scholarly journals Evaluating spatial and frequency domain enhancement techniques on dental images to assist dental implant therapy

Author(s):  
Shashikala J. ◽  
Thangadurai N.

<span lang="EN-US">Dental imaging provides the patient's anatomical details for the dental implant based on the maxillofacial structure and the two-dimensional geometric projection, helping clinical experts decide whether the implant surgery is suitable for a particular patient. Dental images often suffer from problems associated with random noise and low contrast factors, which need effective preprocessing operations. However, each enhancement technique comes with some advantages and limitations. Therefore, choosing a suitable image enhancement method always a difficult task. In this paper, a universal framework is proposed that integrates the functionality of various enhancement mechanisms so that dentists can select a suitable method of their own choice to improve the quality of dental image for the implant procedure. The proposed framework evaluates the effectiveness of both frequency domain enhancement and spatial domain enhancement techniques on dental images. The selection of the best enhancement method further depends on the output image perceptibility responses, peak signal-to-noise ratio (PSNR), and sharpness. The proposed framework offers a flexible and scalable approach to the dental expert to perform enhancement of a dental image according to visual image features and different enhancement requirements.</span>

2012 ◽  
Vol 490-495 ◽  
pp. 548-552
Author(s):  
Meng Ling Zhao ◽  
Min Xia Jiang

Because of the based on S3C6410 Field information recorder mine- underground non-uniform illumination and mine- underground non-uniform illumination that a large of noise collected and transferred,image is low contrast ,dim and dark. Based on the theory of Donoho's wavelet threshold denoising, several typical wavelet threshold denoising methods are compared.the best denoising effect of peak signal to noise ratio is obtained. The image enhancement method that combination of the adaptive thresholding denoising and histogram equalization is proposed. The experiment result shows that the method has a good denoising performance, which removed the readout noise of CCD Camera,at the same time, image quality is improved .So the wavelet enhancement in image processing of mine- underground can improve image quality.


2021 ◽  
Vol 257 ◽  
pp. 02048
Author(s):  
Mu Li ◽  
Tao Li ◽  
Lei Zheng ◽  
Fen Xu

It is one of the important means to ensure the safety of transmission line and its equipment to realize the rapid identification and accurate diagnosis of visual defect fault points of transmission line. In this paper, an adaptive infrared image enhancement algorithm is proposed based on the research of infrared image features and various image enhancement algorithms. The algorithm first filters the infrared image to remove the random noise and improve the signal-to-noise ratio of the image; then, based on the histogram analysis of the infrared image, adaptively selects the upper and lower thresholds of the gray histogram, and uses the histogram segmentation to divide the infrared image into three parts: target, target and background aliasing, and background. Finally, through the gray analysis of the three distributions, the algorithm can extract the gray image. Finally, infrared image background suppression and target enhancement are realized. By comparing the effect before and after image enhancement, it is proved that the algorithm has strong practicability.


2013 ◽  
Vol 291-294 ◽  
pp. 2437-2441 ◽  
Author(s):  
Kang Ke Liu ◽  
Jian Hua Wang

Visual perception can provide environmental information for the control strategy of the unmanned surface vehicle, and the detection of wave grade is an important aspect of visual perception. Based on the theory of Fourier transform, this paper analyzes frequency domain characteristics of the wave image in different light and sea state. According to the relationship between different rectangle ring energy percentage, a method of judging wave grade is proposed. Firstly, the characteristic of the wave image is enhanced through histogram equalization; then, the image is transformed to frequency domain by FT; thirdly, the image features are extracted by the method of rectangle ring energy percentage; finally, waves grade are judged by the relationship between the first and the second stage rectangle ring energy percentage. The experimental results show that this method can effectively detect the wave grade and have the advantage that light condition has less effect on it.


2021 ◽  
Vol 9 (2) ◽  
pp. 225
Author(s):  
Farong Gao ◽  
Kai Wang ◽  
Zhangyi Yang ◽  
Yejian Wang ◽  
Qizhong Zhang

In this study, an underwater image enhancement method based on local contrast correction (LCC) and multi-scale fusion is proposed to resolve low contrast and color distortion of underwater images. First, the original image is compensated using the red channel, and the compensated image is processed with a white balance. Second, LCC and image sharpening are carried out to generate two different image versions. Finally, the local contrast corrected images are fused with sharpened images by the multi-scale fusion method. The results show that the proposed method can be applied to water degradation images in different environments without resorting to an image formation model. It can effectively solve color distortion, low contrast, and unobvious details of underwater images.


2021 ◽  
Vol 11 (11) ◽  
pp. 5055
Author(s):  
Hong Liang ◽  
Ankang Yu ◽  
Mingwen Shao ◽  
Yuru Tian

Due to the characteristics of low signal-to-noise ratio and low contrast, low-light images will have problems such as color distortion, low visibility, and accompanying noise, which will cause the accuracy of the target detection problem to drop or even miss the detection target. However, recalibrating the dataset for this type of image will face problems such as increased cost or reduced model robustness. To solve this kind of problem, we propose a low-light image enhancement model based on deep learning. In this paper, the feature extraction is guided by the illumination map and noise map, and then the neural network is trained to predict the local affine model coefficients in the bilateral space. Through these methods, our network can effectively denoise and enhance images. We have conducted extensive experiments on the LOL datasets, and the results show that, compared with traditional image enhancement algorithms, the model is superior to traditional methods in image quality and speed.


2021 ◽  
pp. 238008442110494
Author(s):  
A. Rudeejaraswan ◽  
P.P. Pisarnturakit ◽  
N. Mattheos ◽  
A. Pimkhaokham ◽  
K. Subbalekha

Introduction: As implant therapy is a widely applied treatment modality, general dentists are in the frontline of maintaining health in patients with implants. It is however unknown to what extent general dentists are competent and feel prepared to deliver maintenance of implants to patients. Objectives: The aim of this study was to investigate the attitudes and self-reported and objectively assessed competences of general dentists with maintenance of dental implants in patients. Methods: A questionnaire designed and validated for the purpose of the study, including attitudes and self-reported and objectively assessed competences, was distributed by means of an online platform. Results: Data from 429 questionnaires were included in the study. Half of the participants were 28 to 33 y old and 78% had been working <10 y. Seventy-eight percent believed that dental implant maintenance should be performed by general dentists, but only 51% were prepared to do this, citing obstacles such as insufficient knowledge and limitations of their working environment. The mean ± SD objectively assessed competence score was 8.97 ± 2.74 of 17. There were significant differences (P < 0.001, 1-way analysis of variance) in the scores among dentists who offered the full range of maintenance and management of complications (10.83 ± 2.45) with those willing to provide comprehensive oral examination and implant maintenance only (9.31 ± 2.73), those offering comprehensive examination but unwilling to conduct maintenance (8.22 ± 2.28), and those who refer all dental implant patients elsewhere (7.2 ± 2.66). Around half of the dentists believed that implants last for life. Conclusions: While general dentists appeared to largely acknowledge the importance of providing implant maintenance care and present with positive attitudes, a large portion was unwilling to engage with maintenance of implants in patients and appeared to lack essential competences to this end. The main obstacles for providing implant maintenance care included insufficient knowledge and lack of a properly equipped clinical environment. Knowledge Transfer Statement: The results of this study can identify deficiencies in the currently available maintenance competences and schemes for patients with implants. These results can also help dental professionals, scientific bodies, and associations to design appropriate education and professional development strategies that can strengthen the confidence and competences of general dentists, thus offering better service to the public.


2011 ◽  
Vol 403-408 ◽  
pp. 1817-1822
Author(s):  
Xi Feng Zhou ◽  
Xiao Wu ◽  
Qian Gang Guo

The quality of ultrasonic flaw echo signal is the foundation of achieving qualitative and quantitative analysis in the in ultrasonic flaw detection. In practice, the flaw echo signals are often contaminated or even annihilation by random noise. According to the characteristics of ultrasonic flaw echo signal, wavelet packet has more accurate local analysis ability in low frequency and high frequency part. This paper discusses de-noising in ultrasonic signals based on wavelet packet analysis, and proposes an improved threshold approach for de-noising. The results show that: It remarkably raises the signal-to-noise ratio of ultrasonic flaw echo signal and improves the quality of signal with improved wavelet packet threshold.


An efficient bandwidth allocation and dynamic bandwidth access away from its previous limits is referred as cognitive radio (CR).The limited spectrum with inefficient usage requires the advances of dynamic spectrum access approach, where the secondary users are authorized to utilize the unused temporary licensed spectrum. For this reason it is essential to analyze the absence/presence of primary users for spectrum usage. So spectrum sensing is the main requirement and developed to sense the absence/ presence of a licensed user. This paper shows the design model of energy detection based spectrum sensing in frequency domain utilizing Binary Symmetric Channel (BSC) ,Additive white real Gaussian channel (AWGN), Rayleigh fading channel users for 16-Quadrature Amplitude Modulation(QAM) which is utilized for the wide band sensing applications at low Signal to noise Ratio(SNR) level to reduce the false error identification. The spectrum sensing techniques has least computational complexity. Simulink model for the energy detection based spectrum sensing using frequency domain in MATLAB 2014a.


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