Cardei, V. C., Funt, B., & Barnard, K. (2002). Estimating the scene illumination chromaticity by using a neural network. Journal of the Optical Society of America A: Optics and Image Science, and Vision, 19(12), 2374-2386.
PMID: 12469731;Abstract:
A neural network can learn color constancy, defined here as the ability to estimate the chromaticity of a scene's overall illumination. We describe a multilayer neural network that is able to recover the illumination chromaticity given only an image of the scene. The network is previously trained by being presented with a set of images of scenes and the chromaticities of the corresponding scene illuminants. Experiments with real images show that the network performs better than previous color constancy methods. In particular, the performance is better for images with a relatively small number of distinct colors. The method has application to machine vision problems such as object recognition, where illumination-independent color descriptors are required, and in digital photography, where uncontrolled scene illumination can create an unwanted color cast in a photograph. © 2002 Optical Society of America.
Schlecht, J., Barnard, K., Spriggs, E., & Pryor, B. (2007). Inferring grammar-based structure models from 3D microscopy data. Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition.
Abstract:
We present a new method to fit grammar-based stochastic models for biological structure to stacks of microscopic images captured at incremental focal lengths. Providing the ability to quantitatively represent structure and automatically fit it to image data enables important biological research. We consider the case where individuals can be represented as an instance of a stochastic grammar, similar to L-systems used in graphics to produce realistic plant models. In particular, we construct a stochastic grammar of Alternaria, a genus of fungus, and fit instances of it to microscopic image stacks. We express the image data as the result of a generative process composed of the underlying probabilistic structure model together with the parameters of the imaging system. Fitting the model then becomes probabilistic inference. For this we create a reversible-jump MCMC sampler to traverse the parameter space. We observe that incorporating spatial structure helps fit the model parts, and that simultaneously fitting the imaging system is also very helpful. © 2007 IEEE.
Morris, S., Morris, A., & Barnard, K. (2004). Digital trail libraries. Proceedings of the ACM IEEE International Conference on Digital Libraries, JCDL 2004, 63-71.
Abstract:
We propose the idea of an online, user submitted digital library of recreation trails. Digital libraries of trails offer advantages over paper guidebooks in that they are more accurate, dynamic and not limited to the experience of the author(s). The basic representation of a trail is a GPS track log, recorded as recreators travel on trails. As users complete trips, the GPS track logs of their trips are submitted to the central library voluntarily. A major problem is that track logs will overlap and intersect each other. We present a method for the combination of overlapping and intersecting GPS track logs to create a network of GPS trails. Each trail segment in the network can then be characterized by automatic and manual means, producing a digital library of trails. We also describe the TopoFusion system which creates, manages and visualizes GPS data, including GPS networks.
Savage, R., Palafox, L. F., Morrison, C. T., Rodriguez, J. J., Barnard, K. J., Byrne, S., & Hamilton, C. W. (2018). A Bayesian Approach to Sub-Kilometer Crater Shape Analysis using Individual HiRISE Images. Transactions on Geoscience and Remote Sensing.
Funt, B., Cardei, V., & Barnard, K. (1997). Learning color constancy. Proceedings of the Color Imaging Conference: Color Science, Systems, and Applications, 58-60.
Abstract:
We decided to test a surprisingly simple hypothesis; namely, that the relationship between an image of a scene and the chromaticity of scene illumination could be learned by a neural network. The thought was that if this relationship could be extracted by a neural network, then the trained network would be able to determine a scene's Illuminant from its image, which would then allow correction of the image colors to those relative to a standard illuminance, thereby providing color constancy. Using a database of surface reflectances and illuminants, along with the spectral sensitivity functions of our camera, we generated thousands of images of randomly selected illuminants lighting `scenes' of 1 to 60 randomly selected reflectances. During the learning phase the network is provided the image data along with the chromaticity of its illuminant. After training, the network outputs (very quickly) the chromaticity of the illumination given only the image data. We obtained surprisingly good estimates of the ambient illumination lighting from the network even when applied to scenes in our lab that were completely unrelated to the training data.
