Journal ArticleDOI
Theory of Edge Detection
David Marr,Ellen C. Hildreth +1 more
TLDR
The theory of edge detection explains several basic psychophysical findings, and the operation of forming oriented zero-crossing segments from the output of centre-surround ∇2G filters acting on the image forms the basis for a physiological model of simple cells.Abstract:
A theory of edge detection is presented. The analysis proceeds in two parts. (1) Intensity changes, which occur in a natural image over a wide range of scales, are detected separately at different scales. An appropriate filter for this purpose at a given scale is found to be the second derivative of a Gaussian, and it is shown that, provided some simple conditions are satisfied, these primary filters need not be orientation-dependent. Thus, intensity changes at a given scale are best detected by finding the zero values of delta 2G(x,y)*I(x,y) for image I, where G(x,y) is a two-dimensional Gaussian distribution and delta 2 is the Laplacian. The intensity changes thus discovered in each of the channels are then represented by oriented primitives called zero-crossing segments, and evidence is given that this representation is complete. (2) Intensity changes in images arise from surface discontinuities or from reflectance or illumination boundaries, and these all have the property that they are spatially. Because of this, the zero-crossing segments from the different channels are not independent, and rules are deduced for combining them into a description of the image. This description is called the raw primal sketch. The theory explains several basic psychophysical findings, and the operation of forming oriented zero-crossing segments from the output of centre-surround delta 2G filters acting on the image forms the basis for a physiological model of simple cells (see Marr & Ullman 1979).read more
Citations
More filters
Journal ArticleDOI
Optimal Edge Detector Design I: Parameter Selection and Noise Effects
TL;DR: This paper comments on the optimality of the Laplacian of a Gaussian edge detection filter which localizes edges through zero crossings in the filtered image by applying the filter to two ideal periodic edge models blurred by aGaussian distribution point-spread function.
Journal ArticleDOI
Multidirectional and multiscale edge detection via M-band wavelet transform
TL;DR: In this correspondence, the problem of directional and multiscale edge detection is considered and with the application of the Teager's energy operator at the analysis stage, it is possible to obtain a reduction in unwanted zero-crossings.
Journal ArticleDOI
Delineation of agricultural fields in smallholder farms from satellite images using fully convolutional networks and combinatorial grouping.
TL;DR: This article introduces a strategy to detect field boundaries using a fully convolutional network in combination with a globalisation and grouping algorithm that shows promising results by automatically delineating field boundaries with F-scores higher than 0.7 and 0.6.
Journal ArticleDOI
The spatial region of integration for visual symmetry detection
TL;DR: The size and shape of this integration region (IR) is investigated by measuring human detection of spatially band–pass symmetrical patches embedded in noise by showing resistance to disruption of symmetry improves with increasing patch size, and then asymptotes when the embedded region fills the IR.
Journal ArticleDOI
Knowledge-directed vision: control, learning, and integration
TL;DR: It is argued that knowledge-directed vision systems typically failed for two reasons: inadequate vision procedures and the lack of a control formalism blocked their further development.
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Application of fourier analysis to the visibility of gratings
F. W. Campbell,John G. Robson +1 more
TL;DR: The contrast thresholds of a variety of grating patterns have been measured over a wide range of spatial frequencies and the results show clear patterns of uniformity in the response to grating noise.