Object detection apparatus, object detection method, and computer-readable recording medium

An object detection method, performed by an object detection apparatus, for detecting an object with radio waves, the object detection method comprising:

• emitting a radio wave as a transmission signal toward the object;
• receiving, through a plurality of receiving antennas, radio waves reflected by the object as reception signals, and generating, for each reception signal received by the respective plurality of receiving antennas, based on the reception signals, an intermediate frequency signal, wherein a reference receiving antenna and a measurement receiving antenna are used as the receiving antennas;
• deciding sampling times so as to suppress generation of a virtual image by a beam pattern obtained by synthesizing the respective intermediate frequency signals, and performing sampling on the intermediate frequency signals at the decided sampling times wherein the sampling is executed on a first intermediate frequency signal generated from a reception signal received by the measurement receiving antenna and a second intermediate frequency signal generated from a reception signal received by the reference receiving antenna, and
• based on obtained sample values, the intermediate frequency signal generated from the reception signal received by the measurement receiving antenna is normalized according to the intermediate frequency signal generated from the reception signal received by the reference receiving antenna, and a normalized intermediate frequency signal is generated as the intermediate frequency signal for position detection, and
• when the object is detected, an evaluation function that represents a position distribution of the object is calculated from the normalized intermediate frequency signal, and based on the evaluation function, the position and shape of the object are detected.

A non-transitory computer-readable recording medium including,

• in an object detection apparatus including a transmission unit configured to emit a radio wave as a transmission signal toward an object, a reception unit configured to receive, through a plurality of receiving antennas, radio waves reflected by the object as reception signals, and to generate, for each reception signal received by the respective plurality of receiving antennas, based on the reception signals, an intermediate frequency signal, and a computer, wherein the reception unit includes a reference receiving antenna and a measurement receiving antenna as the receiving antenna,
• a program recorded on the non-transitory computer-readable recording medium, the program including instructions that cause the computer to carry out:
• deciding sampling times so as to suppress generation of a virtual image by a beam pattern obtained by synthesizing the respective intermediate frequency signals, and performing sampling on the intermediate frequency signals at the decided sampling times wherein the sampling is executed on a first intermediate frequency signal generated from a reception signal received by the measurement receiving antenna and a second intermediate frequency signal generated from a reception signal received by the reference receiving antenna, and
• based on obtained sample values, the intermediate frequency signal generated from the reception signal received by the measurement receiving antenna is normalized according to the intermediate frequency signal generated from the reception signal received by the reference receiving antenna, and a normalized intermediate frequency signal is generated as the intermediate frequency signal for position detection, and
• when the object is detected, an evaluation function that represents a position distribution of the object is calculated from the normalized intermediate frequency signal, and based on the evaluation function, the position and shape of the object are detected.