Furthermore, the driver’s kinematic motion model allows one to implement an extended Kalman filter that simplifies the tracking of the points in the image space (only the five pose angles need to be estimated with the filter, instead of applying a filter to each of the salient points in the image). Final
The publication of the pioneering work of Yablonovitch [1] and John [2] in 1987 may have started the intensive studies on photonic crystals (PCs) and sparked much of the modern interest in this field. PCs are materials that possess a periodic refractive index variance and have become a subject of high interest within the materials science community [3,4]. Due to the periodicity in dielectric materials, PC materials possess a photonic band gap (PBG), forbidding certain wavelengths of light located in the PBG from transmission through the material [5].

According to variations in the refractive index and period in space, PCs can be classified as one-dimensional (1D), two-dimensional (2D) and three-dimensional (3D). They have been intensively used in the area of optical fibers, photovoltaic devices, Bragg mirrors, displays, sensors and so on [3,4,6,7].Recently, PCs have increasingly attracted the interest of researchers due to their unique structural color properties [7]. Photonic materials with vivid structural colors exist commonly in Nature, and are found in species of birds, butterflies, insects, marine life, and even flora [7�C27]. Many organisms have the ability to tune their structural colors in response to surrounding environment for camouflage, warning about enemies or communication [7].

Inspired by these biological displays from Nature, PCs have been developed as chromotropic materials for colorimetric sensors. The sensors are created by combining materials that are responsive to external stimuli [28] such as solvents [29�C33], vapors [34�C38], temperature [39�C46], ionic strength and pH [47�C53], biomolecules [54�C61], mechanical force [62�C66] and so on. Colorimetric sensors are able to transduce environmental changes into visual color changes and are well-suited to the realization of low-cost and low-power sensors [34]. They provide an intuitively simple yet powerful detection mechanism based on the presence of PBGs that forbid the propagation of certain wavelengths of light in the visible range, negating the need for extra detectors by making environmental changes visible to the unaided eye.

In order to satisfy the increasing number of requirements for actual application of colorimetric sensors, it is critical to develop smart artificial photonic materials with excellent sensitivity, response rate, durability and selectivity. The inspiration for the design and construction of photonic structures with vivid structural colors is extensively Batimastat borrowed from nature and naturally occurring systems.