WO2010026606A1

WO2010026606A1 - Method and apparatus for digitally achieving images on photographic films

Info

Publication number: WO2010026606A1
Application number: PCT/IT2008/000573
Authority: WO
Inventors: Raffaele De Fazio; Giuseppe Ravasio
Original assignee: Giorgini, Aurelio
Priority date: 2008-09-08
Filing date: 2008-09-08
Publication date: 2010-03-11
Also published as: CN102217297A; EP2351347A1; BRPI0822767A2

Abstract

Method for digitally capturing images placed on a photographic film, by an apparatus (1) comprising an outer casing (2) provided with at least one supporting plane (3), substantially transparent, for the photographic film, and wherein at least one light source (5) provided with means (6) for directing the light beams, as well as at least one static device (7) for digitally capturing images, are accommodated, and wherein the afore said static device (7) for capturing images receives at least the light beams emitted by the light source (5) and reflected by the photographic film. The method comprises the steps of: disposing on the supporting plane (3) at least one photographic film on which one or more images are reproduced; illuminating the photographic film by a light beam (5) in such a way that the light beams are directed towards the supporting plane (3) along a direction tilted at an angle ranging from 33° to 38° relative to the normal to such a supporting plane (3); capturing the image being present on the photographic film by the static device (7) for digitally capturing images.

Description

"METHOD AND APPARATUS FOR DIGITALLY ACHIEVING IMAGES ON

PHOTOGRAPHIC FILMS"

_******

FIELD OF THE INVENTION The present invention refers to a method and an apparatus for digitally capturing (achieving) images placed on photographic films, as for example negatives or slides, and particularly for medical use, as well as radiographs, mammographs or similar. The digitalization of photographic films with impressed images for medical use, in addition to be an essential activity to allow storing in digital files of those photographic films produced in the past, is a technique that is becoming more and more popular, in combination with the analogical capturing of radiographs or mammographs. Indeed it has been found that, in the known art, the analogically technique for realizing radiographs or mammographs is more exact, and thereby allows better diagnosis relative to that is obtained with a completely digitally technique. As a result, the analogically capturing of medical images, that is on photographic film and their subsequent digitalization for digitally storing such radiographs or mammographs, are still largely used. BACKGROUND ART

Apparatuses are known for digitally capturing images on photographic films, and particularly of radiographs or mammographs, comprising a fixed support for the photographic film bearing the radiograph or mammograph, a mobile device for capturing such a radiograph or mammograph, for example comprising a CCD (Charged - Coupled Device), or a photocell, and a corresponding focusing optics, as well as an illuminating source specifically shaped to illuminate the photographic film diffusely and homogeneously. The European Patent Application EP-A-0566999, in the name of EASTMAN KODAK, describes an optic scanner for capturing radiographs wherein the illuminating source comprises a laser beam being deflected, under control, by an apposite reflector onto the radiograph. The controlled deflection of the laser beam and the corresponding movement of the radiograph relatively to the latter, allows the laser beam to fly and run through every point of the radiograph itself with a certain geometry. The laser beam running through the radiograph is then detected by an optic collimator and by a corresponding sensor (for example a photocell), that are placed on the opposite side of the laser beam relative to the radiograph. In addition the laser beam is sent onto the radiograph surface with an angle different from 90°. Such a solution, although is able to minimize possible scanning errors due to the overlapping of the light waves reflected by the radiograph with the incident light waves, is still particularly complex, and further presupposes that the radiograph is fitted into the scanning apparatus in an apposite seating, for later being moved/dragged relative to the laser beam, with a consequent extension of the scanning times of each radiograph. The French Patent Application FR 2672760, in the name of Consigny, describes a scanner for radiographs, or mammographs, of the type provided with a device for indirectly illuminating the supporting plane over which the radiograph or mammograph is placed. More particularly, the illuminating device is placed in a casing for top closing the scanner, and comprises one or more light sources, a diffuser placed over them, and a concave mirror diffusing the light beams over the supporting plane with the radiograph, or mammograph. The light beams running through the radiograph, or mammograph, in this way are then detected by an apposite photosensitive sensor (for example a CCD), placed under the supporting plane for the radiograph or mammograph themselves. In this case too, although the laser beam use is not expected, the medical image illumination on the photographic film happens on the opposite side, relating to the image itself, relative to the digital image capturing device, with the consequent arrangement complexity and the need of high light energy. The Patent Application FR 2672760 further provides that the employed scanner is of traditional type, or rather of the type wherein the image capturing device, that is the photosensitive sensor, is moveable relative to the radiograph or mammograph to be digitalized.

It is further known to realize apparatuses for digitally capturing images placed on a paper medium comprising a base plane for the paper medium, a static device for digitally capturing images, that is placed downwards an optical path linking the base plane with such a device, as well as means for illuminating the medium, on which the image to be captured is reproduced, that are placed between the base plane and the digitally capturing device. Particularly, in such apparatuses, there is not any relative movement between the digitally capturing device and the base plane the medium with the image to be captured is placed on, because the whole image is at the same time detected and captured thanks to the afore said optical path and the digitally capturing device used.

For example, the United States Patent US 4701809, in the name of BARRET, teaches to realize such an apparatus, wherein the optical path, covered by the reflected light of the image to be captured, comprises a trapezoidal shaped mirror, returning the image towards the digitally capturing device. The illuminating means for the medium further comprise tubular lamps provided with reflecting screens diffusely directing the light towards the base plane for the medium with the image. In the same way, the European Patent Application EP-A- 1021031, in the name of DIMEXWORLD SA, describes an apparatus for digitally capturing images wherein there is not any relative movement between the device for capturing images and the base plane for the medium with the image to be captured. Such an apparatus provides that the optical path, having an appropriate length, comprises a plurality of mirrors reflecting the image towards the capturing device, and that the illuminating means comprise an element able to direct the light beams towards the afore said base plane, at a defined angle. •_*

Both the BARRET patent and the European Patent EP-A-1021031 does not describe, nor suggest, the possibility of capturing images placed on photographic films, such as particularly radiographs or mammographs. Therefore, on one hand the known art teaches to capture images placed on photographic films, that is on at least partially transparent media, by complex apparatuses presenting a certain slowness in capturing images, wherein the digitally capturing device for images detects the light fluxes passing through the film itself, and on the other hand there are more simple apparatuses, and having a quicker activation, wherein the device for capturing images detects the light fluxes reflected from the image, the apparatuses being considered evidently inappropriate for capturing images placed on photographic films. It therefore an object of the present invention to realize a method for digitally capturing the images placed on photographic films that would be of simple realization and assume the use of a not structurally complex apparatus for its implementation.

Another object of the present invention is to realize a method, and a corresponding apparatus, for digitally capturing images on photographic films, such as particularly radiographs and mammographs, allowing a quick and accurate capture of such images. SUMMARY OF THE INVENTION

These and other objects are obtained by the method for digitally capturing images placed on a photographic film according to the first independent claim, and the subsequent claims dependent therefrom, as well as the corresponding apparatus for digitally capturing images placed on the photographic film, according to the sixth independent claim and the subsequent dependent claims. The method for digitally capturing images placed on a photographic film, or plate, according to the present invention, is implemented by an apparatus comprising an outer casing provided with at least one supporting plane, substantially transparent, for the photographic film, and wherein at least one light source provided with means for directing the light beams, as well as at least one static device for digitally capturing images, are accommodated. Such a static device for capturing images further receives at least the light beams emitted by the light source and reflected by the photographic film. The method of the present invention comprises the steps of: disposing on the supporting plane at least one photographic film on which one or more images are reproduced; illuminating the photographic film by the afore said light source; - capturing the image being present on the photographic film by the afore said static device for digitally capturing images.

The method further provides that, in the step of illuminating the photographic film, the light beams are directed towards the supporting plane, along a direction that is tilted at an angle ranging from 33° to 38°, and preferably at an angle ranging from 33° to 34°, relative to the normal (the perpendicular) to such a supporting plane.

As the Applicant could surprisingly notice, the choice to direct the light beams of an illuminating source, functionally placed between the base plane for the photographic film and the digitally capturing device, such that the latter would capture the beams reflected from the film itself, along a direction at an inclination angle, relative to the normal to the supporting plane, comprised in the range afore reported, allows to obtain quick and accurate captures of the images being present on such photographic films, and particularly on radiographs or mammographs, without, the need of generating and detecting a consistent light flux running through these latter.

Particularly, the inclination angle of the light beams relative to the supporting plane for the photographic film reveals sufficient to moreover render unnecessary the presence of a reflecting screen situated over the photographic film itself, and then of the corresponding supporting plane. Such a solution, revealing optimal because it prevents the light beams from hitting the operator eyes too, this allowing the free use of sources emitting light beams in the wave lengths of ultraviolet or infrared rays, may be easily implemented on a structurally easy layout apparatus, that allows instant and accurate captures of the images placed on the photographic films. Therefore, according to another aspect of the present invention, it is provided an apparatus for digitally capturing images placed on a photographic film, for example on a radiograph or mammograph, comprising an outer casing provided with at least one supporting plane, substantially transparent, for the photographic film, and wherein at least one light source, provided with means for directing the light beams, as well as at least one static device for digitally capturing images, are accommodated, and wherein the afore said static device for capturing images receives at least the light beams emitted by the light source and reflected by the photographic film of which capturing the corresponding images is intended. Such an apparatus, advantageously, provides that the afore said means for directing the light beams lead the light beams towards a supporting plane, along a direction tilted at an angle ranging from 33° to 38°, and preferably at an angle ranging from 33° to 34°, relative to the normal to the supporting plane.

According to a particular aspect of the present invention, the light source of the apparatus for digitally capturing the images present on the photographic film comprises one or more tubular electroluminescent lamps, preferably powered by a switching power supply operative with a frequency comprised between 20 and 70 KHz, or a plurality of LED (Light Emitting Diodes). According to another aspect of the present invention, the light source provides a top diffuser, that is interposed between the lamp, or lamps, of the light source and the apparatus supporting plane, comprising a surface, substantially transparent, conveniently shaped to diffuse the light with a substantially hemispheric symmetry, as well as a bottom reflecting screen, that is situated on the opposite side from the diffuser relative to the lamp, or lamps, of the illuminating source itself. According to a further aspect of the present invention, the afore said means for directing the light beams comprise an array of reflecting thin plates, disposed in such a way to form a plurality of cells with a tilted axis relative to the normal to the supporting plane. BRIEF DESCRIPTION OF THE DRAWINGS A preferred embodiment of an apparatus according to the present invention will be now described, for purposes of illustration only and not limitative, for implementing a particular embodiment of the method herein claimed for digitally capturing images present on the photographic films, referring to the accompanying drawings, wherein: figure 1 is a schematic side section view of an apparatus according to a particular aspect of the present invention; figure 2 is a schematic section view of a directing element for the light beams operable in the apparatus of figure 1 ; figure 3 is an axonometric view of two details of the directing element of figure 2; - figure 4 is a schematic partial top view of the element of figure 2; figure 5 is a schematic view, partially cut - away, of a light source operable in the apparatus of figure 1.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE PRESENT INVENTION First referring to figure 1 , the apparatus 1 for digitally capturing images placed on a photographic film, preferably a radiograph or a mammograph, according to a preferred embodiment of the present invention, comprises an outer case 2, shaped as a parallelepiped, provided, on its top horizontal surface, with a supporting plane 3, substantially transparent and preferably glassy, the radiograph or mammograph that are intended to be captured resting thereon.

Within the casing 2 a plurality of reflecting elements 4a, 4b, 4c, 4d are housed, preferably constituted by flat mirrors, which define an optical path a+b+c+d+e of an appropriate length, and anyway greater than, or equal to, 1 meter, connecting the supporting plane 3 to a device 7 for digitally capturing the images present on the radiograph or mammograph rested on the same plane 3.

The device 7 for digitally capturing images may be constituted by a common video camera with a CCD sensor and optics having focal length of 35 mm, and may be operatively connected by memorizing and storing means, not illustrated, of the images captured by the device itself 7. Such a device 7 for digitally capturing images (video camera) is further static, that is to say it is fixedly mounted in the casing 3, so that the apparatus 1 results to be without moving parts during the capture of the images present on the radiographs or mammographs, or other photographic film type. The illuminating of the radiograph or mammograph, whose images are intended to be captured, is assigned to a light source 5, provided with means 6 for directing the light beams towards the supporting plane 3. The light beam 5 and the means 6 for directing the light beams are both comprised within the casing 2 and are set up in such a way that the light beams emitted by the source 5 will reach the supporting plane 3, and then the radiograph or mammograph, with an angle α not null relative to the normal (perpendicular) to the supporting plane 3.

The shape and the arrangement of the light source 5, the means 6 for directing the light beams, the mirrors 4a, 4b, 4c, 4d and 4e, as well as of the video camera 7, are such that the latter mainly receives, or at least receives, the light beams reflected from the radiograph or the mammograph laid on the supporting plane 3. That is, the functional scheme of the apparatus 1 , according to the present invention, provides that the light beams responsible for illuminating of the images to be captured have not to necessarily pass through the photographic film (radiograph or mammograph) to reach the video camera 7, being sufficient that such light beams are reflected from such a photographic film before reaching the video camera 7, or other device for capturing images. That is allowed by the fact that, as the Applicant could noticed, an appropriate selection of the inclination angle α of the light beams directed towards the supporting plane 3, relative to the normal to the latter, allows the accurate capture, and substantially without defects, of the images present on radiographs, mammographs, or other type of photographic film, while maintaining the video camera 7 fixed and not necessarily providing further auxiliary illuminating sources.

As the Applicant could noticed, the angle α that permitted to obtain all afore described, that is a accurate and not distorted capture of the images present on the substantially transparent media, by using principally the light reflected from such media, is comprised between 33° and 38° and preferably is comprised between 33° and 34°. Referring now to figures from 2 to 4, these show more in detail the means 6 for directing the light beams emitted from the light source 5 allowing to send the light beams towards the supporting plane 3 with an angle α, relative to the normal to plane 3 itself, comprised between 33° and 38°. Such a means 6 for directing the light beams comprise a base structure 8 on which slanted axis cells 10 branch off, these latter being constituted by a plurality of walls 9, realized in a reflecting material, as for example aluminum. The cells 10, having tubular shape with a quadrangular section and axis directed according to the angle α selected in the projecting step, allow to direct the light beams coming from the light source 5, placed immediately under such directing means 6.

Such cells 10, according to a preferred aspect of the present invention, have a reciprocal parallel axis and then constitute, in a plant view, a regular array, as can be seen for example in figure 4. The walls 9 of the cells 10 may be realized by a plurality of thin plates 11, 12 in a reflecting material that, provided with appropriate parallel notches, are intersecting as shown in figure 3.

More particularly, a plurality of thin plates 11 , reciprocally parallel and provided with parallel notches, orthogonal to the engaging edge of each thin plate 11, are disposed in such a way as to engage, at a right angle, a corresponding plurality of thin plates 12 provided with parallel notches which are slanted relative to the engaging edge of each thin plate 12. The crossing of the thin plates 11 , having orthogonal notches, with the thin plates 12, having slanted notches, generates the afore said array (or grid) of cells 10 having a tilted axis, as well as the afore said base structure 8 of the means 6 for directing the light beams.

As mentioned before, the axis inclination of the cells 10, as well as the arrangement of the means 6 for directing the light beams into the outer casing 2 of the apparatus 1 , and of the supporting plane 3, allow to lead the light beams towards the supporting plane 3 for the radiographs or mammographs at the aforesaid angle α comprised between 33° and 38°, and preferably comprised between 33° and 34°.

It has to be observed that any other means for directing the light beams known in the art can be likewise utilized, provided that it guarantees the obtaining of the angle α afore described. The figure 5 shows, in a top schematic view, partially cut - away, the illuminating source 5, preferably utilized with the afore said means 6 for directing the light beams, into the casing 2 of the apparatus 1. Such an illuminating source 5 comprises, according to a particular aspect of the present invention, a plurality of LED 15a, 15b, 15c, 15d, 15e disposed on a reflecting screen 14, under a diffuser 13, of which in figure 5 only a portion can be viewed.

The reflecting screen 14 is particularly shaped to parallel reflect the light beams emitted from the LED 15a, 15b, 15c, 15d, 15e, or from another electric powered illuminating elements, towards the diffuser 13, that is in turn placed immediately under the means 6 for directing the light beams. In such a way, practically all the light beams emitted from the LED 15a, 15b, 15c, 15d, 15e are conveyed towards the diffuser 13, and then towards the directing means 6 and finally towards the supporting plane 3. The diffuser 13 is advantageously constituted, according to a particular aspect of the present invention, by a substantially transparent plate-shaped element, which presents its own lower surface, that is the surface at the illuminating elements 15a - 15e, smooth, and its own upper surface shaped, for example by an array of conveniently shaped reliefs, such that to outwardly spread, towards the directing means 6, the light beams having a substantially hemispheric symmetry. Such an assembly constituted by the reflector 14 and the diffuser 13 allows to maximize the light transmission through the directing means 6 and to render as much homogeneous as possible the light distribution registered at the supporting plane 3 and then of the radiograph or mammograph to be captured.

The wave lengths that the illuminating source 5 may emitted could be selected in the visible range or in the infrared (IR) or ultraviolet (UV) ray range.

Particularly, it has been found particularly efficient for capturing images present on radiographs or mammographs, the use of LED being able to emit light with a wave length in the ultraviolet ray range (UV: wave length comprised between 10 nm - 400 nm).

As mentioned yet, thanks to the particular shape and arrangement of the illuminating source 5 and of the means 6 for directing the light beams, the incident angle of the light beams onto the supporting plane 3 avoids the light beams from reaching the operator eyes, avoiding, in case of light source operating with wave lengths in the visible range, the operator glare and, in case of light sources operating with wave lengths in the UV or IR range, avoiding possible damages to the visual apparatus of the same operator. It has to be noticed that, although a plurality of LED 15a, 15b, 15c, 15d, 15e have been described as an illuminating element, any other electrically powered illuminating element, such as for example electroluminescent neon tubes, or halogen lamps, or bf still another type, might be equally utilized. For example, it is possible to use electroluminescent tubes, powered by a switching power supply operative with frequencies comprised between 20 KHz and 70 KHz, so as to avoid possible beats with the scanning frequencies of the video camera 7.

According to the present invention, the method for digitally capturing images placed on a photographic film, and particularly on radiographs or mammographs, may be implemented, according to a preferred aspect of the present invention, on the apparatus 1 afore described and comprises the steps of: a) disposing the radiograph, or mammograph, of which the images are intended to be captured, on the supporting plane 3 of the apparatus 1 ; b) illuminating, by said light source 5 and the corresponding means 6 for directing the light beams, the radiograph or the mammograph placed on the afore said supporting plane 3; c) capturing the light beams reflected by the radiograph, or mammograph, by a static device 7 for digitally capturing the images.

Such a method provides that the light beams are directed, thanks to the means 6, towards the supporting plane 3 along a tilted direction at an angle from 33° to 38°, and preferably from 33° to 34°, relative to the orthogonal direction to the supporting plane 3 itself.

As mentioned, preferably, the method provides that the wave length the light source 5 is operating therewith, can be comprised in the visible range, but also in the IR and UV range, with particular preference for the latter, because of the good experimental results obtained.

Claims

1. Method for digitally capturing images placed on a photographic film, by an apparatus (1) comprising an outer casing (2) provided with at least one supporting plane (3), substantially transparent, for the photographic film, and wherein at least one light source (5) provided with means (6) for directing the light beams, as well as at least one static device (7) for digitally capturing images, are accommodated, said static device for capturing images receiving at least the light beams emitted by said light source (5) and reflected by said photographic film, the method comprising the steps of: - disposing on said at least one supporting plane (3) at least one photographic film on which one or more images are reproduced; illuminating said photographic film by said at least one light source (5); capturing the image being present on said photographic film by said at least one static device (7) for digitally capturing images; the method being characterized in that in said step of illuminating said photographic film, the light beams are directed towards a supporting plane (3) along a direction tilted at an angle (α) ranging from 33° to 38° relative to the normal to said at least one supporting plane (3).

2. Method according to claim 1 , characterized in that said light beams are directed along a direction tilted at an angle (α) ranging from 33° to 34° relative to the normal to said at least one supporting plane (3).

3. Method according to any one of the preceding claims, characterized in that said step of illuminating the photographic film takes place by at least one source (5) emitting light radiations at least in the frequency range of the visible light.

4. Method according to any one of the preceding claims, characterized in that said step of illuminating the photographic film takes place by at least one source (5) emitting light radiations at least in the frequency range of the ultraviolet (UV) or infrared (IR) rays.

5. Method according to any one of the preceding claims, characterized in that said images placed on a photographic film are radiographs or mammographs.

6. Apparatus (1) for digitally capturing images placed on a photographic film, of the type comprising an outer casing (2) provided with at least one supporting plane (3), substantially transparent, for the photographic film, and wherein at least one light source (5) provided with means (6) for directing the light beams, as well as at least one static device (7) for digitally capturing images are accommodated, said static device (7) for capturing images receiving at least the light beams emitted by said light source (5) and reflected by said photographic film, characterized in that said means (6) for directing the light beams lead said light beams towards said at least one supporting plane (3) along a direction tilted at an angle (α) ranging from 33° to 38° relative to the normal to said at least one supporting plane (3).

7. Apparatus according the claim 6, characterized in that said means (6) for directing the light beams lead said light beams towards said at least one supporting plane (3) along a direction tilted at an angle (α) ranging from 33° to 34° relative to the normal to said at least one supporting plane (3).

8. Apparatus according to any one of the claims 6 or 7, wherein said at least one light beam (5) comprises one or more electroluminescent tubes, and/or one or more LED (Light Emitting Diodes) (15a, 15b, 15c, 15d, 15e) and/or one or more halogen lamps.

9. Apparatus according to claim 8, characterized in that said at least one light source (5) comprises one or more electroluminescent tubes supplied by a switching power supply operative with frequencies in the range between 20 and 70 KHz.

10. Apparatus according to any one of the claims from 6 to 9, characterized in that said at least one light source (5) is provided with a top d iff user (13), of the type comprising a substantially transparent surface shaped to diffuse the light with a substantially hemispheric symmetry.

11. Apparatus according to claim 10, wherein said means (6) for directing the light beams are placed immediately over said diffuser (13).

12. Apparatus according to any one of the claims from 6 to 11 , characterized in that said at least one light beam (5) is provided with a bottom reflecting screen (14).

13. Apparatus according to any one of the claims from 6 to 12 wherein said means (6) for directing the light beams comprise a plurality of reflecting thin plates (11 , 12), reciprocally crossing.

14. Apparatus according to claim 13, characterized in that said reflecting thin plates (11 , 12) make up an array of cells (10) with the axis tilted relative to the normal to the supporting plane (3).