System and method for dynamic gain switching in detecting objects behind an opaque surface

1 . A scanner for dynamic gain switching in detecting one or more objects behind an opaque surface, comprising:

a pair of capacitive sensors, controlled by one or more processors, configured to collect sensor data of the one or more objects behind an opaque surface along a scan path of the scanner;

the one or more processors are configured to monitor characteristics of signal strengths detected by the pair of capacitive sensors using the sensor data, wherein the characteristics of signal strengths include a saturation condition detected in a first capacitive sensor or in a second capacitive sensor in the pair of capacitive sensors;

the one or more processors are further configured to switch gain sensitivity of the pair of capacitive sensors dynamically from a first gain sensitivity mode to a second gain sensitivity mode, in response to the saturation condition being met;

the pair of sensors are further configured to continue to collect, using the second gain sensitivity mode, sensor data of the one or more objects behind the opaque surface along the scan path of the scanner; and

the one or more processors are further configured to inform a user, via a user interface of the scanner, information derived from the sensor data collected about the one or more objects behind the opaque surface.

2 . The scanner of claim 1 , wherein the saturation condition comprises:

signal strength detected by a metal sensor increases, and the signal strength detected by the metal sensor is larger than a predetermined metal gain switch threshold.

3 . The scanner of claim 2 , wherein the saturation condition further comprises:

an absolute difference of signal strength detected by the first capacitive sensor and by the second capacitive sensor in the pair of capacitive sensors is larger than a predetermined high absolute difference threshold.

4 . The scanner of claim 1 , wherein the saturation condition further comprises:

signal strength detected by the first capacitive sensor increases and by the second capacitive sensor increases; and

signal strength of the first capacitive sensor or the second capacitive sensor is larger than a predetermined high gain sensitivity threshold.

5 . The scanner of claim 1 , wherein the one or more processors are further configured to:

calibrate the pair of capacitive sensors dynamically to collect sensor data in the second gain sensitivity mode.

6 . The method of claim 5 , wherein the one or more processors are further configured to:

set gain sensitivity value for the pair of capacitive sensors in accordance with the second gain sensitivity mode;

set a baseline minimum signal strength for collecting sensor data in the second gain sensitivity mode; and

convert collected raw sensor data to normalized sensor data in accordance with the baseline minimum signal strength.

7 . The scanner of claim 1 , wherein the one or more processors are further configured to:

switch from the second gain sensitivity mode to the first gain sensitivity mode in response to the signal strength detected by the first capacitive sensor decreases and the signal strength detected by the second capacitive sensor decreases, and the signal strength of the first capacitive sensor or the signal strength of the second capacitive sensor falls below a predetermined low signal threshold.

8 . The scanner of claim 7 , wherein the one or more processors are further configured to:

calibrate the pair of capacitive sensors of the scanner to collect sensor data in the first gain sensitivity mode.

9 . The scanner of claim 8 , wherein the one or more processors are further configured to:

continue to collect, by the pair of capacitive sensors using the first gain sensitivity mode, sensor data of the one or more objects behind the opaque surface.

10 . The scanner of claim 8 , wherein the one or more processors are further configured to:

set gain sensitivity value for the pair of capacitive sensors in accordance with the first gain sensitivity mode;

set a first baseline minimum signal strength for collecting sensor data in the first gain sensitivity mode; and

convert collected raw sensor data to normalized sensor data in accordance with the first baseline minimum signal strength.

11 . A method for dynamic gain switching in detecting one or more objects behind an opaque surface, comprising:

collecting, by a pair of capacitive sensors and a metal sensor of a scanner, sensor data of the one or more objects behind an opaque surface;

monitoring, by one or more processors of the scanner, characteristics of signal strengths detected by the pair of capacitive sensors and the metal sensor using the sensor data, wherein characteristics of signal strengths include a saturation condition detected by the pair of capacitive sensors and the metal sensor;

switching, by the one or more processors, gain sensitivity of the pair of capacitive sensors dynamically from a first gain sensitivity mode to a second gain sensitivity mode, in response to the saturation condition being met;

continue collecting, by the pair of capacitive sensors using the second gain sensitivity mode, sensor data of the one or more objects behind the opaque surface; and

informing a user, by the one or more processors via a user interface of the scanner, information derived from the sensor data collected about the one or more objects behind the opaque surface.

12 . The method of claim 11 , wherein the saturation condition comprises:

signal strength detected by a metal sensor increases, and the signal strength detected by the metal sensor is larger than a predetermined metal gain switch threshold.

13 . The method of claim 12 , wherein the saturation condition further comprises:

an absolute difference of signal strength detected by the first capacitive sensor and by the second capacitive sensor in the pair of capacitive sensors is larger than a predetermined high absolute difference threshold.

14 . The method of claim 11 , wherein the saturation condition further comprises:

signal strength detected by the first capacitive sensor increases and by the second capacitive sensor increases; and

signal strength of the first capacitive sensor or the second capacitive sensor is larger than a predetermined high gain sensitivity threshold.

15 . The method of claim 11 , wherein switching gain sensitivity of the pair of capacitive sensors from the first gain sensitivity mode to the second gain sensitivity mode further comprises:

calibrating the pair of capacitive sensors dynamically to collect sensor data in the second gain sensitivity mode.

16 . The method of claim 15 , further comprises:

setting gain sensitivity value for the pair of capacitive sensors in accordance with the second gain sensitivity mode;

setting a baseline minimum signal strength for collecting sensor data in the second gain sensitivity mode; and

converting collected raw sensor data to normalized sensor data in accordance with the baseline minimum signal strength.

17 . The method of claim 11 , further comprises:

switching from the second gain sensitivity mode to the first gain sensitivity mode in response to the signal strength detected by the first capacitive sensor decreases and the signal strength detected by the second capacitive sensor decreases, and the signal strength of the first capacitive sensor or the signal strength of the second capacitive sensor falls below a predetermined low signal threshold.

18 . The method of claim 17 , further comprises:

calibrating the pair of capacitive sensors of the scanner to collect sensor data in the first gain sensitivity mode.

19 . The method of claim 18 , further comprises:

continue collecting, by the pair of capacitive sensors using the first gain sensitivity mode, sensor data of the one or more objects behind the opaque surface.

20 . The method of claim 18 , further comprises:

setting gain sensitivity value for the pair of capacitive sensors in accordance with the first gain sensitivity mode;

setting a first baseline minimum signal strength for collecting sensor data in the first gain sensitivity mode; and

converting collected raw sensor data to normalized sensor data in accordance with the first baseline minimum signal strength.