Improving source camera identification using a simplified total variation based noise removal algorithm

In this paper a new method for photo-response non-uniformity (PRNU) noise extraction is proposed. Photo-response non-uniformity noise patterns are a reliably method for digital camera identification. Especially with a large number of images the process of camera identification can be time consuming. The proposed method aims to increase the speed of PRNU extraction without losing accuracy when compared to the state-of-the-art method. Currently wavelet based denoising is used as the standard for PRNU extraction. Our proposed method is based on a simplified version of the Total Variation based noise removal algorithm. Results show that extraction is about 3.5 times faster with our method than with the wavelet based denoising algorithm. While initially only an increase in speed was the goal, results indicate that the Total Variation based noise removal algorithm is not only faster, but also more accurate than the state-of-the-art method

Improving source camera identification using a simplified total variation based noise removal algorithm

In this paper a new method for photo-response non-uniformity (PRNU) noise extraction is proposed. Photo-response non-uniformity noise patterns are a reliably method for digital camera identification. Especially with a large number of images the process of camera identification can be time consuming. The proposed method aims to increase the speed of PRNU extraction without losing accuracy when compared to the state-of-the-art method. Currently wavelet based denoising is used as the standard for PRNU extraction. Our proposed method is based on a simplified version of the Total Variation based noise removal algorithm. Results show that extraction is about 3.5 times faster with our method than with the wavelet based denoising algorithm. While initially only an increase in speed was the goal, results indicate that the Total Variation based noise removal algorithm is not only faster, but also more accurate than the state-of-the-art method

Common source identification of images in large databases

Photo-response non-uniformity noise patterns are a robust way to identify the source of an image. However, identifying a common source of images in a large database may be impractical due to long computation times. In this paper a solution for large volume digital camera identification is proposed, which combines, and sometimes slightly modifies, existing methods for a 500 times improvement in the speed of common source identification. Single image comparisons are often plagued by considerable noise contamination from scene content and random noise, which makes it harder to accomplish reliable common source identification. Therefore a new method is introduced that can increase true positive rates by more than 45% at very low computation costs. Analysis of real data from a fraud case shows the effectiveness of the proposed method. As a whole the proposed solution makes it possible to analyze a large database in forensically relevant time, without resorting to large and expensive computer clusters

A review of acoustic imaging methods using phased microphone arrays: Part of the “Aircraft Noise Generation and Assessment” Special Issue

Phased microphone arrays have become a well-established tool for performing aeroacoustic measurements in wind tunnels (both open-jet and closed-section), flying aircraft, and engine test beds. This paper provides a review of the most well-known and state-of-the-art acoustic imaging methods and recommendations on when to use them. Several exemplary results showing the performance of most methods in aeroacoustic applications are included. This manuscript provides a general introduction to aeroacoustic measurements for non-experienced microphone-array users as well as a broad overview for general aeroacoustic experts.Aircraft Noise and Climate Effect

Integration methods for distributed sound sources

Most acoustic imaging methods assume the presence of point sound sources and, hence, may fail to correctly estimate the sound emissions of distributed sound sources, such as trailing-edge noise. In this contribution, three integration techniques are suggested to overcome this issue based on models considering a single point source, a line source, and several line sources, respectively. Two simulated benchmark cases featuring distributed sound sources are employed to compare the performance of these integration techniques with respect to other well-known acoustic imaging methods. The considered integration methods provide the best performance in retrieving the source levels and require short computation times. In addition, the negative effects of the presence of unwanted noise sources, such as corner sources in wind-tunnel measurements, can be eliminated. A sensitivity analysis shows that the integration technique based on a line source is robust with respect to the choice of the integration area (shape, position, and mesh fineness). This technique is applied to a trailing-edge-noise experiment in an open-jet wind tunnel featuring a NACA 0018 airfoil. The location and far-field noise emissions of the trailing-edge line source were calculated.Aircraft Noise and Climate EffectsAerospace Engineerin

Connecting Our Stories. Inclusion Matters

The Lectorate of Inclusive Education had its official start at the inaugural speech by Aminata Cairo on January 17, 2018. Since then a team of dedicated people have given shape and form to the lectorate. Some have come and gone since then, each contributing in their own way. Inclusive Education is an elusive term. It is not clear-cut and many people do not know what it means. Inherently it is linked to diversity issues, which have become associated with "having to deal with the other", discrimination, exclusion, and more of such bothersome issues. Inclusion is about doing it however, about making it happen. Inclusive education is about creating optimal learning opportunities to accommodate students of all backgrounds, but requires dealing with those difficult issues. The language is not available, the level of comfort is not available, and so here is a whole lectorate dedicated to dealing with this pesky implication that somehow we are not doing something right. That is one way of looking at it. There is some truth in that as well. As successful as our educational systems have been throughout hundreds of years, we now acknowledge that it has not been successful for all who attempt to partake and not necessarily due to their lack of effort. So, somehow we have fallen short. Who wants to talk about that? We need to talk about that, but how? We need to have the sensitivity that the conversation might be difficult and complex. We need to acknowledge that the conversation might require us to open up and be vulnerable. We need to be brave, but the conversation must happen. In this volume the members of the knowledge circle and student branch have taken a first step. The assignment was to write about their involvement with the lectorate, but to share where their passion came from. There is a reason why you are so passionate about this (difficult) topic, something about your story that drives you to want to do this. Share that. It was not an easy task for all, even if only in one paragraph. After all, it requires one to open a window into one's soul. We cannot expect and lead people into the difficult conversations if we are not willing to lead by example. As you will see, they lived up to the task. Hoping that our first step will be an inspiration for you to take the next

A review of acoustic imaging methods using phased microphone arrays

Phased microphone arrays have become a well-established tool for performing aeroacoustic measurements in wind tunnels (both open-jet and closed-section), flying aircraft, and engine test beds. This paper provides a review of the most wellknown and state-of-the-art acoustic imaging methods and recommendations on when to use them. Several exemplary results showing the performance of most methods in aeroacoustic applications are included. This manuscript provides a general introduction to aeroacoustic measurements for non-experienced microphone-array users as well as a broad overview for general aeroacoustic experts