Abstract: According to one embodiment, a structure evaluation system according to an embodiment includes a plurality of sensors, a position locator, and an evaluator. The plurality of sensors detect elastic waves. The position locator locates positions of elastic wave sources by using the elastic waves among the plurality of elastic waves respectively detected by the plurality of sensors having an amplitude exceeding a threshold value determined according to positions of the sources of the plurality of elastic waves and the positions of the plurality of disposed sensors. The evaluator evaluates a deteriorated state of the structure on the basis of results of the position locating of the elastic wave sources which is performed by the position locator.

Abstract: According to an embodiment, a structure evaluation system includes a plurality of sensors, a position locator, a velocity calculator, and an evaluator. The sensors detect an elastic wave generated from a structure. The position locator derives a wave source distribution of the elastic waves generated from the structure, on the basis of the elastic waves. The velocity calculator derives a propagation velocity of the elastic wave generated from the structure, on the basis of the elastic waves. The evaluator evaluates the soundness of the structure on the basis of the wave source distribution and the propagation velocity of the elastic waves.

Abstract: According to an embodiment, a structure evaluation system includes a plurality of sensors, a position locator, a velocity calculator, and an evaluator. The sensors detect an elastic wave generated from a structure. The position locator derives a wave source distribution of the elastic waves generated from the structure, on the basis of the elastic waves. The velocity calculator derives a propagation velocity of the elastic wave generated from the structure, on the basis of the elastic waves. The evaluator evaluates the soundness of the structure on the basis of the wave source distribution and the propagation velocity of the elastic waves.

Abstract: According to an embodiment, a detection device is used for a structure. The structure includes: a first member; a second member provided on an opposite side of the first member; and a welded portion that is provided along an end of the second member facing the first member and fixes the first member and the second member. The detection device include: a plurality of acoustic emission sensors that are disposed so as to be spaced apart from each other in a direction in which the welded portion extends and are configured to detect an elastic wave transmitted to the second member, each acoustic emission sensor being attached to the second member; and an outputter that outputs information, obtained from outputs of the plurality of the acoustic emission sensors.

Abstract: According to an embodiment, a structure evaluation system includes a plurality of sensors, a position locator, and an evaluator. The sensors detect an elastic wave generated from a structure. The position locator derives a source distribution of the elastic waves generated from the structure, caused by an impact on the structure. The evaluator evaluates a state of deterioration of the structure from characteristic parameters of the elastic waves in the source distribution.

Abstract: According to an embodiment, a structure evaluation system includes a plurality of AE sensors, a signal processor, a position locator, a velocity calculator, and an evaluator. The AE sensors detect an elastic wave generated from a structure. The signal processor extracts an AE signal including information on the elastic wave by performing signal processing on the elastic wave detected by the AE sensor. The position locator derives a wave source distribution indicating a distribution of sources of the elastic waves generated in the structure on the basis of the AE signals. The velocity calculator derives a propagation velocity of the elastic wave generated in the structure on the basis of the AE signal. The evaluator evaluates the soundness of the structure on the basis of the wave source distributions and the propagation velocity of the elastic waves.

Abstract: According to an embodiment, a detection system includes a detection device, an acoustic emission sensor, and a processing unit. The detection device detects a change that occurs in a structure or a change in an environment related to the structure. The acoustic emission sensor detects an acoustic emission wave produced from the structure. The processing unit performs first signal processing to process an acoustic emission signal indicating the acoustic emission wave, which is input from the acoustic emission sensor until a first period of time elapses after a detection signal is input from the detection device. The detection signal indicates that a change has occurred in the structure or the environment related to the structure.

Abstract: According to one embodiment, a structure evaluation system includes an impact imparting unit, a sensor, and a structure evaluation device. The impact imparting unit applies impacts to a structure. The impact imparting unit applies the impacts at a frequency equal to or less than a frequency determined in accordance with an intensity at which the impacts are imparted. The sensor detects elastic waves. The structure evaluation device evaluates a deterioration state of the structure on the basis of the detected elastic waves.

Abstract: According to one embodiment, a sensor adhesion state determination system includes a plurality of sensors, a calculator, and a determiner. Each of the plurality of sensors detects elastic waves. The calculator calculates peak frequencies of the elastic waves on the basis of the elastic waves detected by the plurality of sensors. The determiner determines the adhesion state of each of the sensors by comparing the peak frequencies with information serving as a determination reference.

Abstract: According to an embodiment, a detection system includes a plurality of sensor nodes and a sensor module. The plurality of sensor nodes detects sound waves generated from a prestressed concrete and converts the detected sound waves into detection signals. The sensor module is connected to the plurality of sensor nodes and receives the detection signals. The plurality of sensor nodes includes the sensor nodes in an operating state and the sensor nodes in a dormant state in which power consumption is held down as compared to the operating state. When magnitude of the detection signals is equal to or greater than a first threshold value, the sensor module switches the sensor node in the dormant state to the operating state.

Abstract: According to an embodiment, a structure evaluation system includes a plurality of sensors, a position locator, and an evaluator. The sensors detect an elastic wave generated from a structure. The position locator derives a source distribution of the elastic waves generated from the structure, caused by an impact on the structure. The evaluator evaluates a state of deterioration of the structure from characteristic parameters of the elastic waves in the source distribution.

Abstract: According to an embodiment, a structure evaluation system includes a plurality of AE sensors, a signal processor, a position locator, and an evaluator. The AE sensors detect an elastic wave generated from a structure. The signal processor performs signal processing on the elastic wave detected by the AE sensors and outputs an AE signal including information on the elastic wave. The position locator derives a source distribution indicating the distribution of sources of the elastic wave generated in the structure, using an AE signal caused by an impact on the structure. The evaluator evaluates a state of deterioration of a predetermined region of the structure from a density of the sources of the elastic wave obtained on the basis of the source distribution.

Abstract: According to an embodiment, a structure evaluation system includes a plurality of sensors, a position locator, a velocity calculator, and an evaluator. The sensors detect an elastic wave generated from a structure. The position locator derives a wave source distribution of the elastic waves generated from the structure, on the basis of the elastic waves. The velocity calculator derives a propagation velocity of the elastic wave generated from the structure, on the basis of the elastic waves. The evaluator evaluates the soundness of the structure on the basis of the wave source distribution and the propagation velocity of the elastic waves.

Abstract: According to an embodiment, a structure evaluation system includes a plurality of AE sensors, a signal processor, a position locator, a velocity calculator, and an evaluator. The AE sensors detect an elastic wave generated from a structure. The signal processor extracts an AE signal including information on the elastic wave by performing signal processing on the elastic wave detected by the AE sensor. The position locator derives a wave source distribution indicating a distribution of sources of the elastic waves generated in the structure on the basis of the AE signals. The velocity calculator derives a propagation velocity of the elastic wave generated in the structure on the basis of the AE signal. The evaluator evaluates the soundness of the structure on the basis of the wave source distributions and the propagation velocity of the elastic waves.

Abstract: A structure evaluation apparatus has an acquisitor and an evaluator. The acquisitor acquires a distribution that represents a distribution of strength of a reflected wave obtained by an electromagnetic radar scan to a reinforced concrete which comprises concrete and a material other than concrete. The evaluator calculates similarity, with reference to a reference region including the material in the distribution, of other regions including the material than the reference region in the distribution.

Abstract: According to one embodiment, a detection device is provided in a structure. The structure is constituted of: a first member; a second member provided on an opposite side of the first member; and a welded portion that is provided along an end of the second member facing the first member and fixes the first member and the second member. The detection device include: a plurality of acoustic emission sensors that are disposed so as to be separated from each other in a direction in which the welded portion extends and are configured to detect an elastic wave transmitted to the second member, each acoustic emission sensor being attached to the second member; and an outputter that outputs information, obtained from outputs of the plurality of the acoustic emission sensors, to an outside.

Abstract: According to an embodiment, a detection system includes a detection device, an acoustic emission sensor, and a processing unit. The detection device detects a change that occurs in a structure or a change in an environment related to the structure. The acoustic emission sensor detects an acoustic emission wave produced from the structure. The processing unit performs first signal processing to process an acoustic emission signal indicating the acoustic emission wave, which is input from the acoustic emission sensor until a first period of time elapses after a detection signal is input from the detection device. The detection signal indicates that a change has occurred in the structure or the environment related to the structure.

Abstract: In one embodiment, an image display apparatus includes: a projecting portion which projects in a second direction orthogonal to a first direction a first beam having a disparity image component which forms an image having a disparity in the first direction; a first deflecting portion which deflects the first beam in the second direction in a first plane having an axis in the first direction and an axis in the second direction, and obtains a second beam; and a second deflecting portion which further deflects in the first plane the second beam in a same direction as the second direction in which the first deflecting portion deflects the first beam, obtains a third beam and projects the third beam.

Abstract: According to one embodiment, an optical delay apparatus includes the following elements. The first retroreflector includes a first and a second reflection surface. The second retroreflector includes a third and a fourth reflection surface opposite to the first reflection surface. The third retroreflector includes a fifth and a sixth reflection surface opposite to the second reflection surface. The first driving mechanism moves the first retroreflector and a set of the second retroreflector and the third retroreflector relative to each other. The second retroreflector and the third retroreflector are misaligned with each other in a direction along a first line of intersection between the first reflection surface and the second reflection surface.

Abstract: According to one embodiment, an image display device includes a first lens member and a second lens member. The first lens member includes a plurality of first cylindrical lenses and a plurality of first projections. The plurality of first cylindrical lenses extend in a first direction and are arranged in a second direction that is perpendicular to the first direction. The plurality of first projections protrude between two adjacent ones of the first cylindrical lenses and extend in the first direction. The second lens member has a same composition as the first lens member, and includes a plurality of second cylindrical lens and a plurality of second projections. The plurality of second cylindrical lens has a same composition as the first cylindrical lenses. The plurality of second projections have a same composition as the first projections.