Signal extraction circuit, signal extraction method, and distance measurement method and device
View Patent ↗A signal extraction circuit, a signal extraction method, and a distance measurement method and device. The distance measurement method comprises: performing multiple signal extractions using a circuit in a sensor, so as to obtain multiple extraction results; and determining the distance to a measurement object according to the multiple extraction results. Compared with pixel circuits in the prior art, the signal extraction circuit reduces the number of capacitors by half, thereby significantly increasing effective areas in pixels, and reducing calculation errors resulting from capacitance differences between the various capacitors. Moreover, part of the calculation is completed during the signal extraction, thus reducing the pressure of subsequent data processing, and particularly improving the accuracy and speed of distance measurement during the distance measurement process.
1 . A ranging method performed by using a signal extraction circuit, wherein the signal extraction circuit comprises an integrating unit, at least two charging branches connected with the integrating unit, a power supply, a first signal extraction module, a second signal extraction module, and a demodulation module configured to generate demodulation signals to respectively control the at least two charging branches to be turned on or turned off,
wherein the at least two charging branches comprise
a first charging branch in which a signal generating unit is connected with a first end of the integrating unit and a second end of the integrating unit is connected with the power supply, the signal generating unit is configured to convert a received external signal into an electrical signal, and
a second charging branch in which the signal generating unit is connected with the second end of the integrating unit and the first end of the integrating unit is connected with the power supply,
wherein an emission light signal emitted from a light source is reflected by a to-be-measured target to obtain an echo signal, and the emission light signal has a pulse width, the demodulation module generates a first demodulation signal, a second demodulation signal, a third demodulation signal and a fourth demodulation signal; and
wherein the ranging method comprises:
generating electrical charges by the signal generating unit based on a received background light signal having a preset duration and one part of the echo signal, and controlling the first charging branch of the first signal extraction module to be turned on by using the first demodulation signal so that the current electrical charges in the signal generating unit are transferred to the first end of the integrating unit in the first signal extraction module, wherein a first charge amount of the electrical charges are transferred at an end of the transfer;
generating electrical charges by the signal generating unit based on the received background light signal having the preset duration, and controlling the second charging branch of the first signal extraction module to be turned on by using the second demodulation signal so that the current electrical charges in the signal generating unit are transferred to the second end of the integrating unit in the first signal extraction module, wherein a second charge amount of the electrical charges are transferred at the end of the transfer;
obtaining a first signal extraction result by the integrating unit in the first signal extraction module based on the first charge amount and the second charge amount;
generating electrical charges by the signal generating unit based on the received background light signal having the preset duration and the other part of the echo signal, and controlling the first charging branch of the second signal extraction module to be turned on by using the third demodulation signal, so that the current electrical charges in the signal generating unit are transferred to the first end of the integrating unit in the second signal extraction module, wherein a third charge amount of the electrical charges are transferred at the end of the transfer;
generating electrical charges by the signal generating unit based on the received background light signal having preset duration, and controlling the second charging branch of the second signal extraction module to be turned on by using the fourth demodulation signal so that the current electrical charges in the signal generating unit are transferred to the second end of the integrating unit in the second signal extracting module, wherein a fourth charge amount of electrical charges are transferred at the end of the transfer;
obtaining a second signal extraction result by the integrating unit in the second signal extraction module based on the third charge amount and the fourth charge amount; and
calculating a distance between the light source and the to-be-measured target based on the first signal extraction result, the second signal extraction result and the pulse width.
2 . The ranging method according to claim 1 , wherein the signal generating unit is reset before receiving a signal each time, and the integrating unit is reset after obtaining the signal extraction result each time.
3 . The ranging method according to claim 1 , wherein a falling edge of the first demodulation signal is aligned with a rising edge of the third demodulation signal, and the second demodulation signal and the fourth demodulation signal do not overlap.