Method and apparatus for object detection and ranging

• US 20040164852A1
• Filed: 02/23/2004
• Published: 08/26/2004
• Est. Priority Date: 05/28/2002
• Status: Active Grant

• Current Assignee: Coligen Corp.
• Original Assignee: Shih-Hsiung Li
• Inventors: Li, Shih-Hsiung
• Granted Patent: US 6,940,398 B2
• Time in Patent Office: Days
• US Class Current: 340/435
• CPC Class Codes: B60Q 9/006 using a distance sensor
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/9317 Driving backwards

Abstract

A method and apparatus for object detection and ranging is disclosed. An returned signal is sequentially received by one of several sensors mounted on a host vehicle. Each one in turn initiates successive sampling to collect a series of returned signal values, which are then compared with corresponding threshold values previously saved in a memory device to determine whether any object is in the way of the vehicle backing up and also to estimate the relative distance from the object. The control circuit in accordance with the invention includes a processor, which together with a channel selector establishes a sequence of signal transmission and reception each time by one of several sensors. A sampled signal is first passed through an A/D converter to become digital, and then it is input to the processor for object detection and ranging computation.

Claims

1. A method for detecting objects and ranging used by vehicle backing system, which includes:

presetting “

n”

number of threshold values in memory, each based on a specific distance;

sampling “

n”

times on an echoed signal;

saving “

n”

number of sampled signal values in memory;

comparing each sampled signal with the respective threshold value, if the value of the newly sampled data is greater, that means an object is present in the detection range, so distance computation can be initiated; and

the current sample value is further compared with the control data (i.e. previous sample value);

if the current sample value is not equal to the previous sample value, then the current sample data is saved to replace the previous control data;

but if two are equal or close to each other, the current sample value is only used for distance computation without updating the control data.

2. A method for detecting objects and ranging used by vehicle backing system as claimed in claim 1, whereby when any sampled signal is notably above the corresponding threshold value, that means an object is present, distance computation can be initiated, since the threshold value represents a predetermined distance value.

3. A method for detecting objects and ranging used by vehicle backing system as claimed in claim 1, whereby when one of the sampled data is notably above the previous sample, that means an object is present, distance computation can be initiated.

4. An apparatus for detecting objects and ranging used by vehicle backing system as claimed in claim 2, wherein the sensor array is made up of one or more signal sensors or transceivers.

5. An apparatus for detecting objects and ranging used by vehicle backing system as claimed in claim 3, wherein the sensor array comprises one or more signal sensors or transceivers.

6. A method for detecting objects and ranging used by vehicle backing system as claimed in claim 4, whereby, if one or more object is detected, the sensor recording the smallest distance value is regarded as the actual distance from the nearest object.

7. A method for detecting objects and ranging used by vehicle backing system as claimed in claim 5, whereby, if one or more object is detected, the alarm warning is issued with a frequency set to correspond to the relative distance.

8. A method for detecting objects and ranging used by vehicle backing system as claimed in claim 6, wherein, if an object is detected, the alarm warning is issued with a frequency set to correspond to the relative distance.

9. An apparatus for object detection and ranging used by vehicle backing system, which includes:

a processor, which is connected to an alarm and a memory device, and is used for detecting objects and issuing a warning when there is obstruction;

a channel selector, which is controlled by the processor and is used to select the active sensor;

multiple power boosters, which are connected between the channel selector and the sensors in the sensor array for controlling the signal transmission by the above sensors; and

an A/D converter, which is connected between the channel selector and the processor, and is used to convert the received signal to a digital format for computation of relative distance;

whereby, the processor through the channel selector governs the sequence of transmission of a ranging signal by one of the sensors in accordance with a given sequence, and later the reception of echoed signals, by the same sequence, which are then converted by the A/D converter to a digital format for computation of relative distance.

10. An apparatus for object detection and ranging used by vehicle backing system as claimed in claim 9, wherein the A/D converter is connected through a signal amplifier to the channel selector, and then further connected to the sensor array;

whereby the signal received from the sensor array is amplified and passed to the comparator in the A/D converter circuit.

11. An apparatus for object detection and ranging used by vehicle backing system as claimed in claim 9, wherein a latch is used to connect the I/O pins of the processor and the address pins of the memory device.

12. An apparatus for object detection and ranging used by vehicle backing system as claimed in claim 9, wherein the A/D converter includes:

a voltage doubling circuit whose inputs are respectively connected to the processor; and

a comparator where one input is connected to the output of the signal amplifier, the other input is connected to the output of the voltage doubling circuit, and the output is connected to the processor.

13. An apparatus for object detection and ranging used by vehicle backing system as claimed in claim 12, wherein the signal amplifier is formed from multiple cascaded operational amplifiers.

14. An apparatus for object detection and ranging used by vehicle backing system as claimed in claim 13, wherein the output from the first-stage operational amplifier in the signal amplification circuit is connected in series with a noise shielding circuit.

15. An apparatus for object detection and ranging used by vehicle backing system as claimed in claim 9, wherein the alarm is implemented by a buzzer.