Journal•ISSN: 0016-0032
Journal of The Franklin Institute-engineering and Applied Mathematics
About: Journal of The Franklin Institute-engineering and Applied Mathematics is an academic journal. The journal publishes majorly in the area(s): Control theory & Nonlinear system. It has an ISSN identifier of 0016-0032. Over the lifetime, 11690 publication(s) have been published receiving 167409 citation(s).
Papers published on a yearly basis
Papers
More filters
7,100 citations
6,600 citations
TL;DR: In this article, a comprehensive mathematical model to account for colour constancy is formulated, where the visual system is able to measure true object colour in complex scenes under a broad range of spectral compositions, for the illumination; it is assumed that the visual systems must implicitly estimate and illuminant.
Abstract: A comprehensive mathematical model to account for colour constancy is formulated. Since the visual system is able to measure true object colour in complex scenes under a broad range of spectral compositions, for the illumination; it is assumed that the visual system must implicitly estimate and illuminant. The basic hypothesis is that the estimate of the illuminant is made on the basis of spatial information from the entire visual field. This estimate is then used by the visual system to arrive at an estimate of the (object) reflectance of the various subfields in the complex visual scene. The estimates are made by matching the inputs to the system to linear combinations of fixed bases and standards in the colour space. The model provides a general unified mathematical framework for related psychophysical phenomenology.
1,348 citations
1,068 citations
TL;DR: In this article, the authors considered the problem of matching an arbitrary load impedance to a pure resistance by means of a reactive network and derived necessary and sufficient conditions for the physical realizability of a function of frequency representing the input reflection coefficient of a matching network terminated in a prescribed load impedance.
Abstract: This paper deals with the general problem of matching an arbitrary load impedance to a pure resistance by means of a reactive network. It consists primarily of a systematic study of the origin and nature of the theoretical limitations on the tolerance and bandwidth of match and of their dependence on the characteristics of the given load impedance. Necessary and sufficient conditions are derived for the physical realizability of a function of frequency representing the input reflection coefficient of a matching network terminated in a prescribed load impedance. These conditions of physical realizability are then transformed into a set of integral relations involving the logarithm of the magnitude of the reflection coefficient. Such relations are particularly suitable for the study of the limitations on the bandwidth and tolerance of match. Definite expressions for these quantities are obtained in special cases. The practical problem of approaching the optimum theoretical tolerance by means of a network with a finite number of elements is also considered. Design curves are provided for a particularly simple but very important type of load impedance. In addition, a very convenient method is presented for computing the values of the elements of the resulting matching network.
840 citations