Detection of features in images
First Claim
1. A method of detecting features-of-interest in an image, comprising the steps of:
- making an intensity independent comparison of the image intensity profile with a shape model for predefined features of interest; and
storing for the profile a label comprising the level of similarity to the shape model.
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Abstract
An image processing technique which identifies pixels in images which are associated with features having a selected shape, such as but not exclusively step edge, roof, ridge or valley. The shape of the intensity profile in the image is compared in an intensity independent way with a shape model to select those pixels which satisfy the shape model and are thus associated with the feature of interest. This comparison is achieved by examining the phase and amplitude of a spectral decomposition of parts of the image profile in the spatial or spatio temporal frequency domain. This decomposition can be achieved using quadrature wavelet pairs such as log-Gabor wavelets. The difference between the odd and even components, known as the feature asymmetry, gives an indication of the shape of the feature. The analysis may be extended to the time domain by looking at the shape of the image profile across a time sequence of images, which gives an indication of the velocity of a moving feature. Pixels identified as belonging to a feature of the right shape are labelled with the value of feature asymmetry, the local amplitude, feature orientation and feature velocity, and this information can be used to improve the tracking of detected features through a sequence of images.
112 Citations
24 Claims
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1. A method of detecting features-of-interest in an image, comprising the steps of:
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making an intensity independent comparison of the image intensity profile with a shape model for predefined features of interest; and
storing for the profile a label comprising the level of similarity to the shape model. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification