Image blurring effects due to depth discontinuities: blurring that creates emergent image details

1992 ◽  
Vol 10 (10) ◽  
pp. 689-698 ◽  
Author(s):  
Thang C Nguyen ◽  
Thomas S Huang
Keyword(s):  
Depth Discontinuities ◽  
Image Blurring ◽  
Image Details

Homomorphic Filter Based Image Watermarking

2015 ◽  
Vol 781 ◽  
pp. 543-546
Author(s):  
Piyanart Chotikawanid ◽  
Kharittha Thongkor ◽  
Thumrongrat Amornraksa
Keyword(s):  
Stream Cipher ◽  
Color Image ◽  
Image Watermarking ◽  
Blind Detection ◽  
Secret Key ◽  
Natural Logarithm ◽  
Detection Approach ◽  
Image Blurring ◽  
Homomorphic Filter ◽  
Image Details

This paper proposes a spatial domain image watermarking method based on homomorphic filter. In the proposed method, after applying the homomorphic filter to the host color image, a watermark image is embedded into the natural logarithm reflectance component of the image. Based on the concept that the reflectance component contains most of the image details with low energy, the watermark energy added to this component will be imperceptually noticed by the human eye. The embedding watermark is also protected by a key-based stream cipher, so that without the correct secret key, one cannot reconstruct the watermark. To identify the existence of the embedded watermark, the semi-blind detection approach is applied. The performance of the proposed method in terms of correlation coefficient between the original and extracted watermarks is measured and presented. Its robustness against image blurring and image sharpening at various strengths is also evaluated. The results show the potential of the proposed method for a practical system.

scholarly journals Switching median filter for suppressing multi-pixel impulse noise

2021 ◽  
Vol 45 (4) ◽  
pp. 580-588
Author(s):  
A.A. Trubitsyn ◽  
E.Yu. Grachev
Keyword(s):  
Impulse Noise ◽  
Noise Suppression ◽  
Median Filter ◽  
Background Intensity ◽  
X Ray ◽  
Switching Median Filter ◽  
Image Blurring ◽  
Intensity Increment ◽  
Single Pixel ◽  
Image Details

This paper proposes a new switching median filter for suppressing multi-pixel impulse noise in X-ray images. A multi-pixel impulse is understood as a set of several neighboring pixels, the intensity of each significantly exceeds background intensity. Multi-pixel noise can occur, for example, due to the blooming effect, the reason being the limited value of pixel saturation capacity. This article defines the thresholds for the intensity increment relative to the eight immediate neighbors, above which the current pixel is processed by the median filter. The dependence of these thresholds on the number of pixels in an impulse is presented. The proposed algorithm is based on the median filtering process, which consists of several iterations. In this case, the filter has the smallest possible size, which minimizes image distortion during processing. In particular, to exclude a single-pixel impulse, pixel processing is turned on when intensity surge exceeds 3.5 with the grayscale value ranging from 0 to 1. At the same time, to exclude nine-pixel impulses, three iterations are required with the following thresholds: the first iteration with a threshold 2.0; the second iteration also with a threshold 2.0 and the third iteration with a threshold 3.5. The algorithm proposed was tested on real X-ray images corrupted by multi-pixel impulse noise. The algorithm is not only simple, but also reliable and suitable for real-time implementation and application. The efficiency of the technique is shown in comparison with other known filtering methods with respect to the degree of noise suppression. The main result of the testing is that only the proposed method allows excluding multi-pixel noise. Other advantage of the algorithm is its weak effect on the level of Gaussian noise leading to the absence of image blurring (or preserving image details) during processing.

Silhouettes analysis: a posthuman method for visualizing and examining the material world

2021 ◽  
pp. 146879412199901
Author(s):  
Grit Höppner
Keyword(s):  
Image Analysis ◽  
Old Age ◽  
Qualitative Inquiry ◽  
Material World ◽  
Agential Realism ◽  
The Social ◽  
Alienation Effect ◽  
Classical Image ◽  
Human Actors ◽  
Image Details

In recent decades, postmodern, poststructuralist, and social constructivist theories, and the methodologies and methods they have informed, have been criticized for focusing primarily on human actors, discourses, and actions. Simultaneously, so-called posthuman theories have been developed that decentralize the human, reject an unquestioned use of the dualism of human/nonhuman, and emphasize the importance of the material world in the production of the social. A key concern for current qualitative inquiry is to develop methods that contribute to the critique of human-centered analysis. In this article, I explore what we learn about the material world when we do not use verbal methods or written data but image details of moveable formations, which are made into silhouettes using Karen Barad’s agential realism. After introducing posthuman methodology I perform a silhouettes analysis focusing on old age. The intention is to demonstrate that silhouettes analysis makes it possible to gain new insights into the features of materialities of old age in a way that classical image analysis would not allow. In addition, silhouettes analysis produces an alienation effect that disturbs practiced viewing habits and assumptions, and can thus serve as a research tool promoting reflection. I conclude with a discussion of the advantages and limitations of silhouettes analysis for gerontological and posthuman research.

Preliminary study of improved median filter using adaptively mask size in light microscopic image

Microscopy ◽  
2020 ◽  
Vol 69 (1) ◽  
pp. 31-36
Author(s):  
Ji-Youn Kim ◽  
Youngjin Lee
Keyword(s):  
Image Quality ◽  
Coefficient Of Variation ◽  
Signal To Noise Ratio ◽  
Median Filter ◽  
Microscopic Image ◽  
Signal To Noise ◽  
Mask Size ◽  
Preliminary Study ◽  
Noise Ratio ◽  
Image Details

Abstract This study aimed to develop and evaluate an improved median filter (IMF) with an adaptive mask size for light microscope (LM) images. We acquired images of the mouse first molar using a LM at 100× magnification. The images obtained using our proposed IMF were compared with those from a conventional median filter. Several parameters such as the contrast-to-noise ratio, coefficient of variation, no-reference assessments and peak signal-to-noise ratio were employed to evaluate the image quality quantitatively. The results demonstrated that the proposed IMF could effectively de-noise the LM images and preserve the image details, achieving a better performance than the conventional median filter.

scholarly journals An Image Copy-Move Forgery Detection Scheme Based on A-KAZE and SURF Features

Symmetry ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 706 ◽  
Author(s):  
Chengyou Wang ◽  
Zhi Zhang ◽  
Xiao Zhou
Keyword(s):  
Feature Detection ◽  
Joint Photographic Expert Group ◽  
Social Stability ◽  
Forgery Detection ◽  
Detection Scheme ◽  
Speeded Up Robust Features ◽  
Image Blurring ◽  
Surf Features ◽  
Copy Move Forgery Detection ◽  
Processing Techniques

The popularity of image editing software has made it increasingly easy to alter the content of images. These alterations threaten the authenticity and integrity of images, causing misjudgments and possibly even affecting social stability. The copy-move technique is one of the most commonly used approaches for manipulating images. As a defense, the image forensics technique has become popular for judging whether a picture has been tampered with via copy-move, splicing, or other forgery techniques. In this paper, a scheme based on accelerated-KAZE (A-KAZE) and speeded-up robust features (SURF) is proposed for image copy-move forgery detection (CMFD). It is difficult for most keypoint-based CMFD methods to obtain sufficient points in smooth regions. To remedy this defect, the response thresholds for the A-KAZE and SURF feature detection stages are set to small values in the proposed method. In addition, a new correlation coefficient map is presented, in which the duplicated regions are demarcated, combining filtering and mathematical morphology operations. Numerous experiments are conducted to demonstrate the effectiveness of the proposed method in searching for duplicated regions and its robustness against distortions and post-processing techniques, such as noise addition, rotation, scaling, image blurring, joint photographic expert group (JPEG) compression, and hybrid image manipulation. The experimental results demonstrate that the performance of the proposed scheme is superior to that of other tested CMFD methods.

scholarly journals From Insect Vision to a Novel Bio-Inspired Algorithm for Image Denoising

2020 ◽  
Author(s):  
Manfred Hartbauer
Keyword(s):  
Image Denoising ◽  
Color Images ◽  
Insect Vision ◽  
Night Vision ◽  
Primitive Type ◽  
Noise Estimate ◽  
Local Means ◽  
Static Images ◽  
Image Details ◽  
Novel Algorithm

Night active insects inspired the development of image enhancement methods that uncover the information contained in dim images or movies. Here, I describe a novel bionic night vision (NV) algorithm that operates in the spatial domain to remove noise from static images. The parameters of this NV algorithm can be automatically derived from global image statistics and a primitive type of noise estimate. In a first step, luminance values were ln-transformed, and then adaptive local means’ calculations were executed to remove the remaining noise without degrading fine image details and object contours. Its performance is comparable with several popular denoising methods and can be applied to grey-scale and color images. This novel algorithm can be executed in parallel at the level of pixels on programmable hardware.

scholarly journals ERDBNet: Enhanced Residual Dense Block Net --A New Net to Rich ESRGAN Image Details

2021 ◽  
Vol 2083 (4) ◽  
pp. 042026
Author(s):  
Lizhuo Gao
Keyword(s):  
Digital Image ◽  
Super Resolution ◽  
Original Structure ◽  
Low Resolution ◽  
Residual Structure ◽  
Starting Point ◽  
Image Details ◽  
Trained Network ◽  
Low Resolution Images

Abstract Super resolution is applied in many digital image fields. In many cases, only a set of low-resolution images can be obtained, but the image needs a higher resolution, and then SR needs to be applied. SR technology has undergone years of development. Among them, SRGAN is the key work to introduce GAN into the SR field, which can truly restore a large number of details on the basis of low-pixel pictures. ESRGAN is a further improvement on SRGAN. By removing the BN layer in SRGAN, the effect of artifacts in SRGAN is eliminated. However, there is still a problem that the restoration of information on small and medium scales is not accurate enough. The proposed ERDBNet improve the model on the basis of ESRGAN, and use the ERDB block to replace the original RRDB block. The new structure uses a three-layer dense block to replace the original dense block, and a residual structure of the starting point is added to each dense block. The pre-trained network can reach a PSNR of 30.425 after 200k iterations, and the minimum floating PSNR is only 30.213. Compared with the original structure, it is more stable and performs better in the detail recovery of many low-pixel images.

scholarly journals An Analysis of the Optical System of a Length Measurement Comparator

Mechanika ◽  
2020 ◽  
Vol 26 (6) ◽  
pp. 518-525
Author(s):  
Rimantas LAZDINAS ◽  
Mindaugas JUREVICIUS ◽  
Vladas VEKTERIS ◽  
Vytautas TURLA ◽  
Eugenijus JURKONIS
Keyword(s):  
Optical System ◽  
Processing Speed ◽  
Length Measurement ◽  
Identification Algorithm ◽  
High Processing Speed ◽  
Image Blurring ◽  
Scale Calibration ◽  
Calibration Accuracy ◽  
The Impact ◽  
High Processing

In the paper, the optical system of a precise bar length measuring comparator is analysed. The requirements for such a system are determined and systematized. The impact of the resolution, signal discretization frequency, image blurring, bar edge measurement indeterminacy and camera noise on measuring the bar width and establishing the bar position is discussed upon. Various algorithms have been analysed and finally a bar edge identification algorithm oriented to the scale calibration accuracy and the high processing speed was proposed. In the end of the paper, conclusions are provided.

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