Sheet-surface analyser and method of analysing a sheet-surface
AssigneePaper Australia Pty Ltd.
InventorsMichael Reich, Rafik Faltas
Life of this patent
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Abstract
The present invention relates to a sheet-surface analyser (10) including illuminating means (32) for casting shadows on the sheet-surface; capturing means (36) for capturing an image of the shadows; analysing means (40) for analysing the captured image to thereby analyse the sheet surface; and curving means (22) for curving the sheet, wherein the illuminating means and the curving means are configured to enable the illuminating means to cast shadows on a curved part of said sheet-surface, and the capturing means is configured to capture said shadow-image.
Claims19
A sheet-surface analyser comprising:
- illuminating means for casting shadows on a sheet-surface;
- capturing means for capturing an image of the shadows;
- analysing means for analysing a captured shadow-image to thereby analyse the sheet-surface;
- and
- curving means for curving the sheet,
- wherein the illuminating means and the curving means are configured to enable the illuminating means to illuminate a curved part of the sheet-surface so that features of the sheet-surface cast shadows on the sheet-surface and the capturing means is configured to capture said shadow-image, the analysing means comprising a processor and a computer readable medium storing a computer program which when executed by the processor derives a matrix of rows and columns of light-intensity values from the captured shadow-image and calculates a sheet-surface value from the matrix wherein in calculating the sheet-surface value′ deviation values of respective rows and columns are calculated, the deviation value being a measure of average deviation of the light intensity values in said row or column from a mean value in said row or column, and wherein a selected region of the matrix comprising one row and/or column having a maximum deviation value is weighted to contribute more to the sheet-surface value than a remainder of the matrix.
A method of analysing a sheet surface comprising the steps of:
- curving the sheet;
- casting a shadow on a surface of the curved sheet by illuminating the sheet;
- capturing an image of the shadow;
- and
- analysing a captured shadow-image by deriving a matrix of rows and columns of light-intensity values from the captured shadow-image, and calculating a sheet-surface value from the matrix, wherein in calculating the sheet-surface value, deviation values of respective rows and columns are calculated, the deviation values being a measure of average deviation of the light intensity values in said row or column from a mean value in said row or colunm, and wherein a selected region of the matrix comprising one row and/or column having a maximum devation value is weighted to contribute more to the sheet-surface value than a remainder of the matrix.
Dependencies are inferred from the claim text.