Method of and apparatus for processing image outside irradiation field

Claim 1

A method of carrying out image processing on an image signal representing a radiation image which has been recorded using an irradiation field stop and has an irradiation field, comprising the steps of recognizing the irradiation field and converting the values of the image signal components corresponding to the picture elements recognized to be outside the irradiation field out of the image signal components which make up an image signal for reproducing the radiation image as a visible image according to a predetermined conversion formula, wherein the improvement comprises that the values of the picture elements in the area outside the irradiation field are converted according to the following formula, g(x,y)=h(t)·f(x,y)+{1-h(t)}·f.sub.max wherein f(x,y) and g(x,y) respectively represent the values of a picture element in a position (x,y) before and after the conversion, f max represents a maximum density and h(t) represents a continuous differentiable function.

Claim 2

A method of carrying out image processing on an image signal representing a radiation image which has been recorded using an irradiation field stop and has an irradiation field, comprising the steps of recognizing the irradiation field and converting the values of the image signal components corresponding to the picture elements recognized to be outside the irradiation field out of the image signal components which make up an image signal for reproducing the radiation image as a visible image according to a predetermined conversion formula, wherein the improvement comprises that the values of the picture elements in the area outside the irradiation field are converted according to the following formula, g(x,y)=h(t)·f(x,y)+{1-h(t)}·f.sub.max wherein f(x,y) and g(x,y) respectively represent the values of a picture element in a position (x,y) before and after the conversion, f max represents a maximum density and h(t) represents a continuous differentiable function.

Claim 3

An apparatus for carrying out image processing on an image signal representing a radiation image which has been recorded using an irradiation field stop and has an irradiation field, comprising a means for recognizing the irradiation field and a conversion means for converting the values of the image signal components corresponding to the picture elements recognized to be outside the irradiation field out of the image signal components which make up an image signal for reproducing the radiation image as a visible image according to the following formula, g(x,y)=h(t)·f(x,y)+{1-h(t)}·f.sub.max wherein f(x,y) and g(x,y) respectively represent the values of a picture element in a position (x,y) before and after the conversion, f max represents a maximum density and h(t) represents a continuous differentiable function.

Claim 4

An apparatus for carrying out image processing on an image signal representing a radiation image which has been recorded using an irradiation field stop and has an irradiation field, comprising a means for recognizing the irradiation field and a conversion means for converting the values of the image signal components corresponding to the picture elements recognized to be outside the irradiation field out of the image signal components which make up an image signal for reproducing the radiation image as a visible image according to the following formula, g(x,y)=h(t)·f(x,y)+{1-h(t)}·f.sub.max wherein f(x,y) and g(x,y) respectively represent the values of a picture element in a position (x,y) before and after the conversion, f max represents a maximum density and h(t) represents a continuous differentiable function.