A magnetic sensor is provided with first and second magnetoresistive effect elements that can detect an external magnetic field. The first and second magnetoresistive effect elements include at least magnetization direction change layers where a direction of magnetization is changed according to an external magnetic field. The width W1 of a magnetization direction change layer in an initial magnetization direction of the magnetization direction change layer of the first magnetoresistive effect element, and the width W2 of a magnetization direction change layer in an initial magnetization direction of the magnetization direction change layer of the second magnetoresistive effect element have a relationship shown by formula (1) below. Sensitivity of the first magnetoresistive effect element to the external magnetic field is higher than that of the second magnetoresistive effect element.
W1>W2  (1)

A variety of magnetic field sensor arrangements provide so-called “tooth detectors” using a simple low-cost magnet.

A radio frequency (RF) imaging device comprises an optical position sensor, an RF sensor assembly, a processor, and a memory. The optical position sensor captures an optical image of a field of view and outputs data representing the optical image. The RF sensor assembly is disposed at a first position and receives an RF signal for capturing an RF image of a portion of a space disposed behind a surface at the first position and outputs data representing the RF signal. The processor receives the data representing the optical image and the RF signal, and determines that an optical signature of a reference marker is present in the optical image. If the optical signature is present in the optical image, the processor defines the first position of the RF assembly as a reference position. The memory stores the data representing the RF signal in association with the reference position.

A radio frequency (RF) imaging device comprises an optical position sensor, an RF sensor assembly, a processor, and a memory. The optical position sensor captures an optical image of a field of view and outputs data representing the optical image. The RF sensor assembly is disposed at a first position and receives an RF signal for capturing an RF image of a portion of a space disposed behind a surface at the first position and outputs data representing the RF signal. The processor receives the data representing the optical image and the RF signal, and determines that an optical signature of a reference marker is present in the optical image. If the optical signature is present in the optical image, the processor defines the first position of the RF assembly as a reference position. The memory stores the data representing the RF signal in association with the reference position.

A radio frequency (RF) imaging device comprises a position sensor, an RF sensor assembly, an optical sensor, a processor, and a memory. The position sensor determines a position of the RF imaging device relative to a surface. The RF sensor assembly captures RF image data representing an RF image of a portion of a space behind the surface at the determined position. The optical sensor captures optical image data representing an optical image of the surface at the determined position. The processor produces a composite image in which at least one or more portions of the RF image and one or more portions of the optical image that correspond to the same position relative to the surface are simultaneously viewable. The RF image data and the optical image data are stored in the memory in association with position data derived from the determined position of the RF imaging device.

A radio frequency (RF) imaging device comprises a position sensor, an RF sensor assembly, an optical sensor, a processor, and a memory. The position sensor determines a position of the RF imaging device relative to a surface. The RF sensor assembly captures RF image data representing an RF image of a portion of a space behind the surface at the determined position. The optical sensor captures optical image data representing an optical image of the surface at the determined position. The processor produces a composite image in which at least one or more portions of the RF image and one or more portions of the optical image that correspond to the same position relative to the surface are simultaneously viewable. The RF image data and the optical image data are stored in the memory in association with position data derived from the determined position of the RF imaging device.

The present invention generally relates to proximity sensor monitors and proximity monitor systems incorporating proximity sensor monitors. A proximity sensor monitor measures the impedance or other electrical characteristics of a proximity sensor component to determine the presence of a target. The proximity sensor monitor performs this measurement independently of a separate proximity sensor. The proximity sensor monitor is configured to compensate for differences between the measurement frequency of the proximity sensor monitor and the driving frequency of the proximity sensor.

The present invention generally relates to proximity sensor monitors and proximity monitor systems incorporating proximity sensor monitors. A proximity sensor monitor measures the impedance or other electrical characteristics of a proximity sensor component to determine the presence of a target. The proximity sensor monitor performs this measurement independently of a separate proximity sensor. The proximity sensor monitor is configured to compensate for differences between the measurement frequency of the proximity sensor monitor and the driving frequency of the proximity sensor.

A magnetic resonance technology is used to implement front and back proximity sensing capability for wireless devices such as a laptap device. For example, a high quality (Q) factor coil antenna may be embedded in a display, such as a liquid crystal display, of a first laptap device to detect other wireless devices (e.g., a second laptap) that are within coupling distance of the first laptap device. In this example, the second laptap device induces a sine wave signal to the first laptap device if the second laptap device is physically located at backside of the first laptap device. Otherwise, the second laptap device may induce a cosine wave signal to the first laptap device if the second laptap device is physically located at the front side of the first laptap device.

A magnetic resonance technology is used to implement front and back proximity sensing capability for wireless devices such as a laptap device. For example, a high quality (Q) factor coil antenna may be embedded in a display, such as a liquid crystal display, of a first laptap device to detect other wireless devices (e.g., a second laptap) that are within coupling distance of the first laptap device. In this example, the second laptap device induces a sine wave signal to the first laptap device if the second laptap device is physically located at backside of the first laptap device. Otherwise, the second laptap device may induce a cosine wave signal to the first laptap device if the second laptap device is physically located at the front side of the first laptap device.