Effect of Modulation Frequency on Detecting Metal Materials with Microcracks Based on Ultrasound Infrared Lock-in Thermography

2011 ◽  
Vol 314-316 ◽  
pp. 1387-1390
Author(s):  
Qing Ju Tang ◽  
Jun Yan Liu ◽  
Yang Wang
Keyword(s):  
Testing Effect ◽  
Signal To Noise Ratio ◽  
Modulation Frequency ◽  
Experimental Platform ◽  
Testing Method ◽  
Micro Cracks ◽  
Phase Images ◽  
Metal Materials ◽  
Lock In ◽  
Non Destructive

The non-destructive ultrasound infrared lock-in thermography (ULT) testing method was used to detect metal specimens with defects of micro cracks. An experimental platform was built based on the analysis of the ULT principle. Experiments had been carried out to Q235 plates with different testing parameters. The testing effect of thermography, amplitude and phase images was analyzed, and the relations between amplitude difference, phase difference, signal-to-noise ratio and modulation frequency were discussed.

Theoretical and Experimental Study on Nondestructive Pulse Phase Infrared Thermography Testing Technology

2011 ◽  
Vol 314-316 ◽  
pp. 1483-1486
Author(s):  
Qing Ju Tang ◽  
Jun Yan Liu ◽  
Yang Wang
Keyword(s):  
Experimental Study ◽  
Infrared Thermography ◽  
Testing Effect ◽  
Experimental Results ◽  
Composite Specimen ◽  
Experimental Platform ◽  
Phase Images ◽  
Testing Technology ◽  
Pulsed Phase Thermography ◽  
Non Destructive

The non-destructive pulsed phase thermography technique was used to detect metal specimen with flat blind-bottom holes and composite specimen with sticky areas. An experimental platform was built base on the analysis of the pulsed phase thermography testing principle. Experimental results show the different testing effect of the original thermography, amplitude and phase images.

Effects of Magnetic Concentrator on MFL Signals Using FEA

2011 ◽  
Vol 204-210 ◽  
pp. 1956-1959
Author(s):  
Qiang Song
Keyword(s):  
Signal To Noise Ratio ◽  
Axial Component ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Element Analysis ◽  
Leakage Flux ◽  
Testing Method ◽  
Detection Schemes ◽  
Non Destructive ◽  
Flux Leakage

Magnetic flux leakage (MFL) is a non-destructive testing method used to inspect ferrous materials. However, there are a variety of factors that can affect the MFL inspection tool’s ability to detect and characterize anomalies. MFL signals obtained during the inspection of pipes have been simulated using 3D finite element analysis (FEA) and the effects of magnetic concentrator on MFL signals are investigated. Measurements of the leakage flux with various defect depths or widths indicate that the axial component of MFL are improved by magnetic concentrator with the result that significant advantages could be obtained in defect detection schemes, in that the signal to noise ratio (SNR) of MFL signals can be improved by magnetic concentrator.

scholarly journals Enhancement of signal-to-noise ratio for fluorescence endoscope image based on fast digital lock-in algorithm

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Huiquan Wang ◽  
Meng Hu ◽  
Fang Xia ◽  
Meng Guo ◽  
Shengzhao Zhang ◽  
...  
Keyword(s):  
Image Processing ◽  
White Light ◽  
Near Infrared ◽  
Signal To Noise Ratio ◽  
Infrared Light ◽  
Signal To Noise ◽  
Experimental Platform ◽  
Fluorescence Images ◽  
Lock In

In this paper, the signal-to-noise ratios (SNR) of two image channels were enhanced with the fast digital lock-in algorithm. In order to simultaneously improve the quality of white and fluorescence images obtained by fluorescence endoscope, and improve the SNR to achieve a better image processing effect, two sources of white light and near-infrared light of a fluorescence endoscope were modulated, then the acquired images were demodulated into white and fluorescence images. A fluorescent endoscope experimental platform was setup to acquire endoscopic images of a target dyed by indocyanine green. The experimental results showed that the SNR of white and fluorescent images without the lock-in algorithm were 36.56 dB and 33.47 dB, respectively. However, with the lock-in algorithm, the SNR of white and fluorescent images were 39.54 dB and 35.70 dB, respectively. The SNR of white and fluorescent images was increased by 8.2% and 6.7%, respectively, by appling the digital lock-in algorithm. Therefore, this novel fluorescence endoscope based on the fast digital lock-in algorithm can rapidly and simultaneously obtain two-channel images of white light and fluorescence, effectively enhance the SNR of white and fluorescent images, and improve the imaging quality.

Lock-In-Thermography for 3-Dimensional Localization of Electrical Defects inside Complex Packaged Devices

2008 ◽  
Author(s):  
C. Schmidt ◽  
F. Altmann ◽  
C. Grosse ◽  
A. Lindner ◽  
V. Gottschalk
Keyword(s):  
Integrated Circuits ◽  
Hot Spots ◽  
Signal To Noise Ratio ◽  
Thermal Response ◽  
Temperature Fields ◽  
Single Chip ◽  
3 Dimensional ◽  
Lateral Localization ◽  
Lock In ◽  
Non Destructive

Abstract It has been shown that microscopic Lock-in-Thermography (LiT) can be used for localization of electrical active defects like shorts and resistive opens in integrated circuits. This paper deals with the application of LiT for non-destructive failure analysis of fully packaged single and multi chip devices. In this case inner hot spots generated by the electrical defects typically can not be imaged directly because the mold compound or adhesives above are not IR transparent. Inner hot spots can only be detected by measuring the corresponded temperature field at the device surface. By means of failed and test devices will be shown, that LiT is sensitive enough to measure such temperature fields. In addition to the lateral localization of inner hot spots its depth can also be determined by measuring the phase shift between the electrical excitation and the thermal response at the device surface. Furthermore, the influence of the lock-in-frequency and mold compound thickness to lateral resolution and signal to noise ratio will be discussed. Using real failed single chip and stacked die devices two analysis flows were demonstrated to locate inner defects.

Failure Analysis Strategies for Multistacked Memory Devices with TSV Interconnects

2015 ◽  
Author(s):  
Frank Altmann ◽  
Christian Grosse ◽  
Falk Naumann ◽  
Jens Beyersdorfer ◽  
Tony Veches
Keyword(s):  
Failure Analysis ◽  
Focused Ion Beam ◽  
Failure Modes ◽  
Ion Beam ◽  
Memory Devices ◽  
Metallographic Cross Section ◽  
Electron Beam Induced Current ◽  
Thermal Simulations ◽  
Lock In ◽  
Non Destructive

Abstract In this paper we will demonstrate new approaches for failure analysis of memory devices with multiple stacked dies and TSV interconnects. Therefore, TSV specific failure modes are studied on daisy chain test samples. Two analysis flows for defect localization implementing Electron Beam Induced Current (EBAC) imaging and Lock-in-Thermography (LIT) as well as adapted Focused Ion Beam (FIB) preparation and defect characterization by electron microscopy will be discussed. The most challenging failure mode is an electrical short at the TSV sidewall isolation with sub-micrometer dimensions. It is shown that the leakage path to a certain TSV within the stack can firstly be located by applying LIT to a metallographic cross section and secondly pinpointing by FIB/SEM cross-sectioning. In order to evaluate the potential of non-destructive determination of the lateral defect position, as well as the defect depth from only one LIT measurement, 2D thermal simulations of TSV stacks with artificial leakages are performed calculating the phase shift values per die level.

A Comparative Study on Infrared Thermography during Ultrasonic Fatigue Testing of Cast Steel 42CrMo4 and Cast Aluminium Alloy AlSi7Mg

2013 ◽  
Vol 592-593 ◽  
pp. 501-504 ◽  
Author(s):  
Dominik Krewerth ◽  
Anja Weidner ◽  
Horst Biermann
Keyword(s):  
Aluminium Alloy ◽  
Infrared Thermography ◽  
Fatigue Testing ◽  
Cast Steel ◽  
Material Testing ◽  
Initiation Point ◽  
Testing Method ◽  
Cast Aluminium ◽  
Ultrasonic Fatigue ◽  
Non Destructive

The present paper illustrates a comparison of infrared thermography during ultrasonic fatigue testing of cast steel 42CrMo4 and cast aluminium alloy AlSi7Mg. Against the background of different material properties (e.g. mechanical properties as well as thermal properties) the benefit of this non-destructive material testing method in terms of determining the crack initiation point and time during fatigue testing as well as crack propagation is evaluated and discussed. Moreover, correlations between fractography and infrared thermography are performed for both materials.

Excitation-invariant pre-processing of thermographic data

2018 ◽  
Vol 232 (4) ◽  
pp. 435-446
Author(s):  
Serafeim Moustakidis ◽  
Athanasios Anagnostis ◽  
Apostolos Chondronasios ◽  
Patrik Karlsson ◽  
Kostas Hrissagis
Keyword(s):  
Composite Structures ◽  
Signal To Noise Ratio ◽  
Signal Reconstruction ◽  
Test Material ◽  
Test Surface ◽  
Nondestructive Testing Method ◽  
Uneven Heating ◽  
Processing Techniques ◽  
Inspection Techniques ◽  
Non Destructive

There is a large number of industries that make extensive use of composite materials in their respective sectors. This rise in composites’ use has necessitated the development of new non-destructive inspection techniques that focus on manufacturing quality assurance, as well as in-service damage testing. Active infrared thermography is now a popular nondestructive testing method for detecting defects in composite structures. Non-uniform emissivity, uneven heating of the test surface, and variation in thermal properties of the test material are some of the crucial factors in experimental thermography. These unwanted thermal effects are typically coped with the application of a number of well-established thermographic techniques including pulse phase thermography and thermographic signal reconstruction. This article addresses this problem of the induced uneven heating at the pre-processing phase prior to the application of the thermographic processing techniques. To accomplish this, a number of excitation invariant pre-processing techniques were developed and tested in this article addressing the unwanted effect of non-uniform excitation in the collected thermographic data. Various fitting approaches were validated in light of modeling the non-uniform heating effect, and new normalization approaches were proposed following a time-dependent framework. The proposed pre-processing techniques were validated on a testing composite sample with pre-determined defects. The results demonstrated the effectiveness of the proposed processing algorithms in terms of removing the unwanted heat distribution effect along with the signal-to-noise ratio of the produced infrared images.

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