PROCESS AND DEVICE FOR DETECTION OF DROPS IN A DIGITAL IMAGE AND COMPUTER PROGRAM FOR EXECUTING THIS METHOD
First Claim
Patent Images
1. A method for detection of drops appearing in a digital image acquired through a transparent wall by means of an image acquisition system, the method comprising the following steps:
- b) a gradient image is established from said digital image, by assigning to each pixel the value of the gradient at the position of the pixel;
c) said gradient image is filtered to obtain a filtered image, by assigning to each pixel a value obtained by applying a rank filter to a neighbourhood of the pixel;
d) a mask is established representing the position of the detected drops in said digital image, in which mask the pixels for which the difference between the value of the pixel in the filtered image and the value of the pixel in the gradient image exceeds a predetermined value are activated.
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Abstract
A method for detection of drops on a transparent wall through which digital images (I11-I15,I111-I115,I211-I215,I311-I315) are acquired by means of an image acquisition system, comprising the following steps:
- b) a gradient image is established from the digital image (I16) by assigning to each pixel the value of the gradient for the pixel;
- c) the gradient image is filtered by assigning to each pixel a value obtained by rank filtering;
- d) a mask representing the position of the detected drops in the digital image is established by activating the pixels for which the difference between the value of the pixel in the filtered image and the value of the pixel in the gradient image exceeds a predetermined value.
This method enables robust detection of drops in the image or the sequence of images.
Program and device for detection of drops for executing this method.
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15 Claims
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1. A method for detection of drops appearing in a digital image acquired through a transparent wall by means of an image acquisition system, the method comprising the following steps:
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b) a gradient image is established from said digital image, by assigning to each pixel the value of the gradient at the position of the pixel; c) said gradient image is filtered to obtain a filtered image, by assigning to each pixel a value obtained by applying a rank filter to a neighbourhood of the pixel; d) a mask is established representing the position of the detected drops in said digital image, in which mask the pixels for which the difference between the value of the pixel in the filtered image and the value of the pixel in the gradient image exceeds a predetermined value are activated. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification