Framing digital image credibility: image manipulation problems, perceptions and solutions

Image manipulation is subverting the credibility of photographs as a whole. Currently there is no practical solution for asserting the authenticity of a photograph. People express their concern about this when asked but continue to operate in a ‘business as usual’ fashion. While a range of digital forensic technologies has been developed to address falsification of digital photographs, such technologies begin with ‘sourceless’ images and conclude with results in equivocal terms of probability, while not addressing the meaning and content contained within the image. It is interesting that there is extensive research into computer-based image forgery detection, but very little research into how we as humans perceive, or fail to perceive, these forgeries when we view them. The survey, eye-gaze tracking experiments and neural network analysis undertaken in this research contribute to this limited pool of knowledge. The research described in this thesis investigates human perceptions of images that are manipulated and, by comparison, images that are not manipulated. The data collected, and their analyses, demonstrate that humans are poor at identifying that an image has been manipulated. I consider some of the implications of digital image manipulation, explore current approaches to image credibility, and present a potential digital image authentication framework that uses technology and tools that exploit social factors such as reputation and trust to create a framework for technologically packaging/wrapping images with social assertions of authenticity, and surfaced metadata information. The thesis is organised into 6 chapters. Chapter 1: Introduction I briefly introduce the history of photography, highlighting its importance as reportage, and discuss how it has changed from its introduction in the early 19th century to today. I discuss photo manipulation and consider how it has changed along with photography. I describe the relevant literature on the subject of image authentication and the use of eye gaze tracking and neural nets in identifying the role of human vision in image manipulation detection, and I describe my area of research within this context. Chapter 2: Literature review I describe the various types of image manipulation, giving examples, and then canvas the literature to describe the landscape of image manipulation problems and extant solutions, namely: • the nature of image manipulation, • investigations of human perceptions of image manipulation, • eye gaze tracking and manipulated images, • known efforts to create solutions to the problem of preserving unadulterated photographic representations and the meanings they hold. Finally, I position my research activities within the context of the literature. Chapter 3: The research I describe the survey and experiments I undertook to investigate attitudes toward image manipulation, research human perceptions of manipulated and unmanipulated images, and to trial elements of a new wrapper-style file format that I call .msci (mobile self-contained image), designed to address image authenticity issues. Methods, results and discussion for each element are presented in both explanatory text and by presentation of papers resulting from the experiments. Chapter 4: Analysis of eye gaze data using classification neural networks I describe pattern classifying neural network analysis applied to selected data obtained from the experiments and the insights this analysis provided into the opaque realm of cognitive perception as seen through the lens of eye gaze. Chapter 5: Discussion I synthesise and discuss the outcomes of the survey and experiments. I discuss the outcomes of this research, and consider the need for a distinction between photographs and photo art. I offer a theoretical formula within which the overall authenticity of an image can be assessed. In addition I present a potential image authentication framework built around the .msci file format, designed in consideration of my investigation of the requirements of the image manipulation problem space and the experimental work undertaken in this research. Chapter 6: Conclusions and future work This thesis concludes with a summary of the outcomes of my research, and I consider the need for future experimentation to expand on the insights gained to date. I also note some ways forward to develop an image authentication framework to address the ongoing problem of image authenticity

Optimising Peer Marking with Explicit Training: from Superficial to Deep Learning

[EN] We describe our use of formative assessment tasks measuring superficial learning as explicit training forpeer assessment of a major summative assessment task (report writing), which requires deep learning. COMP1710 at the Australian National University is a first year Web Development and Design course done by over 100 students each year, by many Computing students in their first semester of their first year or at any time prior to graduation; the course also attracts some 25% of its cohort from other academic areas of the University. We found that formative assessment trained peer markers performing a surface learning task can produce peer marks consistent with our expert summative task marker. Weaker students only demonstrating superficial learning were able to reliably assess the reports of the better students capable of the deeper learning required to produce the reports.This significantly increasesthe usefulness of peer marking, and could have use in large online courses such as MOOCs.Caldwell, S.; Gedeon, T. (2015). Optimising Peer Marking with Explicit Training: from Superficial to Deep Learning. En 1ST INTERNATIONAL CONFERENCE ON HIGHER EDUCATION ADVANCES (HEAD' 15). Editorial Universitat Politècnica de València. 626-631. https://doi.org/10.4995/HEAd15.2015.44162663

An HRD/DER-independent ER quality control mechanism involves Rsp5p-dependent ubiquitination and ER-Golgi transport

We have identified a new pathway of ER-associated degradation in Saccharomyces cerevisiae that functions separately from the HRD/DER pathway comprised of Hrd1p, Hrd3p, Der1p, and Ubc7p. This pathway, termed Hrd1p independent-proteolysis (HIP), is capable of recognizing and degrading both lumenal (CPY* and PrA*), and integral membrane proteins (Sec61–2p) that misfold in the ER. CPY* overexpression likely saturates the HRD/DER pathway and activates the HIP pathway, so the slowed degradation kinetics of CPY* in a hrd1Δ strain is restored to a wild-type rate when CPY* is overexpressed. Substrates of HIP require vesicular trafficking between the ER and Golgi apparatus before degradation by the ubiquitin-proteasome system. Ubiquitination of HIP substrates does not involve the HRD/DER pathway ubiquitin ligase Hrd1p, but instead uses another ubiquitin ligase, Rsp5p. HIP is regulated by the unfolded protein response as Ire1p is necessary for the degradation of CPY* when overexpressed, but not when CPY* is expressed at normal levels. Both the HIP and HRD/DER pathways contribute to the degradation of CPY*, and only by eliminating both is CPY* degradation completely blocked

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Pestilent error and ‘The legitimacy of skies in photographs’

I am apparently in pestilent error. Worse yet, according to Henry Peach Robinson, I may be having “a detrimental effect on the unthinking.” It appears I am a lingering member of a school of critics that for Robinson, was in 1869 “now, happily, nearly extinct.” While I would not say that I “teach that anything beyond mechanical copying or dull map-making is heresy in photography,” you all know that I believe we must distinguish between photographs (images that capture real people, places and events) and photoART (photographic images that have been enhanced or manipulated)

The Photographialist : preserving the photographical perspective

My area of research is photography, specifically photo credibility. Key to my research is the important distinction between photographs (photos of real people, places and events) and photoART (images that were once photos but have now been changed by image manipulation software). This site is a public forum to explore the art, technology and social implications of photographs, photoart and everything in between