Examples of image blurring

2021 ◽  
pp. 15-48
Author(s):  
Mario Bertero ◽  
Patrizia Boccacci ◽  
Christine De MoI
Keyword(s):  
Symmetry ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 706 ◽  
Author(s):  
Chengyou Wang ◽  
Zhi Zhang ◽  
Xiao Zhou

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.


Mechanika ◽  
2020 ◽  
Vol 26 (6) ◽  
pp. 518-525
Author(s):  
Rimantas LAZDINAS ◽  
Mindaugas JUREVICIUS ◽  
Vladas VEKTERIS ◽  
Vytautas TURLA ◽  
Eugenijus JURKONIS

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.


2015 ◽  
Vol 781 ◽  
pp. 543-546
Author(s):  
Piyanart Chotikawanid ◽  
Kharittha Thongkor ◽  
Thumrongrat Amornraksa

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.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
A. B. Mikhalychev ◽  
P. I. Novik ◽  
I. L. Karuseichyk ◽  
D. A. Lyakhov ◽  
D. L. Michels ◽  
...  

AbstractQuantum imaging can beat classical resolution limits, imposed by the diffraction of light. In particular, it is known that one can reduce the image blurring and increase the achievable resolution by illuminating an object by entangled light and measuring coincidences of photons. If an n-photon entangled state is used and the nth-order correlation function is measured, the point-spread function (PSF) effectively becomes $$\sqrt{n}$$ n times narrower relatively to classical coherent imaging. Quite surprisingly, measuring n-photon correlations is not the best choice if an n-photon entangled state is available. We show that for measuring (n − 1)-photon coincidences (thus, ignoring one of the available photons), PSF can be made even narrower. This observation paves a way for a strong conditional resolution enhancement by registering one of the photons outside the imaging area. We analyze the conditions necessary for the resolution increase and propose a practical scheme, suitable for observation and exploitation of the effect.


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