Information detection method and system

An information detection system, comprising:

• a first light source, a second light source, a frequency shifter, a delay component, a transceiving module, and a processing module, wherein
• the first light source is configured to generate a first optical signal and divide the first optical signal into a first measurement optical signal and a first reference optical signal, and the second light source is configured to generate a second optical signal and divide the second optical signal into a second measurement optical signal and a second reference optical signal;
• the delay component is configured to perform delay processing on the first measurement optical signal to obtain a delayed first measurement optical signal;
• the frequency shifter is configured to shift a frequency of the second measurement optical signal by a specified frequency offset to obtain a frequency-shifted second measurement optical signal;
• the transceiving module is configured to combine the delayed first measurement optical signal and the frequency-shifted second measurement optical signal into a detection optical signal, transmit the detection optical signal into a detection space and receive an echo signal;
• the processing module is configured to combine the first reference optical signal and the second reference optical signal into a reference optical signal, and perform frequency beating on the reference optical signal and the echo signal to obtain a beat frequency signal;
• determine velocity information of a detected target based on a first frequency point located in a velocity frequency interval among two frequency points resolved from the beat frequency signal, and determine distance information of the detected target based on a second frequency point located in a distance frequency interval among the two frequency points, wherein the velocity frequency interval is symmetrical with respect to a frequency point for the specified frequency offset, and the velocity frequency interval and the distance frequency interval do not overlap.