Object detection apparatus and method
First Claim
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1. A sensor system comprising:
- a first and second transmit signal chain for transmitting signals at respective first and second frequencies;
a first and second receive signal chain for receiving reflections of the signals transmitted by the corresponding first and second transmit signal chains; and
a signal processing unit for evaluating respective reflections received by the first and second receive signal chains to determine whether or not an object is composed of one type of material or of another type of material, the evaluation comprising a comparison of the reflections received by the first receive signal chain to the reflections received by the second received signal chain, which comparison is measured against a benchmark that indicates whether or not an object is of one type of material or another type of material;
wherein the first and second frequencies are selected such that the ratio of the amount of energy reflected at the first frequency to the amount of enegy reflected at the second frequency by the one type of material is significantly greater than the ratio of the amount of energy reflected at the first frequency to the amount of energy reflected at the second frequency by the other type of material.
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Abstract
In order to detect and classify objects in a relatively small obstruction-filled space (e.g. underneath a vehicle), a sensing method and apparatus incorporating the use of at least two carefully selected transmission frequencies is provided. In embodiments where the transmission frequencies are radio frequencies, the sensing apparatus can be considered and analysed as a short-range radar system. Alternatively, if the transmission frequencies are acoustic, the sensing apparatus can be considered and analysed as a sonar-based system.
24 Citations
27 Claims
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1. A sensor system comprising:
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a first and second transmit signal chain for transmitting signals at respective first and second frequencies;
a first and second receive signal chain for receiving reflections of the signals transmitted by the corresponding first and second transmit signal chains; and
a signal processing unit for evaluating respective reflections received by the first and second receive signal chains to determine whether or not an object is composed of one type of material or of another type of material, the evaluation comprising a comparison of the reflections received by the first receive signal chain to the reflections received by the second received signal chain, which comparison is measured against a benchmark that indicates whether or not an object is of one type of material or another type of material;
wherein the first and second frequencies are selected such that the ratio of the amount of energy reflected at the first frequency to the amount of enegy reflected at the second frequency by the one type of material is significantly greater than the ratio of the amount of energy reflected at the first frequency to the amount of energy reflected at the second frequency by the other type of material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of sensing comprising:
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i) transmitting signals on first and second frequencies;
ii) receiving reflections of the transmitted signals at the first and second frequencies;
iii) processing the received reflections of the transmitted signals to determine whether or not objects are present; and
iv) if objects are present, further processing the reflections to determine whether or not objects are of a certain type of material or not, wherein the processing of the respective received reflections at the first and second frequencies to determine whether or not objects are of the certain type of material or not includes comparing the reflections received at the first frequency to the reflections received at the second frequency and measuring the comparison against a benchmark to determine whether or not an object is of the certain type of material or not;
wherein the first and second frequencies are selected such that the ratio of the amount of energy reflected at the first frequency to the amount of energy reflected at the second frequency by the certain type of material is significantly greater than the ratio of the amount of energy reflected at the first frequency to the amount of energy reflected at the second frequency by other types of material. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification