Searching for ’s Ark: Analysing the Ararat Anomaly

Francois Luus and Prof Sunil Maharaj

Computational intelligence is used to objectively evaluate

textural uniqueness in remotely sensed anomalies and to discover

characteristics that can assist in identifying underlying artefacts.

The Ararat Anomaly, a possible landing site of the Biblical Noah’s

Ark on in Turkey, was investigated with this

methodology in a specially commandeered QuickBird satellite

image.

FEATURES 57 INNOVATE 9 2014  Figure 1: QuickBird February 2003 image of the Ararat Anomaly (left), © 2014 DigitalGlobe Inc., and an illustration of the dominant Gabor wavelet filter responses (right).

The data used in this study is one of local regions in the image. Maximal magnitude reflecting the amount the best available remote sensing shadow and highlight protection of variation accounted for by the images of the anomaly. This image was used to recover all the fine dimension. is a panchromatic QuickBird electro- detail in the shadows and highlights optical image that was acquired in of the image. Maximum detail In unsupervised clustering, such a February 2003. enhancement with independent similarity measure is used to group detail processing was also used, very similar features together in The objective of this study is to without any detail boost to prevent a unique cluster, and different quantify the novelty of textures on the exaggeration of details. clusters are distinguished only as a the anomaly, at least in terms of the result of the initial grouping based textures found in the surrounding Textural uniqueness on the similarity measure. area. This data can provide a more objective starting point for further Textural uniqueness is a scalar To measure relative dissimilarity analysis of the anomaly and could measurement that indicates the with an Euclidean distance measure possibly serve as supporting relative scarcity or probability of a does not guarantee that textures evidence of an artefact underlying particular texture occurring relative found to be unique will be well the anomaly, which is covered by to a set of available textures. defined or interesting in terms of glacial ice. the intended application. This measurement can be used in This textural uniqueness measure an unsupervised manner to detect Gabor texture features is an important contribution and indicate novel textures in in detailed remote sensing remote sensing imagery, such as Gabor wavelet filter features have analysis, since it describes a the Ararat Anomaly images. In this been used to incorporate a relative low computational complexity way, machine intelligence can find measure of texture prominence implementation that emphasises interesting parts of the anomaly. in the uniqueness search. Linear the uniqueness of prominent and Gabor filters model the visual useful texture components. The The uniqueness measurement is cortex of mammalian brains and original QuickBird February 2003 only relative and it is subject to the are used for edge detection. panchromatic acquisition of the way in which texture and texture Ararat Anomaly is shown in similarity are defined. A filter response with a relatively Figure 1. large magnitude indicates a more The similarity of two texture well-defined and prominent texture Topaz Adjust 5 image-enhancing features can be measured by and a set of filters is used to cover software was used to enhance the taking the Euclidean distance all edge orientations and scales. original with standard brightness between the two features in This results in a feature vector that increase and adaptive exposure the multidimensional feature is automatically categorised in a maximisation with minimum region space, after preprocessing each manner that makes sense to human size, which balance the exposure of feature dimension to have a range visual perception.

FEATURES 58 INNOVATE 9 2014 A depiction of the dominant filter responses is given in Figure 1. The hue describes the dominant orientation, the saturation describes the response magnitude and the intensity value gives the dominant scale for each texture centred at each pixel.

A larger Euclidean distance between two Gabor texture features means that there is likely to be more prominence and novelty in one of the textures. The Gabor wavelet scales were selected by measuring the total response energy at different scales and including the appropriate scale range for the  Figure 2: Twelve unique textures found in the enhanced QuickBird February given image. 2003 image of the Ararat Anomaly.

The exact wavelets that have itself, which involve larger unique been used for this study include wavelet combinations centred at seven different scales, each with the detected points of uniqueness. 32 different orientations to obtain If the textural uniqueness was 224 Gabor feature dimensions. evaluated over an even larger The feature dimensions are left image, the probability of the unscaled to preserve relative occurrence of an overall uniqueness response magnitudes over different would be proportionally reduced, scales to favour higher energy given an approximately equal scales. textural coverage profile. Unique textures Further study may consider the locations pinpointed by the Locality-sensitive hashing was uniqueness search to ascertain used to efficiently approximate Prof Sunil Maharaj is the new whether there might be clues that the nearest neighbours, or most Dean of the Faculty of Engineering, can give credence to an artefact similar textures, for every texture Built Environment and Information underlying the anomaly. descriptor vector centred at every Technology at the University of Pretoria, image pixel. former Head of the Department of Acknowledgements Electrical, Electronic and Computer By obtaining the most similar Engineering and holder of the textures for every texture, the The authors would like to Sentech Chair in Broadband Wireless relative uniqueness of the particular acknowledge Prof Porcher L Multimedia Communications (BWMC). texture can be measured as the Taylor III from the University of average of the Euclidean distances Richmond for introducing them to the nearest neighbours. Locality- to the problem and for utilising sensitive hashing with eight-dot their methods in the news articles products per hash, 40 independent that headlined on Space.com, projections and quantisation bin Discovery.com, as well as the widths of 0.001 is used. science pages of Yahoo and Fox News. Prof Taylor is the lead The most unique textures found on investigator of the Ararat Anomaly. the anomaly are shown in Figure 2, which includes 12 texture patches The authors also acknowledge that could be considered novel in a DigitalGlobe, a leading commercial Gabor feature sense, relative to a vendor of space imagery and large range of different textures as geospatial content, as well as an provided by the surrounding image. operator of civilian remote sensing Francois Luus is a PhD candidate at spacecraft. DigitalGlobe has flown the University of Pretoria. His research There are a number of unique numerous missions over the interests include remote sensing and texture points on the anomaly anomaly on Prof Taylor’s request. artificial intelligence.

FEATURES 59 INNOVATE 9 2014