Unexpected Artifacts in a Digital Photograph

2011 ◽  
pp. 211-223
Author(s):  
Matthew J. Sorell
Keyword(s):  
Image Enhancement ◽  
Football Player ◽  
Jpeg Compression ◽  
Digital Photograph ◽  
Image Tampering ◽  
Unexpected Phenomenon

This chapter investigates an unexpected phenomenon observed in a recent digital photograph, in which the logo of a non-sponsoring sports company appears on the jersey of a famous football player in just one of a sequence of images. After eliminating deliberate image tampering as a cause, a hypothetical sequence of circumstances is proposed, concerning the lighting, dominant colours, infrared sensitivity, optical pre-processing, image enhancement and JPEG compression. The hypotheses are tested using a digital SLR camera. The investigation is of interest in a forensic context, firstly as a possible explanation in case such a photograph is observed, and secondly to be able to confirm or refute claims of such artifacts put forward claiming that a hypothetical image is not really what it claims to be.

scholarly journals Double JPEG Compression Detection Based on Noise-Free DCT Coefficients Mixture Histogram Model

Symmetry ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1119 ◽  
Author(s):  
Nan Zhu ◽  
Junge Shen ◽  
Xiaotong Niu
Keyword(s):  
Posterior Probability ◽  
Detection Method ◽  
Jpeg Compression ◽  
Quantization Noise ◽  
Image Tampering ◽  
Double Jpeg Compression ◽  
Dct Coefficients ◽  
Transform Coefficients ◽  
Image Tampering Detection ◽  
Jpeg Image Compression

With the wide use of various image altering tools, digital image manipulation becomes very convenient and easy, which makes the detection of image originality and authenticity significant. Among various image tampering detection tools, double JPEG image compression detector, which is not sensitive to specific image tampering operation, has received large attention. In this paper, we propose an improved double JPEG compression detection method based on noise-free DCT (Discrete Cosine Transform) coefficients mixture histogram model. Specifically, we first extract the block-wise DCT coefficients histogram and eliminate the quantization noise which introduced by rounding and truncation operations. Then, for each DCT frequency, a posterior probability can be obtained by solving the DCT coefficients mixture histogram with a simplified model. Finally, the probabilities from all the DCT frequencies are accumulated to give the posterior probability of a DCT block being authentic or tampered. Extensive experimental results in both quantitative and qualitative terms prove the superiority of our proposed method when compared with the state-of-the-art methods.

Exploring Coronal Structures with SOHO

2000 ◽  
Vol 179 ◽  
pp. 403-406
Author(s):  
M. Karovska ◽  
B. Wood ◽  
J. Chen ◽  
J. Cook ◽  
R. Howard
Keyword(s):  
Solar Corona ◽  
Image Enhancement ◽  
Coronal Mass Ejections ◽  
Dynamical Evolution ◽  
Small Scale ◽  
Low Contrast ◽  
Contrast Structures ◽  
Scale Structures ◽  
Small Scale Structures ◽  
Coronal Structures

AbstractWe applied advanced image enhancement techniques to explore in detail the characteristics of the small-scale structures and/or the low contrast structures in several Coronal Mass Ejections (CMEs) observed by SOHO. We highlight here the results from our studies of the morphology and dynamical evolution of CME structures in the solar corona using two instruments on board SOHO: LASCO and EIT.

Image Enhancement in 26GHz-Band 1-Bit Direct Digital RF Transmitter Using Manchester Coding

2020 ◽  
Author(s):  
Junhao ZHANG ◽  
Masafumi KAZUNO ◽  
Mizuki MOTOYOSHI ◽  
Suguru KAMEDA ◽  
Noriharu SUEMATSU
Keyword(s):  
Image Enhancement ◽  
Rf Transmitter ◽  
Digital Rf ◽  
Manchester Coding

Deep-STRESS Capsule Video Endoscopy Image Enhancement

2018 ◽  
Vol 2018 (1) ◽  
pp. 247-252
Author(s):  
Ahmed Mohammed ◽  
Marius Pedersen ◽  
Øistein Hovde ◽  
Sule Yildirim
Keyword(s):  
Image Enhancement ◽  
Video Endoscopy
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