Method and apparatus for digitally displaying an enhanced X-ray image

Claim 1

A method for displaying an X-ray image wherein an X-ray is irradiated toward a subject, an image of the X-ray having passed through the subject is converted into an image signal, the image signal is digitized and stored in an image memory means, and thereafter X-ray image data consisting of digital values are subjected to gradient conversion and then displayed on a screen or a recording medium, said method comprising; converting the X-ray image data with the gradient characteristics of γ>1 in the case where the values of the input data are in an interested region of a predetermined range, converting the X-ray image data with the gradient characteristic of γ=1 in the case where the values of the input data are uninterested region outside the predetermined range, and converting the input data inside the boundary of the interested region into output data consistently greater than 0 and wherein a ratio of an increment of output data of gradient characteristics to an increment data input data thereof is indicated by γ.

Claim 2

A method for displaying an X-ray image wherein an X-ray is irradiated toward a subject, an image of the X-ray having passed through the subject is converted into an image signal, the image signal is digitized and stored in an image memory means, and thereafter X-ray image data consisting of digital values are subjected to gradient conversion and then displayed on a screen or a recording medium, said method comprising; converting the X-ray image data with the gradient characteristics of γ>1 in the case where the values of the input data are in an interested region of a predetermined range, converting the X-ray image data with the gradient characteristic of γ=1 in the case where the values of the input data are uninterested region outside the predetermined range, and converting the input data inside the boundary of the interested region into output data consistently greater than 0 and wherein a ratio of an increment of output data of gradient characteristics to an increment data input data thereof is indicated by γ.

Claim 6

An apparatus for displaying an X-ray image comprising: means for irradiating an X-ray toward a subject; means for regulating X-ray irradiating conditions; means for taking an image of the X-ray having passed through the subject and for converting the image into an image signal; analog-digital conversion means for converting the image signal into digital values; means for storing X-ray image data consisting of the digital values; means for conducting a gradient conversion on the X-ray image data on the basis of predetermined gradient characteristics; and means for displaying the X-ray image data on which gradient conversion has been conducted, on a screen or a recording medium; and wherein; when a ratio of an increment of output data of a table of gradient characteristics to an increment of input data thereof is indicated by γ, means for conducting a gradient conversion conducts conversion with the gradient characteristics of γ>1 in the case where the values of the input data values are in an interested region of a predetermined range, and conducts conversion with the gradient characteristics γ=1 in the case where the values of the input data values are in an uninterested region outside the predetermined range, while said means converts input data inside the boundary of the interested region into an output data consistently greater than 0.

Claim 7

An apparatus for displaying an X-ray image comprising: means for irradiating an X-ray toward a subject; means for regulating X-ray irradiating conditions; means for taking an image of the X-ray having passed through the subject and for converting the image into an image signal; analog-digital conversion means for converting the image signal into digital values; means for storing X-ray image data consisting of the digital values; means for conducting a gradient conversion on the X-ray image data on the basis of predetermined gradient characteristics; and means for displaying the X-ray image data on which gradient conversion has been conducted, on a screen or a recording medium; and wherein; when a ratio of an increment of output data of a table of gradient characteristics to an increment of input data thereof is indicated by γ, means for conducting a gradient conversion conducts conversion with the gradient characteristics of γ>1 in the case where the values of the input data values are in an interested region of a predetermined range, and conducts conversion with the gradient characteristics γ=1 in the case where the values of the input data values are in an uninterested region outside the predetermined range, while said means converts input data inside the boundary of the interested region into an output data consistently greater than 0.