Image contrast enhancement arrangement

Claim 1

A method of correcting for the loss of contrast caused by modulation transfer function (MTF) effects in angiographic imaging, said method enhancing the images of small objects without adversely affecting the images of larger objects, the correction being effective even when using only a single window for viewing both large and small objects, the said method comprising the steps of: acquiring x-ray image data for use in displaying blood vessels being imaged, providing homogeneous backgrounds for said blood vessels being imaged by subtracting image data acquired before the addition of contrast material into said blood vessels from image data acquired after the addition of contrast material into the blood vessels; determining the image contrast as acquired with total system MTF; inserting a value for the full width at half maximum (FWHM) of the MTF; and changing the scale of the determined image contrast based on said value of the FWHM of the MTF to cause the determind imaged contrast to approximate an ideal contrast not affected by the MTF contrast reduction to thereby correct for the loss of contrast due to MTF effects.

Claim 2

A method of correcting for the loss of contrast caused by modulation transfer function (MTF) effects in angiographic imaging, said method enhancing the images of small objects without adversely affecting the images of larger objects, the correction being effective even when using only a single window for viewing both large and small objects, the said method comprising the steps of: acquiring x-ray image data for use in displaying blood vessels being imaged, providing homogeneous backgrounds for said blood vessels being imaged by subtracting image data acquired before the addition of contrast material into said blood vessels from image data acquired after the addition of contrast material into the blood vessels; determining the image contrast as acquired with total system MTF; inserting a value for the full width at half maximum (FWHM) of the MTF; and changing the scale of the determined image contrast based on said value of the FWHM of the MTF to cause the determind imaged contrast to approximate an ideal contrast not affected by the MTF contrast reduction to thereby correct for the loss of contrast due to MTF effects.

Claim 10

A system for correcting for loss of contrast caused by modulation transfer function effects (MTF) in angiographic imaging, said system enhancing the images of small objects without adversely affecting the images of larger objects, the correction being effective even when only a single window for viewing the large and small objects is used, said system comprising: means for providing homogenous backgrounds for objects being imaged by subtracting images of blood vessels without contrast material added to the blood vessels from images of the blood vessels with contrast material added; means for determining the image contrast as acquired with total system MTF effects; means for inserting a value for the full width at half maximum (FWHM) of the MTF; and means for changing the scale of the determined imaged contrast based on said FWHM value of the MTF to cause the determined contrast to approximate an ideal contrast not affected by the MTF contrast reduction.

Claim 11

A system for correcting for loss of contrast caused by modulation transfer function effects (MTF) in angiographic imaging, said system enhancing the images of small objects without adversely affecting the images of larger objects, the correction being effective even when only a single window for viewing the large and small objects is used, said system comprising: means for providing homogenous backgrounds for objects being imaged by subtracting images of blood vessels without contrast material added to the blood vessels from images of the blood vessels with contrast material added; means for determining the image contrast as acquired with total system MTF effects; means for inserting a value for the full width at half maximum (FWHM) of the MTF; and means for changing the scale of the determined imaged contrast based on said FWHM value of the MTF to cause the determined contrast to approximate an ideal contrast not affected by the MTF contrast reduction.