Computer-aided detection of lung nodules
First Claim
1. A method of forming an image of body structures from an image data set, notably for highlighting potential nodular structures in a lung, which method includes the steps ofa) forming a binary data set in which the pixels present in the image data set are subdivided into pixels which are to be marked and those which are not to be marked, in which stepa1. a first filtering operation is performed in which a distance value is determined for each pixel, which distance value corresponds to the shortest distance between the pixel and the edge of the image structure in which the pixel is situated, and in which those pixels are selected from the binary data set whose distance value is below a predetermined distance limit value,a2. a second filtering operation is performed in which those previously selected pixels remain selected which are directly neighbored in both directions of at least one straight line, extending through the pixel, by two pixels having a smaller distance value,a3. a third filtering operation is performed in which those previously selected pixels remain selected for which the surrounding pixels, situated at a distance corresponding exactly to the distance value of the pixel, have a distance value which is a predetermined distance difference value smaller than the distance value of the pixel to be tested itself,b) forming a marked image data set from the image data set by marking the pixels having been selected after the last filtering operation in the binary data set, andc) forming the image of the body structure from the marked image data set.
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Abstract
The invention relates to a method and a device for forming an image of body structures from an image data set, notably for highlighting potential nodular structures (KI; KA) in a lung. The problem to be solved by the invention is to achieve automatic highlighting of potential nodular structures in methods of this kind. This is realized in that in a plurality of steps a binary data set is formed in which all pixels present in the image data set are subdivided into pixels to be marked and those not to be marked, a first filtering operation being performed in which for each pixel (D) there is determined a distance value which corresponds to the shortest distance between the pixel and the edge (KAG) of the image structure (KA) in which the pixel is situated, those pixels being selected from the binary data set whose distance value is below a predetermined distance limit value, there being performed a second filtering operation in which those previously selected pixels remain selected which are directly neighbored by two pixels having a smaller distance value in both directions of at least one straight line which extends through the pixel, there being performed a third filtering operation in which those previously selected pixels remain selected for which the surrounding pixels, being situated at a distance corresponding to the distance value of the pixel, have a distance value which is a predetermined distance difference value smaller than the distance value of the pixel to be tested itself, the pixels thus selected being used to form an image in which the selected pixels are highlighted.
17 Citations
14 Claims
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1. A method of forming an image of body structures from an image data set, notably for highlighting potential nodular structures in a lung, which method includes the steps of
a) forming a binary data set in which the pixels present in the image data set are subdivided into pixels which are to be marked and those which are not to be marked, in which step a1. a first filtering operation is performed in which a distance value is determined for each pixel, which distance value corresponds to the shortest distance between the pixel and the edge of the image structure in which the pixel is situated, and in which those pixels are selected from the binary data set whose distance value is below a predetermined distance limit value, a2. a second filtering operation is performed in which those previously selected pixels remain selected which are directly neighbored in both directions of at least one straight line, extending through the pixel, by two pixels having a smaller distance value, a3. a third filtering operation is performed in which those previously selected pixels remain selected for which the surrounding pixels, situated at a distance corresponding exactly to the distance value of the pixel, have a distance value which is a predetermined distance difference value smaller than the distance value of the pixel to be tested itself, b) forming a marked image data set from the image data set by marking the pixels having been selected after the last filtering operation in the binary data set, and c) forming the image of the body structure from the marked image data set.
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13. A device for forming an image of body structures from an image data set, notably for highlighting potential nodular structures in a lung, which device comprises
a) means for forming a binary data set by subdividing the pixels present in the image data set into pixels which are to be marked and those which are not to be marked, including a1. means for performing a first filtering operation in which a distance value of the previously filtered pixels is determined, which distance value corresponds to the shortest distance between the pixel to be tested and the edge of the image structure in which the pixel to be tested is situated, those previously filtered pixels of the binary data set being selected whose distance values are below a predetermined distance limit value, a2. means for performing a second filtering operation in which those previously filtered pixels are selected which are surrounded only by pixels having a smaller distance value at a distance which corresponds to or is smaller than the distance value of the pixel at least along one straight line which extends through the pixel, a3. means for performing a third filtering operation during which those previously filtered pixels are selected for which the surrounding pixels, being situated at a distance corresponding to the distance value of the pixel, have a distance value which is a predetermined distance difference value smaller than the distance value of the pixel to be tested itself, b) means for forming a marked image data set from the image data set by marking the pixels having been selected after the last filtering operation in the binary data set, and c) means for forming the image of the body structure from the marked image data set.
Specification