Method for identifying marking stripes of road lanes
First Claim
1. A method, in a system for aiding the guidance of a vehicle, for identifying marking stripes demarcating at least one road lane in a road image represented by a matrix of elements each indicative of the luminosity level of an elementary portion of the image, the method comprising the steps of:
- setting a mask matrix;
determining a convolved image matrix via a convolution operation between the matrix of the road image and the mask matrix so as to identify luminosity discontinuities present in the image;
determining a binary image matrix in which each element has a first (0) or a second (1) binary value depending on the result of a comparison of a corresponding element of the convolved image matrix with a threshold value;
determining from the binary image matrix a representation of the marking stripes; and
wherein said step of setting the mask matrix includes determining a value L indicative of the number of elements of the image matrix corresponding to the width of the marking stripes wherein each row of the mask matrix comprises;
L contiguous elements having a first value;
at least one element having a value of zero being contiguous to and located on both sides of said L contiguous elements; and
a plurality of elements being contiguous to said at least one element having a value of zero and being located at the left and right ends of each row, said plurality of elements being a second value of opposite sign to said first value.
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Abstract
A method, in a system for aiding the guidance of a vehicle, for identifying marking stripes of road lanes. A road image is subjected to a convolution operation with a mask matrix so as to identify discontinuities present in the image. The resulting convolved image is compared with a threshold value and a representation of the marking stripes is determined. The mask matrix is set in such a way as to eliminate at least partially the discontinuities which do not correspond to the marking stripes.
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Citations
58 Claims
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1. A method, in a system for aiding the guidance of a vehicle, for identifying marking stripes demarcating at least one road lane in a road image represented by a matrix of elements each indicative of the luminosity level of an elementary portion of the image, the method comprising the steps of:
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setting a mask matrix;
determining a convolved image matrix via a convolution operation between the matrix of the road image and the mask matrix so as to identify luminosity discontinuities present in the image;
determining a binary image matrix in which each element has a first (0) or a second (1) binary value depending on the result of a comparison of a corresponding element of the convolved image matrix with a threshold value;
determining from the binary image matrix a representation of the marking stripes; and
whereinsaid step of setting the mask matrix includes determining a value L indicative of the number of elements of the image matrix corresponding to the width of the marking stripes wherein each row of the mask matrix comprises;
L contiguous elements having a first value;
at least one element having a value of zero being contiguous to and located on both sides of said L contiguous elements; and
a plurality of elements being contiguous to said at least one element having a value of zero and being located at the left and right ends of each row, said plurality of elements being a second value of opposite sign to said first value. - 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, 25, 26, 27, 28, 29, 30, 31)
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32. A method, in a system for aiding the guidance of a vehicle, for identifying marking stripes demarcating at least one road lane in a road image represented by a matrix of elements each indicative of the luminosity level of an elementary portion of the image, the method comprising the steps of:
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determining a first and a second convolved image matrix via a convolution operation between the matrix of the road image and, respectively, a first and a second mask matrix so as to identify luminosity discontinuities present in the image, the elements of each row of the second mask matrix being equal in reverse order to the elements of a corresponding row of the first mask matrix;
determining a first and a second binary image matrix in which each element has a first (0) or a second (1) binary value depending on the result of a comparison of a corresponding element, respectively, of the first and of the second convolved image matrix with, respectively, a first and a second threshold value;
determining a single binary image matrix via a logic AND operation between the corresponding elements of the first and of the second binary image matrix; and
determining from the single binary image matrix a representation of the marking stripes. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
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54. An apparatus, in a system for aiding the guidance of a vehicle, for identifying marking stripes demarcating at least one road lane in a road image represented by a matrix of elements each indicative of the luminosity level of an elementary portion of the image, the apparatus comprising:
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a circuit for setting a mask matrix;
a circuit for determining a convolved image matrix via a convolution operation between the matrix of the road image and the mask matrix so as to identify luminosity discontinuities present in the image;
a circuit for determining a binary image matrix in which each element has a first (0) or a second (1) binary value depending on the result of a circuit comparing a corresponding element of the convolved image matrix with a threshold value;
a circuit for determining from the binary image matrix a representation of the marking stripes; and
a circuit for determining a value L indicative of the number of elements of the image matrix corresponding to the width of the marking stripes, said circuit for setting said mask matrix further;
setting L elements of the mask matrix to a first value;
setting at least one element having a value of zero being contiguous to and located on both sides of said L elements; and
setting a plurality of elements being contiguous to said at least one element having a value of zero and being located at the left and right ends of each row, said plurality of elements being a second value of opposite sign to said first value. - View Dependent Claims (55, 56, 57)
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58. An apparatus, in a system for aiding the guidance of a vehicle, for identifying marking stripes demarcating at least one road lane in a road image represented by a matrix of elements each indicative of the luminosity level of an elementary portion of the image, the apparatus comprising:
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a circuit for determining a first and a second convolved image matrix via a convolution operation between the matrix of the road image and, respectively, a first and a second mask matrix so as to identify luminosity discontinuities present in the image, the elements of each row of the second mask matrix being equal in reverse order to the elements of a corresponding row of the first mask matrix;
a circuit for determining a first and a second binary image matrix in which each element has a first (0) or a second (1) binary value depending on the result of a comparison of a corresponding element, respectively, of the first and of the second convolved image matrix with, respectively, a first and a second threshold value;
a circuit for determining a single binary image matrix via a logic AND operation between the corresponding elements of the first and of the second binary image matrix; and
a circuit for determining from the single binary image matrix a representation of the marking stripes.
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Specification