Object detection device
View Patent ↗A device for detecting the presence of an object is provided. The device includes a light source, a current controller coupled to the light source, a sensor and a pattern detection engine. The current controller sets to provide the light source with a drive current having a pattern. The sensor is operable to receive light, notably light reflected from an object at the detection area and subsequently generates a signal in response to the light received. The pattern detection engine receives the signal from the sensor and subsequently reports the presence of the object upon determining the presence of the pattern in the signal. The object detection system is further configured to provide a navigation operation when an object is detected at the detection area.
1. An object detection device comprising:
a current controller operable to generate a drive current having a pattern;
a light source operable to emit light in response to the drive current;
a detection area configured to be illuminated by the light source;
a sensor array configured to receive the emitted light reflected from an object at the detection area and generate signals in response to the light received;
a shutter value generator configured to generate shutter values from the signals;
a shutter recorder to record the shutter values;
a pattern detection engine configured to receive the shutter values from the shutter recorder and operable to report the presence of the object upon determining the presence of the pattern in the shutter values; and
a navigation engine configured to provide a navigation operation in response to the signals from the sensor array.
2. The device of claim 1 , wherein the pattern detection engine is operable to report the presence of the object upon determining the presence of the pattern in the signal within a predetermined tolerance.
3. The device of claim 2 , wherein the navigation engine is configured to provide the navigation operation when an object is reported presence on the device.
4. The device of claim 1 , wherein the pattern is alternating high and low intensities having a known timing.
5. The device of claim 4 , wherein the pattern detection engine is configured to report the object being present upon determining the shutter values indicate at least one of (a) a high signal intensity at a timing corresponding to a high intensity emission of the light source and (b) low signal intensity at a timings corresponding to a low intensity emission of the light source.
6. The device of claim 4 , wherein the pattern detection engine further comprises:
a calculator operable to calculate,
(a) a first ratio as the ratio of high to low intensities of the drive current,
(b) a second ratio as the ratio of high to low signal intensities, wherein the second ratio is calculated from the shutter values, and
(c) a transmission-detection ratio as the ratio of the first ratio to the second ratio; and
a presence indicator operable to report the presence of the object upon determining the transmission-detection ratio is effectively equal to one.
7. The device of claim 4 , wherein the pattern detection engine further comprises:
a calculator operable to calculate a second ratio as the ratio of high to low signal intensities, wherein the second ratio is calculated from the shutter values; and
a presence indicator operable to report the lack of presence of the object upon determining the second ratio is effectively equal to one.
8. The device of claim 1 , wherein the device is a switch operable to switch on or off an appliance upon the pattern detection engine reporting a change in the presence or absence of the object.
9. The device of claim 1 , wherein device is portion of a power saving system operable to regulate the power consumption of an appliance.
10. An object detection method comprising:
generating a drive current having a pattern;
providing the drive current to a light source;
receiving a light reflected from an object at a detection area;
generating signals in response to the light received;
generating shutter values from the signals;
determining that the pattern is present in the shutter values; and
reporting the presence of the object;
providing navigation signals for a navigation operation in accordance with the light received.
11. The method of claim 10 , further comprising providing the light source with an alternating high and low current with a known timing.
12. The method of claim 10 , wherein the step of determining the pattern is present in the shutter values further comprises determining the pattern is present in the shutter values within a previously determined tolerance.
13. The method of claim 12 , wherein the step of determining the pattern is present in the shutter values further comprises:
calculating a first ratio as the ratio of high to low intensities of the drive current, calculating, from the shutter values, a second ratio as the ratio of high to low signal intensities, and calculating a transmission-detection ratio as the ratio of the first ratio to the second ratio; and
determining the pattern is present in the signal upon determining the transmission-detection ratio is effectively equal to one.
14. The method of claim 10 , wherein the step of determining the pattern is present in the shutter values further comprises:
calculating, from the shutter values, a ratio as the ratio of high to low signal intensities, and determining the pattern is present in the signal upon determining the transmission-detection ratio is effectively not equal to one.
15. The method of claim 10 , further comprising translating a number of gestures made by the object on the detection area to a navigation operation.
16. An optical finger navigation device, comprising:
a light source operable for emitting light having a pattern;
a sensor array configured to receive the emitted light reflected from a finger at a detection area and to generate signals in response to the light received;
a shutter value generator configured to generate shutter values from the signals;
a shutter value recorder configured to record the shutter values;
a pattern detection engine configured to receive the shutter values from the shutter value recorder and operable to report the presence of the finger upon determining the presence of the pattern in the shutter values; and
a navigation engine configured to provide a navigation operation in response to the signals.
17. The device of claim 16 , wherein the navigation engine is configured to provide the navigation operation when the object is reported present on the optical finger navigation device.