Method for enhancing the contrast of an image

1. A method of enhancing a contrast of an image represented by a digital signal representation by decomposing said digital signal representation into a multi-scale representation comprising at least two detail images representing detail at multiple scales, modifying pixel values of said detail images to yield pixel values of a set of modified detail images by applying at least one conversion function to the detail images and computing a processed image representation by applying a reconstruction algorithm to the modified detail images wherein

a segmentation map is constructed wherein with each pixel of said image a label is associated indicating a tissue type which said pixel represents,

a tissue coefficient table is constructed relating a tissue coefficient with a scale of a layer and a tissue type of said pixel,

for each said pixel of the layer of multi-scale representation a tissue coefficient corresponding with the scale of said layer and with the tissue type of said pixel is retrieved, and

layers of said multi-scale representation are pixel-wise multiplied by a retrieved corresponding tissue coefficient.

2. A method according to claim 1 wherein for all said scales of the multi-scale representation an amount of contrast enhancement is amplified or attenuated by said tissue coefficient.

3. A method according to claim 1 wherein a parameterised conversion function q(x) is a monotonically increasing odd conversion function providing maximum amplification within an intermediate, most critical sub-range of pixel values of a detail image, and wherein the slope of said conversion function has a local maximum and a local minimum.

4. A method according to claim 2 wherein the layers of said multi-scale representation are pixel-wise multiplied with a coefficient that depends upon the scale.

5. A method according to claim 2 wherein the layers of said multi-scale representation are pixel-wise multiplied with a coefficient that depends upon the scale and wherein said coefficient is greater than one at the finest of said scales and gradually decreases to a value equal to one at medium scales and remains one at larger scales.

6. A method of enhancing a contrast of an image of a given examination type that is represented by a digital signal representation by converting said digital signal representation according to a conversion function, said conversion function being derived from a parameterised conversion function q(x) by giving specific values to parameters of said parameterised conversion function, wherein specific values for examination type dependent parameters are exclusively derived from said digital signal representation and wherein

a segmentation map is constructed wherein with each pixel of said image a label is associated indicating a tissue type which said pixel represents,

a tissue coefficient table is constructed relating a tissue coefficient with a scale of a layer and a tissue type of said pixel,

for each said pixel of the layer of multi-scale representation a tissue coefficient corresponding with the scale of said layer and with the tissue type of said pixel is retrieved, and

layers of said multi-scale representation are pixel-wise multiplied by a corresponding retrieved tissue coefficients.

7. A method according to claim 6 wherein for all scales of the multi-scale representation a maximum amplification is amplified or attenuated by said tissue coefficient.

8. A computer program stored on a computer readable carrier medium adapted to carry out the steps of claim 1 when run on a computer.

9. A computer program product stored on a computer readable carrier medium adapted to carry out the steps of the method of claim 6 .