plurality of delayed reflected lights corresponding to the plurality of delayed pulsed lights to generate a plurality of pixel signals corresponding to the plurality of delay times;

storing a correspondence between the plurality of delay times and the plurality of pixel signals; and

performing a time-of-flight distance measuring according to the correspondence between the plurality of delay times and the plurality of pixel signals.

7. The calibration method of claim 6 , wherein the step of performing the time-of-flight distance measuring according to the correspondence between the plurality of delay times and the plurality of pixel signals comprises:

generating an optimal delay signal to a delay unit according to the correspondence between the plurality of delay times and the plurality of pixel signals, wherein the optimal delay signal corresponds to an optimal delay time; and

performing the time-of-flight distance measuring according to the optimal delay signal.

8. The calibration method of claim 7 , wherein the step of performing the time-of-flight distance measuring according to the optimal delay signal comprises:

generating an optimal delayed pulse according to the optimal delay signal;

generating an optimal delayed pulsed light according to the optimal delayed pulse;

receiving an optimal delayed reflected light corresponding to the optimal delayed pulsed light to generate the optimal delayed pixel signal; and

computing a time-of-flight distance corresponding to a target object according to the optimal delayed pixel signal.

9. The calibration method of claim 6 , wherein the plurality of delayed reflected lights are reflected from a reflector, wherein there is a fixed distance between the reflector and the time-of-flight distance measuring system.

10. A time-of-flight distance measuring method for a time-of-flight distance measuring system, the time-of-flight distance measuring method comprising:

obtaining a correspondence between a plurality of delay times and a plurality of pixel signals; and

performing a time-of-flight distance measuring according to the correspondence between the plurality of delay times and the plurality of pixel signals, wherein the correspondence between the plurality of delay times and the plurality of pixel signals is obtained through a time-of-flight calibration method and stored in the time-of-flight distance measuring system, and the time-of-flight calibration method comprises:

generating a plurality of delay signals, wherein the plurality of delay signals correspond to the plurality of delay times;

generating a plurality of delayed pulses according to the plurality of delay signals;

emitting a plurality of delayed pulsed lights corresponding to the plurality of delayed pulses;

receiving a plurality of delayed reflected lights corresponding to the plurality of delayed pulsed lights to generate the plurality of pixel signals corresponding to the plurality of delay times; and

outputting the correspondence between the plurality of delay times and the plurality of pixel signals.

11. The time-of-flight distance measuring method according to claim 10 , wherein the step of performing the time-of-flight distance measuring according to the correspondence between the plurality of delay times and the plurality of pixel signals comprises:

generating an optimal delay signal to a delay unit according to the correspondence between the plurality of delay times and the plurality of pixel signals, wherein the optimal delay signal corresponds to an optimal delay time; and

performing the time-of-flight distance measuring according to the optimal delay signal.

12. The time-of-flight distance measuring method according to claim 11 , wherein the step of performing the time-of-flight distance measuring according to the optimal delay signal comprises:

generating an optimal delayed pulse according to the optimal delay signal;

generating an optimal delayed pulsed light according to the optimal delayed pulse;

receiving an optimal delayed reflected light corresponding to the optimal delayed pulsed light to generate the optimal delayed pixel signal; and

computing a time-of-flight distance corresponding to a target object according to the optimal delayed pixel signal.

13. The time-of-flight distance measuring method according to claim 10 , wherein the plurality of delayed reflected lights are reflected from a reflector, wherein there is a fixed distance between the reflector and the time-of-flight distance measuring system.