Method and device for evaluating an object height using ultrasonic signals received by an ultrasonic sensor mounted on a vehicle

An ultrasonic sensor system for a vehicle, comprising:

• at least one ultrasonic sensor configured to emit ultrasonic signals and to acquire ultrasonic signals that are reflections by an object of the emitted ultrasonic signals;
• and
• a computing unit configured to evaluate an object height of the object using the ultrasonic signals acquired by the ultrasonic sensor, the computing unit configured to:
• in each measurement cycle:
• a. acquire a first ultrasonic signal as an edge reflection or as a directly traveling echo of an object;
• b. calculate an expectation window for an associated interior-corner reflection;
• c. acquire a second ultrasonic signal;
• d. when the second ultrasonic signal is acquired in the expectation window, identify the second ultrasonic signal as an interior-corner reflection associated with the first ultrasonic signal, and combine the first ultrasonic signal and the second ultrasonic signal to form a signal group;
• e. determine a first significance of the first ultrasonic signal and determine a second significance of the second ultrasonic signal, the significance of each acquired ultrasonic signal of the first and second ultrasonic signals indicating a probability that the acquired ultrasonic signal is a reflection of an emitted ultrasonic signal by at least one object;
• f. assign the signal group to an object in a surrounding environment of the vehicle;
• g. compare the first significance and the second significance and, as a function of the comparison, assigning the signal group to a first echo group or to a second echo group;
• determine a first rate of the assignment of a signal group to the first echo group over a determined number of measurement cycles;
• determine a second rate of the assignment of the signal group to the second echo group over the determined number of measurement cycles;
• evaluate the object height as a function of the first rate and the second rate.

A non-transitory computer-readable medium on which is stored a computer program including program code for evaluating an object height using ultrasonic signals acquired by an ultrasonic sensor mounted on a vehicle, the program code, when executed by a computer, causing the computer to perform the following steps:

• in each measurement cycle:
• a. acquiring a first ultrasonic signal as an edge reflection or as a directly traveling echo of an object;
• b. calculating an expectation window for an associated interior-corner reflection;
• c. acquiring a second ultrasonic signal;
• d. when the second ultrasonic signal is acquired in the expectation window, identifying the second ultrasonic signal as an interior-corner reflection associated with the first ultrasonic signal, and combining the first ultrasonic signal and the second ultrasonic signal to form a signal group;
• e. determining a first significance of the first ultrasonic signal and determining a second significance of the second ultrasonic signal, the significance of each acquired ultrasonic signal of the first and second ultrasonic signals indicating a probability that the acquired ultrasonic signal is a reflection of an emitted ultrasonic signal by at least one object;
• f. assigning the signal group to an object in a surrounding environment of the vehicle;
• g. comparing the first significance and the second significance and, as a function of the comparison, assigning the signal group to a first echo group or to a second echo group;
• determining a first rate of the assignment of a signal group to the first echo group over a determined number of measurement cycles;
• determining a second rate of the assignment of the signal group to the second echo group over the determined number of measurement cycles;
• evaluating the object height as a function of the first rate and the second rate.