# US 5,229,618 A · Radiation image read-out apparatus compensating for image distortion

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- Number: US 5,229,618 A
- Document ID: US5229618A
- Status: Granted
- Kind: A
- Application number: 07/778,659
- Filed: 1991-10-18
- Granted: 1993-07-20
- Earliest claimed: 1990-10-20
- Assignees: Fuji Photo Film Co., Ltd.
- Inventors: Nobuyoshi Nakajima
- Web page: https://patentgrep.com/patent/US5229618A

## CPC

- H04N 1/4072: {dependent on the contents of the original}
- G01N 21/5911: {of the scanning type (scanning per se G02B)}
- G01T 1/2014: {Reading out of stimulable sheets, e.g. latent image}
- G01N 2021/5949: {Correcting nonlinearity of signal, e.g. in measurement of photomedium}
- G01N 2021/5957: {using an image detector type detector, e.g. CCD}
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00)

## Abstract

A radiation image read-out apparatus comprises a read-out section for photoelectrically reading out a radiation image from silver halide film, on which the radiation image has been recorded, and thereby generating an image signal representing the radiation image. A signal conversion device converts the image signal such that distortion in the image signal, which distortion is caused to occur by nonlinear characteristics of the silver halide film, may be eliminated. A corrected image signal is thereby obtained, which can be processed commonly with an image signal obtained by reading out a radiation image from a stimulable phosphor sheet, on which the radiation image has been stored.

## Claims

### Claim 1

A radiation image read-out apparatus comprising:
i) a read-out section for photoelectrically reading out a radiation image from silver halide film, on which said radiation image has been recorded, and thereby generating an image signal representing said radiation image, and
ii) a signal conversion means for converting said image signal such that distortion in said image signal, which distortion is caused to occur by nonlinear characteristics of said silver halide film, is eliminated, and thereby generating a corrected image signal.

### Claim 2 (depends on 1)

An apparatus as defined in claim 1, wherein said read-out section is provided with a film digitizer, which is constituted of a light source for linearly irradiating light to said silver halide film having said radiation image recorded and developed thereon, and a line sensor located facing said light source with said silver halide film intervening therebetween, said line sensor detecting the light, which has been produced by said light source and has passed through said silver halide film.

### Claim 3 (depends on 1)

An apparatus as defined in claim 1, wherein said silver halide film is x-ray film.

### Claim 4 (depends on 1)

An apparatus as claimed in claim 1, wherein the converted image signal is compensated by said signal conversion means to make up for the fact that the amount of energy which has been recorded on said film is not linearly proportional to the image density of said radiation image.