GB2148659A

GB2148659A - Variable magnification scanning system

Info

Publication number: GB2148659A
Application number: GB08423006A
Authority: GB
Inventors: Rolf Lennart Stalfors
Original assignee: Victor Hasselblad AB
Current assignee: Victor Hasselblad AB
Priority date: 1983-09-20
Filing date: 1984-09-12
Publication date: 1985-05-30
Also published as: IT1176724B; IT8422723A0; GB8423006D0; GB2148659B; IL72977A0; SE446801B; JPS60106268A; IL72977A; SE8305047D0; IT8422723A1; SE8305047L; DE3433684A1

Abstract

In a device for the production of a digital signal from an image on a photographic film 4 which can be moved to enable digitation of a desired portion of the image, light source 2 illuminates the film and scanner 7 digitizes the image falling on it. An optical projection system 6, with variable magnification is positioned between the film and the scanner. When used as part of a facsimile machine, picture quality is improved since only the portion of interest of the image is digitized and transmitted. <IMAGE>

Description

SPECIFICATION Device for the production of electronic digital image formation The present invention relates to a device for the production of electronic, digital image information.

It is known that it is possible to make teletransmission of pictures, of the photographic type on wire by means of a telephoto transmitter (telefax). In such apparatuses the image formation is transferred in a first step to electric signals. This is made in an apparatus in which an optical scanning of a positive, photographic picture is made. The produced electric signals are transmitted by means of the telephone net work to a receiver which registers the signals and produces a related picture the image of which is substantially the same as the original image and on a paper.

An occupational group which has frequent need to transmit images are newspaper reporters who have photographs, in general black/white as an illustration to the reportages. However, a rapid telephoto transmission is often prevented by the relatively difficult preparation and especially when visiting a foreign place. It is namely possible to have equipment available so that the exposed film can be developed and thereafter be copied to a positive image in eniarged form adapted to the telephoto apparatus. Further, naturally a telephoto transmitter or similar must be available, which apparatuses in general are relatively expensive and also bulky to transport.

The picture received will be cut and will then be copied to a size adapted to the intended placement. This complicated chain means that the end result will represent a low image quality.

The device according to the invention has to its purpose to facilitate the transferring from an optical information of the motive the photographer will catch to an optimized, in electronic way registered information which is simple to transmit by means of wire or wireless. For this purpose the device according to the invention uses an analogue medium with relatively good resolution, type photographic film, and is characterized by a position for the analogue medium, a lighting means at said position for the lighting of the analogue medium, means provided to register a projected image and to digitize the same, which means can be of known type as a line scanner, and an optical projection system with variable magnification and positioned between the position for the analogue medium and the projection area of the digitalizing means.The position is provided as a resting by using a horizontal surface for the analogue medium and with an outside location on the device and provided to allow moving of the analogue medium in directions parallel to its, in relation to said horizontal resting surface substantially parallel picture plane so that the analogue medium can be slided relative to the axis of the projection system. Thereby different image portions can be projected on the digitalizing means partly through the movement and partly through changing of the magnification of the projection system.

In this way the desired information (and only the same) can be transmitted to a distant receiver so that an optimal image quality can be obtainable for the user of the picture. The image information picked directly from a developed negative, accordingly without any enlarging and copying of the negative to a predetermined suitable size, has to be made.

Especially it is preferable if in the device is comprised optical means for showing the image portion determined for scanning and electronic means for the registration of the scanned information and also means for the projection of the registered information in the form of a picture.

The invention will now be described and explained with reference to a figure shown on an accompanying drawing.

A main idea of the invention is a basic source for the image information to use an ordinary photographic film which is exposed in an ordinary photographic camera. It can be a negative film or a positive one, from the electronic point of view it has no importance; preferably it will however be transparent. In order to cut down the period between exposition and use of the developed film it is possible to use a film of the instant developing type, e.g. of the type Polaroid. A photographic film has a very good resolution compared to the resolution in a telephoto apparatus or in an electronic camera of the type using a solid state matris as image collector e.g. Mavicas 4.

As the image representation at the exposition more seldom will be exactly the desired one and just that the picture will bear more information than what is strictly necessary to transmit. According to a commonly used method the picture is enlarged and copied in an conventional way whereby it is necessary that the resulting picture has certain proportions to be adapted to the telephoto transmitter. The receiver will cut the picture to the right proportion and has to accept the picture in the resolution the transmission resulted in.

This fact means that usually a substantial part of the capacity of the transmitting channel has been used for the transmission of information which then will not be used. According to the invention the essential part of the image is chosen before the transmission and the maximal obtainable resolution of the image scanner will be used only for this image portion without any intermediate copying and in order to utilize the good resolution of the photographic picture in the highest degree possible. This will be made by means of a device according to the following.

From the figure on the drawing is evident that in the device for transmission of image information is included beside the housing 1 lighting means 2, a holder 3 for the film 4 which is possible to manipulate in the ray path from the lighting means, a first mirror 5, a lens 6 with variable magnification and scanning means 7.

In the scanning means 7 is included, attached on a movable slide 8, a linescanner 9 which for example can be of the CCD-type.

The slide 8 is by means of a motor in a known way movable transverse to the longitu dinal direction of the line scanner 9 so that a scanning line by line can be made of the image projected from the film 4 via the mirror 5 and the lens system 6 and on the scanning means 7.

The mirror 5, the lens system 6 and the scanning means 7 are carried by a frame beam 11. To the frame beam 11 is attached a second mirror 1 2 which is pivotable between two positions around a shaft 1 3. When the mirror 1 2 is in the position shown in the figure the projection from the lens system 6 is projected upwards on an opaque screen 14 from which it can be read how the picture looks, which the scanning means will register when the mirror 1 2 is pivoted downwards to the beam 11. By means of observation of the picture shown on the opaque screen 14 and a simultaneous manipulation of for one part the position of the picture holder 3 under the lighting means and for the other part the magnification degree of the lens system 6.A focusing can be made and the image portion which is the most relevant can be chosen.

When the image portion is chosen the mirror as mentioned above will be pivoted down towards the beam 11 so that it will be positioned at the side of a ray path representing the projected image. Thereafter the scanning means can register the picture after manoeuvering one of the keys on a manual 1 5. The manual 1 5 comprises controls for other necessary functions as on/off, transmitting, start/stop and so on. The scanning means is so provided that at the beginning of the registration the line scanner is in position for reading a border line. After the reading of the same the motor 10 will move the slide 8 and the line scanner 9 one line away and a new reading can be made and so on until the entire image is registered. The result of the registration is now stored in digital form in a memory 16, which can be of the type tape or disc.In order to make a control of the in electronic way stored picture before transmission the device is provided with a monitor 1 7.

When the registered image is approved by the operator the information is transmitted either in digital or analogue form via a channel to the receiver. Transmission in digital form can be to prefer in order to reduce the distur bances.

The invention is not limited to what is described and explained in the foregoing but several modifications are possible within the scope of the following claims. For example the light intensity in the lighting means 2 can be adjustable in order to complete an aperture in the lens system for variation of the grey scale at the registration. The registration means can be provided with another type of line scanner than the CCD-type. The picture holder 3 and the lighting means 2 can be made for projection of positive, opaque pictures (as in an episcope for example). The system allows also direct connection to a system for newspaper editing e.g. Libers TlPS-system. By means of an electronic organ incorrectnesses in the exposition and also in the image elements can be corrected. Transmission can also be made directly for each read line but hereby the checking possibility of the entire registered image before the transmission is eliminated. It is also possible to provide the device with a histogram display for adjusting of the projection.

Claims

1. Device for the production of an electronic, digital image information from an image registration on an analogue medium with relatively good resolution, type photographic film, wherein a position for the analogue medium, a lighting means at said position for the lighting of the analogue medium, means provided to register a projected image and to digitize the same, which means can be of known type as a line scanner, and an optical projection system with variable magnification and positioned between the position for the analogue medium and the projection area of the digitizing means whereby the position is provided as a resting by using a horizontal surface for the analogue medium and with an outside location on the device and provided to allow moving of the analogue medium in direction parallel to its, in relation to said horizontal resting surface substantially parallel picture plane so that the analogue medium can be slided relative to the axis of the projection system so that different image portions can be projected on the digitilizing means partly through the movement and partly through changing of the magnification of the projection system.

2. Device according to claim 1, wherein at least the main part of the projection system is attached to a frame beam which together with a housing is forming the frame of the device.

3. Device according to claim 2, wherein the frame beam is extending substantially horizontal, that the position for the analogue medium is positioned above the one end of the beam with the lighting means at least partly positioned above said position so that the ray path through the medium will be substantially vertical, whereby the frame beam at its end is provided with a mirror or similar for directing the ray path along the beam toward its other end to reach the digitizing means.

4. Device according to claim 3, wherein the frame beam being provided to carry the digitizing means on its said other end.

5. Device according to any of the claims 1-4, wherein optical means for showing the image portion choiced for scanning.

6. Device according to claim 5, wherein the optical means providing a mirror or similar positioned at the digitizing means for directing the ray path and one in the projection direction of the mirror positioned opaque screen with the mirror pivotable between two positions, in the one position brought out of the ray path so the same will reach the digitilizing means and in the other position pivoted into the ray path so it will be directed to the opaque screen.

7. Device according to claim 6, wherein the opaque screen is positioned on the housing and is directed substantially in the same direction as the position for the analogue medium.

8. Device according to any of the preceding claims, wherein electronic means, for the registration and storing of the scanned information and means for showing the registered information in image form are included.

9. Device according to any of the preceding claims, wherein it being provided to produce the scanned information in digital form and to store it digitally.

1 0. Device for the production of an electronic, digital image formation from an image registration on an analog medium, constructing substantially as herein described with reference to and as illustrated in the accompanying drawing.