scholarly journals Automated Defect Detection Using Threshold Value Classification Based on Thermographic Inspection

2021 ◽  
Vol 11 (17) ◽  
pp. 7870
Author(s):  
Seungju Lee ◽  
Yoonjae Chung ◽  
Ranjit Shrestha ◽  
Wontae Kim
Keyword(s):  
Infrared Thermography ◽  
Defect Detection ◽  
High Speed ◽  
Signal To Noise Ratio ◽  
Threshold Value ◽  
Large Area ◽  
Reliable Technique ◽  
Binary Images ◽  
Additional Signal ◽  
Phase Images

Active infrared thermography is an attractive and reliable technique used for the non-destructive evaluation of various materials and structures, because it enables non-contact, large area, high-speed, quantitative, and qualitative inspection. However, the defect detectability is significantly deteriorated due to the excitation of a non-uniform heat source and surrounding environmental noise, requiring additional signal processing and image characterization. The lock-in infrared thermography technique has been proven to be an effective method for quantitative evaluation by extracting amplitude and phase images from a 2D thermal sequence, but it still involves a lot of noise, providing difficulties in detection. Therefore, this study explored the possibility of improving the signal-to-noise ratio by applying filtering to a stainless-steel plate with circular defects. Thereafter, automated defect detection was performed based on the threshold value through the binary images. In addition, a comparative analysis was performed to evaluate the detectability according to the presence or absence of a filtering application.

Morphological based Medical Image Processing on Cervical Cytology Cancer Images using Connected Component Techniques

2021 ◽  
Vol 17 ◽  
Author(s):  
P. Robert ◽  
A. Celine Kavida
Keyword(s):  
Cervical Cancer ◽  
Signal To Noise Ratio ◽  
Similarity Index ◽  
Structural Similarity ◽  
Threshold Value ◽  
Good Precision ◽  
Connected Component ◽  
Binary Images ◽  
Proposed Model ◽  
Structural Content

: Cervical cancer is the fourth most common cancer in women. In 2018, it was estimated that 570000 women were diagnosed with cervical cancer worldwide, and about 311000 women died from the disease. An efficient technique is essential for solving the complication in the diagnosis of cervical cancer images. In this research, a new method is developed for cervical cancer image segmentation. First, the RGB image is converted into an HSI color model. Then, the thresholding is applied to the saturation and intensity components to get binary images. These binary images are combined to get a new mask. Using the connected component concept, nucleus and cytoplasm are segmented accurately. For the performance evaluation, peak signal-to-noise ratio (PSNR), mean square error (MSE), structural similarity index (SSIM), image quality index (IQI), structural content (SC), normalized cross-correlation (NK), precision (PR), recall (RC), the average difference (AD), and image fidelity (IF) are taken. The proposed techniques’ highest PSNR values are 44.2341, 46.7953, 60.5925, and 61.4862, respectively. The proposed segmentation technique can attain a high PSNR (>40db) value at a threshold value equal to 0.1. Also proposed approach attains good precision, recall, and SSIM values. The lowest MSE values using proposed segmentation techniques are 0.0454, 0.0351, 0.0924, and 0.0271 individually. The AD, NK, SC, NAE, and LMSE values for the implemented approach are low, showing that the segmented image’s quality is very good. Thus, the proposed model performed better compared to other methods.

High Speed Non-Contact Ultrasonic Guided Wave Inspections of Rails

2014 ◽  
Author(s):  
Stefano Mariani ◽  
Thompson V. Nguyen ◽  
Francesco Lanza di Scalea ◽  
Mahmood Fateh
Keyword(s):  
Defect Detection ◽  
High Speed ◽  
Surface Characterization ◽  
Rail Steel ◽  
Signal To Noise Ratio ◽  
High Reliability ◽  
False Positive Rate ◽  
Roc Curves ◽  
Guided Wave ◽  
Ultrasonic Guided Wave

This paper describes a new system for high-speed and non-contact rail defect detection being developed at the University of California at San Diego (UCSD). A prototype using an ultrasonic air-coupled guided wave signal generation and air-coupled signal detection has been tested at the UCSD Rail Defect Farm. This solution presents an improvement over the previously considered laser/air-coupled hybrid system because it replaces the costly and hard-to-maintain laser with a much cheaper, faster, and easier-to-maintain air-coupled transmitter. In addition to a real-time statistical analysis algorithm, the prototype uses a specialized filtering approach to mitigate the inherently poor signal-to-noise ratio of the air-coupled ultrasonic measurements in rail steel. The laboratory results indicate that the prototype is able to detect internal rail defects with a high reliability. Various aspects of the prototype have been designed with the aid of numerical analyses. In particular, simulations of ultrasonic guided wave propagation in rails have been performed using a Local Interaction Simulation Approach (LISA) algorithm. Many of the system operating parameters were selected based on Receiver Operating Characteristic (ROC) curves, which provide a quantitative manner to evaluate different detection performances based on the trade-off between detection rate and false positive rate. Extensions of the system capability are planned to add rail surface characterization to the internal rail defect detection to optimize rail grinding operations.

Efficient Steganography Algorithm Based On DCT And Entropy Thresholding Technique

2018 ◽  
Vol 8 (1) ◽  
pp. 45
Author(s):  
Satvir Singh
Keyword(s):  
Relative Entropy ◽  
Experimental Work ◽  
Random Function ◽  
Signal To Noise Ratio ◽  
Binary Sequence ◽  
Threshold Value ◽  
Absolute Difference ◽  
Secret Message ◽  
Signal To Noise ◽  
Confidential Information

Steganography is the special art of hidding important and confidential information in appropriate multimedia carrier. It also restrict the detection of  hidden messages. In this paper we proposes steganographic method based on dct and entropy thresholding technique. The steganographic algorithm uses random function in order to select block of the image where the elements of the binary sequence of a secret message will be inserted. Insertion takes place at the lower frequency  AC coefficients of the  block. Before we insert the secret  message. Image under goes dc transformations after insertion of the secret message we apply inverse dc transformations. Secret message will only be inserted into a particular block if  entropy value of that particular block is greater then threshold value of the entropy and if block is selected by the random function. In  Experimental work we calculated the peak signal to noise ratio(PSNR), Absolute difference , Relative entropy. Proposed algorithm give high value of PSNR  and low value of Absolute difference which clearly indicate level of distortion in image due to insertion of secret message is reduced. Also value of  relative entropy is close to zero which clearly indicate proposed algorithm is sufficiently secure. 

Evaluvation of Multiresolution Watermarking Algorithm

2017 ◽  
Vol 7 (8) ◽  
pp. 85
Author(s):  
S. Thabasu Kannan ◽  
S. Azhagu Senthil
Keyword(s):  
Digital Watermarking ◽  
Wavelet Transformation ◽  
Signal To Noise Ratio ◽  
Rapid Development ◽  
Threshold Value ◽  
Discrete Wavelet ◽  
Digital Production ◽  
Common Framework ◽  
Sampling Operation ◽  
Watermarking Scheme

Now-a-days watermarking plays a pivotal role in most of the industries for providing security to their own as well as hired or leased data. This paper its main aim is to study the multiresolution watermarking algorithms and also choosing the effective and efficient one for improving the resistance in data compression. Computational savings from such a multiresolution watermarking framework is obvious. The multiresolutional property makes our watermarking scheme robust to image/video down sampling operation by a power of two in either space or time. There is no common framework for multiresolutional digital watermarking of both images and video. A multiresolution watermarking based on the wavelet transformation is selected in each frequency band of the Discrete Wavelet Transform (DWT) domain and therefore it can resist the destruction of image processing.   The rapid development of Internet introduces a new set of challenging problems regarding security. One of the most significant problems is to prevent unauthorized copying of digital production from distribution. Digital watermarking has provided a powerful way to claim intellectual protection. We proposed an idea for enhancing the robustness of extracted watermarks. Watermark can be treated as a transmitted signal, while the destruction from attackers is regarded as a noisy distortion in channel.  For the implementation, we have used minimum nine coordinate positions. The watermarking algorithms to be taken for this study are Corvi algorithm and Wang algorithm. In all graph, we have plotted X axis as peak signal to noise ratio (PSNR) and y axis as Correlation with original watermark. The threshold value ά is set to 5. The result is smaller than the threshold value then it is feasible, otherwise it is not.

Analysis of the Visualization Region in Near-Wall Fluid Layer by High-Speed Infrared Thermography

2020 ◽  
Vol 75 (2) ◽  
pp. 143-147
Author(s):  
A. M. Shagiyanova ◽  
E. Yu. Koroteeva ◽  
I. A. Znamenskaya ◽  
M. E. Dashyan ◽  
L. A. Blagonravov ◽  
...  
Keyword(s):  
Infrared Thermography ◽  
High Speed ◽  
Fluid Layer ◽  
Near Wall

Evaluation of Package Defects by Thermal Imaging Techniques

2002 ◽  
Author(s):  
Yongmei Liu ◽  
Rajen Dias
Keyword(s):  
Infrared Thermography ◽  
Thermal Imaging ◽  
High Speed ◽  
Imaging Techniques ◽  
Thermal Response ◽  
Analysis Tool ◽  
Nondestructive Analysis ◽  
Ir Camera ◽  
External Heating

Abstract Study presented here has shown that Infrared thermography has the potential to be a nondestructive analysis tool for evaluating package sublayer defects. Thermal imaging is achieved by applying pulsed external heating to the package surface and monitoring the surface thermal response as a function of time with a high-speed IR camera. Since the thermal response of the surface is affected by the defects such as voids and delamination below the package surface, the technique can be used to assist package defects detection and analysis.

40 Gb/s High-speed mode-division multiplexing transmission employing NRZ modulation format

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Rabiu Imam Sabitu ◽  
Nafizah Goriman Khan ◽  
Amin Malekmohammadi
Keyword(s):  
System Performance ◽  
High Speed ◽  
Direct Detection ◽  
Signal To Noise Ratio ◽  
Optical Signal ◽  
Threshold Power ◽  
Modulation Format ◽  
Transmission Distance ◽  
Mode Division Multiplexing ◽  
Speed Mode

AbstractThis report examines the performance of a high-speed MDM transmission system supporting four nondegenerate spatial modes at 10 Gb/s. The analysis adopts the NRZ modulation format to evaluate the system performance in terms of a minimum power required (PN) and the nonlinear threshold power (PTH) at a BER of 10−9. The receiver sensitivity, optical signal-to-noise ratio, and the maximum transmission distance were investigated using the direct detection by employing a multimode erbium-doped amplifier (MM-EDFA). It was found that by properly optimizing the MM-EDFA, the system performance can significantly be improved.

scholarly journals High-speed high-efficiency large-area resonant cavity enhanced p-i-n photodiodes for multimode fiber communications

2001 ◽  
Vol 13 (12) ◽  
pp. 1349-1351 ◽  
Author(s):  
M. Gokkavas ◽  
O. Dosunmu ◽  
M.S. Unlu ◽  
G. Ulu ◽  
R.P. Mirin ◽  
...  
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Resonant Cavity ◽  
Multimode Fiber ◽  
Large Area ◽  
Fiber Communications
Sign in / Sign up

Export Citation Format

Share Document