Wayne State University

Lawrence D Favro

Robert L Thomas

Pao-Kuang Kuo

Xiaoyan Han

Zhong Ouyang

Gang Sun

Hua Sui

Li Chen

Paul John Zombo

Robert E Shannon

Joachim W Baumann

Max Rothenfusser

Xioayan Han

Hui J Jin

A defect detection system for thermally imaging a structure that has been energized by sound energy. The system includes a transducer that couples a sound signal into the structure, where the sound signal induces acoustic chaos in the structure that causes defects in the structure to heat up. In one embodiment, the transducer is a broadband transducer. A thermal imaging camera images the structure when it is heated by the sound signal.

System and method for defect detection by inducing acoustic chaos

A defect detection system for thermally imaging a structure that has been energized by sound energy. The system includes a transducer that couples a sound signal into the structure, where the sound signal causes defects in the structure to heat up. In one embodiment, a hard metal disk is positioned between the transducer and the structure to help couple the sound energy from the transducer into the structure. A predetermined force is applied to the transducer and a pulse duration and a pulse frequency of the sound signal are selected so that the sound energy induces acoustic chaos in the structure, thus generating increased thermal energy. A thermal imaging camera images the structure when it is heated by the sound signal.

System and method for generating chaotic sound for sonic infrared imaging of defects in materials

A hand-held sound source for use in an infrared or thermal imaging system that detects sub-surface defects in a structure. The sound source includes a transducer that is positioned against the structure to emit a sound signal into the structure. The sound source further includes an adjustable spring that pushes the transducer against the structure with a predetermined amount of force so that the sound energy is effectively coupled into the structure. The sound source also includes three stabilizing legs that stabilize the transducer on the structure. The length of each leg can be adjustable relative to the length of the other legs so that the sound source can be used against irregular surfaces.

Hand-held sound source for sonic infrared imaging of defects in materials

A defect detection system for thermally imaging a structure that has been energized by a sound energy. The system includes a transducer that couples a sound signal into the structure, where the sound signal causes defects in the structure to heat up. In one embodiment, a non-linear coupling material is positioned between the transducer and the structure to couple the sound energy from the transducer to the structure. A predetermined force is applied to the transducer and a pulse duration and a pulse frequency of the sound signal are selected so that the sound energy induces acoustic chaos in the structure, thus generating increased thermal energy. A thermal imaging camera images the structure when it is heated by the sound signal.

System and method for acoustic chaos and sonic infrared imaging

A thermal imaging system for detecting cracks and defects in a structure. An ultrasonic transducer is coupled to the structure through a malleable coupler. Ultrasonic energy from the transducer causes the defects to heat up, which is detected by a thermal camera. A control unit is employed to provide timing and control for the operation of the ultrasonic transducer and the camera.

Thermal imaging system for detecting defects

A system for the thermal imaging of sonically or ultrasonically excited subsurface defects in a structure. The system includes a hand-held sound source, a thermal imaging camera and a control unit. The sound source emits pulses of sound energy into the structure, and the camera generates images of defects in the structure that are heated by the sound energy. The control unit controls the operation of the sound source on the camera for timing purposes. The sound source includes a transducer that is positioned against the structure at a desirable location. The source further includes a pair of legs that are also positioned against the structure to define a plane in combination with the transducer. The length of each leg is adjustable relative to the length of the transducer so that the gun can be used against irregular surfaces. The legs include a rubber tip to further prevent the transducer from slipping on the structure. In an alternate embodiment, the gun includes three transducers that define a plane and act to stabilize the gun against movement.

Hand-held sound source gun for infrared imaging of sub-surface defects in materials

A thermal imaging system for detecting cracks in a tooth. An ultrasonic dental cleaning tool is used to transmit ultrasonic energy through a jet of water to the tooth that causes cracks in the tooth to heat up. A thermal camera is used to detect the thermal radiation emitted by the heated cracks. The ultrasonic energy is in the form of a pulse where the frequency of the ultrasonic signal is substantially constant within the pulse. The control unit is employed to provide timing and control of the operation of the dental cleaning tool and the camera.

System and method for detecting cracks in a tooth by ultrasonically exciting and thermally imaging the tooth

A thermal imaging system for detecting cracks and defects in a component. An electromagnetic acoustic transducer (EMAT) is coupled to the component, and introduces pulsed sound signals therein. The sound signals cause the defects to heat up. The IR radiation from the heated pulses is detected by a thermal camera. The amplitude of the pulsed signals are substantially constant, and the frequency of the pulsed signal can be changed within each pulse. A control unit is employed to provide timing and control for the operation of the EMAT and the camera.

Miniaturized contactless sonic IR device for remote non-destructive inspection

A thermal imaging system for detecting cracks and defects in a component. An ultrasonic transducer is coupled to the specimen through a malleable coupler. Ultrasonic energy from the transducer causes the defects to heat up, which is detected by a thermal camera. The ultrasonic energy is in the form of a pulse where the frequency of the ultrasonic signal is substantially constant within the pulse. A control unit is employed to provide timing and control for the operation of the ultrasonic transducer and the camera.

Infrared imaging of ultrasonically excited subsurface defects in materials

A direct-view stereoscopic confocal microscope including a light source, an aperture plate, image collector, and first and second vibrators. The light source is used for illuminating a portion of a specimen and the aperture plate is used for passing a portion of the light emanating from the light source onto a portion of the specimen. The image collector is optically coupled to the illuminated portion of the specimen and acts to separate the image created by the illuminated portion of the specimen from the light illuminating the specimen. A first vibrator is coupled to the specimen for vibrating the specimen along a first axis and the second vibrator is coupled to the image collector, and synchronized with said first vibrator, for vibrating the collecting means along a second axis.

Direct-view stereoscopic confocal microscope

The assembly (10, 10') is a real time imaging device for detecting radiation from an object field (12) which is periodic in time. A video camera (14) detects emitted and reflected radiation from the object field (12) and produces a video signal of the image and a timing signal. A processor (16) synchronously averages successive video signals and stores same in an image buffer (26) to obtain an image from which has been eliminated unsynchronous noise. Alternatively, the elimination of unsynchronous or ambient noise may be performed partially or wholly within the camera (14) prior to processing.

Synchronous imaging system

A method for constructing a Nipkow disk using a zone plate disk, comprises the steps of constructing a zone plate disk, including the substep of disposing a plurality of focusing means a long a disk, wherein the plurality of focusing means have a common focal distance; placing a photographic plate at the focal distance of the plurality of focusing means; illuminating the plurality of focusing means with a light source such that the illumination is passed through the plurality of focusing means and focused onto the photographic plate thereby creating an image of a plurality of points of focused illumination; and capturing the image created on the photographic plate and using it to construct the Nipkow disk.

Method of constructing confocal microscope components

The assembly (10) utilizes real-time imaging for detecting radiation from an object field (12) which has a component which is periodic in time. A video camera (14) detects emitted and reflected radiation from the object field (12) and produces a video signal comprising a series of pixels representing a frame of the image. A dynamically averaged offset derived from the original video signal is subtracted from the video signal leaving only information from the time-varying component of the video object field. The resulting signal is digitized by a digitizer (18) contained in a processor (16). The processor (16) averages the successive frames as synchronous images based on the periodicity of the object field (12) to eliminate unsynchronous noise from the image and to display an image synchronous with the periodicity of the object field (12). Because the final video image is a digitization of the amplified difference, the dynamic range of the corrected image is greatly increased.

Dynamic offset to increase the range of digitization of video images

A confocal microscope comprises a focusing lens for focusing a light source onto a pin hole. The use of the lens for this purpose, when used within a confocal microscope apparatus, greatly reduces image artifacts and creates an increased transfer efficiently between the light source and the sample.

Confocal microscope

A single beam interferometer (10) comprises an intensity modulated laser beam (16) having a focus area for heating a test area (18) on the surface of a sample (12) producing a thermal bump (20). An unfocused probe laser beam (30) is directed toward the solid at an angle and has a beam area greater than the focus area of the heating beam (16). The sample (12) has a reflective surface for reflecting the probe beam (30). The reflected beam (31) comprises an AC beam portion (32) refracted by the thermal bump (20) and a DC beam portion (34) reflected off the unheated surface of the sample (12). The interference pattern (36) produced by the reflected beam (31) is detected and processed to obtain optical, elastic and thermal parameters of the sample (12).

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Huntington Woods, MI, United States of America

Lawrence D Favro