A method for compiling thermographic data including obtaining data indicative of a monotonically changing characteristic of a specimen, sequencing the data or a surrogate of the data into a plurality of groups, categorizing, within each group, the frequency distribution of an attribute of the data or an attribute of said surrogate data, and compiling, from one or more groups, a collection of two or more of the frequency distributions.

System for generating thermographic images using thermographic signal reconstruction

Pulsed thermography is an effective technique for quantitative prediction of defect depth within a specimen. Several methods have been reported in the literature. In this paper, using an analysis based on a theoretical one-dimensional solution of pulsed thermography, we analyzed four representative methods. We show that all of the methods are accurate and converge to the theoretical solution under ideal conditions. Three methods can be directly used to predict defect depth. However, because defect features that appear on the surface during a pulsed thermography test are always affected by three-dimensional heat conduction within the test specimen, the performance and accuracy of these methods differs for defects of various sizes and depths. This difference is demonstrated and evaluated from a set of pulsed thermography data obtained from a specimen with several flat-bottom holes as simulated defects.

Analysis of Pulsed Thermography Methods for Defect Depth Prediction

A method and apparatus for detecting, locating, isolating and controlling variations in the manufacturing process by transient thermography. A heat source (200) imparts heat to a surface which is radiated in the infrared region. Infrared sensors (204, 206, 208, 210) are coupled to a processor which tracks the physical characteristics of the sample, and provides feedback to a central process controller to make adjustments to the manufacturing process. The sample can be a continuous product such as a green powder metal sheet or tobacco product.

Process control by transient thermography

An acoustic detector based on rupture event scanning (“REVS”) with a detection setup allowing the monitoring of REVS signals near the driving frequency and with optimized impedance matching between the REVS crystal and the front-end of the detection circuitry for use in detecting the presence of particles such as bacteria, viruses, or other particulates in liquid samples with extreme high sensitivity.

System and method for detecting particles

A method and system for non-destructive, reference-free thermographic detection of sub-surface defects uses an infrared camera to capture images of a sample that has been heated and allow to cool to equilibrium temperature. The temperature-time data obtained for each pixel in each image is converted into the logarithmic domain and a least squares fit is conducted on the data to generate a polynomial expression corresponding to the temperature-time data for a given pixel. This polynomial expression can be transformed into the original time domain to obtain temperature-time data with improved signal-to-noise characteristics. Defects can be detected by observing the zero-crossing characteristic of the second derivative of the polynomial.

Temporal noise reduction, compression and analysis of thermographic image data sequences

The present invention relates to transient depth thermography; a nondestructive testing technique and system for locating flaws within an object. The system, which comprises a heater for heating the surface of the object; a recorder for recording pixel intensity for each pixel on the heated surface; a means for determining pixel contrast from the pixel intensity; and a means for determining the size and location of flaws within the object based upon the pixel contrast; monitors each pixels' contrast for successive thermal images and utilizes those pixel contrasts determining the location of a flaw within the object. The object surface and the respective underlying flaws can then be depicted on a color spectrum image print which correlates the flaw depth with a particular color.

Nondestructive testing: transient depth thermography

An arrangement for detecting metallic particles carried by a fluid includes a metallic probe member which surrounds an elongated passage through which the fluid flows and which is constituted by a split tube having two marginal portions delimiting a gap which extends along said passage and completely separates the marginal portions from one another. Capacitors are arranged at the gap and alternating electric current is caused to flow in the probe member around the passage so that the probe member and the capacitors form a tank circuit having resonance characteristics that are influenced by any inclusion then present in the passage in a manner dependent on the electromagnetic properties of the inclusion. The character of any metallic particle then present in the passage is determined from variations in the alternating electric current that reflect the influence of such metallic particle on the resonance characteristics.

In-line metallic debris particle detection system

In-line metallic debris particle detection probe and resonant evaluation system utilizing the same

An arrangement for detecting metallic particles carried by a fluid includes an elongated single turn coil (12) which surrounds an elongated passage (11) through which the fluid flows and has a length as considered in the longitudinal direction of the passage (11) that is at least equal to the diameter of the coil (12). Two longitudinally extending portions (13, 14) of the coil (12) delimit a gap (15) which extends along the passage (11) and completely physically separates the portions (13, 14). At least one capacitor (16) is arranged directly at the gap (15) and is electrically connected between the portions (13, 14) to form an electronic resonator circuit with the coil (12). The resonator circuit (12, 16) is driven at all times at its resonant frequency as influenced by the presence of metallic particles in the passage (11) and the operating temperature. The inductance to capacitance ratio of the resonator circuit (15, 16) has the value of at most one to four.

William A. Veronesi

Papers

Nondestructive testing: transient depth thermography

In-line metallic debris particle detection system

In-line metallic debris particle detection probe and resonant evaluation system utilizing the same

Arrangement for detecting metallic particles carried by a fluid

Gerät zum erfassen von metallteilchen, die in einem fluid mitgeführt werden.