WO2004081648A2

WO2004081648A2 - Lighting device mountable ona camera with flashl ight, and method therefor

Info

Publication number: WO2004081648A2
Application number: PCT/NL2004/000178
Authority: WO
Inventors: Gerardus Peterus Johannus Van Zetten
Original assignee: Dental Innovaties B.V.
Priority date: 2003-03-11
Filing date: 2004-03-11
Publication date: 2004-09-23
Also published as: NL1022891C2; WO2004081648A3

Abstract

Ring lighting unit (1) can be fastened to lens (3) in the manner shown in fig.2. In this position the light channel (10) (fig.3) connects to flashlight (5). When a photograph is taken the light from the flashlight will therefore be guided through a light channel (10). This channel (10) comprises walls (6, 7, 8, 9) and transitions therebetween. Light channel (10) transposes into in a reflection chamber which is bounded by annular reflector (13) and edge (12). In the mounted position the reflection chamber is further bounded by lens edge (21). A light diffuser (20) can be placed on the front side of the reflection chamber. Reflecting mirror (19) is arranged at the end of light channel (10) in a manner such that light from flashlight (5) is reflected to annular reflector (13). In order to enhance this, edges (12) and (21) can be provided with reflective material.

Description

LIGHTING DEVICE MOUNTABLE ON A CAMERA WITH FLASHLIGHT,

AND METHOD THEREFOR

The present invention relates to the field of lighting equipment for lighting objects when the objects are photographed. Known for this purpose, among others, are lamps, flashlights and reflection means for indirect light. In order to record an object from a relatively short distance, for instance closer than one metre, such known devices require either relatively complicated setups, or the object is unevenly lit, whereby the quality of the recorded photographic image leaves something to be desired.

In order to obtain a lighting device with an improved lighting quality which is relatively simple to apply, the present invention provides a lighting device for mounting on a camera with flashlight, comprising: - mounting means for mounting the lighting device on the camera,

- reflecting means for reflecting light away from the lens side of the camera,

- light guiding means for guiding light from the flashlight to the reflecting means.

Such a preferred embodiment has the advantage that it is easy to use when mounted on a camera. In practice the lighting is aligned with the lens in any position of the camera. The reflecting means preferably reflect the light forward from at least two sides of the lens. An object for photographing is hereby lit from two sides, as seen from the lens .

In a further preferred embodiment the reflecting means extend around the lens in annular manner, as seen from the front. It hereby becomes possible to light an object for photographing from all sides simultaneously, as seen from the lens, using light originating from the flashlight of the camera. This is particularly advantageous in the case of relatively small objects or objects situated relatively close to the lens when the photo is taken. A distance of 0-60 cm can be envisaged here. A specific example of an object for photographing using this device are the contents of the mouth, wherein the position of teeth and molars, the state of the teeth and molars and for instance gums, as well as dental elements arranged in the mouth, are important. A further example is application in dermatology, for instance for diagnosis or the transfer of accurate images. In this type of photography the quality of the lighting greatly enhances the quality of the recorded photographic image. In a further preferred embodiment of the lighting device, the mounting means are suitable for mounting on the lens of the camera. Many types of lens for cameras are provided in per se known manner with mounting means for protective hoods or for instance filters. Mounting means according to this embodiment which are adapted so as to engage on these mounting means of the lens enable very simple mounting of the lighting device on the camera .

In a further preferred embodiment, the lighting device comprises a channel from the flashlight of the camera to the reflecting means, in addition to a mirror for reflecting the light to the surface of the reflecting means. The form of the mirror is such that the light is distributed uniformly over the reflecting means in appropriate manner. The mirror can herein take the form of a part of a curved surface . An advantage of this embodiment is that as much light as possible is transferred from the flashlight to the final reflecting means . The mirror is preferably partially light- transmitting. If a part of the light is transmitted through the mirror, a good lighting of the object for photographing will likewise be possible at the position of the channel .

In order to obtain a uniform lighting of the object for photographing, the lighting device further comprises light diffusing means for diffusing the light reflected from the reflecting means. For this purpose one or more parts of frosted glass or white glass or an equivalent thereof from plastic can for instance be applied.

These diffusing means are preferably annular in order to extend around the lens as seen from the front of the lighting device. As specified in the foregoing, an object is hereby lit uniformly from all sides.

If the photographer determines through tests that a determined distance is very suitable for taking photos of a particular object, he/she can according to a further embodiment make use of positioning means for positioning the lighting device relative to an object for photographing. Such positioning means for instance comprise a chin spacer which can be placed against the chin of a person when the photographic recording is being made. It is also conceivable for such a positioning means to be placed against another part of the face or the body. If desired, the use of a plurality of supports gives a more stable positioning.

In a further preferred embodiment the positioning means comprise for this purpose at least one spacer as well as at least one opening which is arranged close to the reflector for arranging the spacer in the opening.

In a further preferred embodiment, the lighting device further comprises a lens. With a view to small distances between the lens and the object for photographing, the lens is preferably a macro-lens. A further aspect of the invention relates to an assembly comprising a lighting device as specified in the foregoing and a camera wherein the mounting means of the lighting device are suitable for mounting on the lens of the camera, and the light guiding means are arranged such that they guide the light from the flashlight of the camera.

A further aspect of the present invention relates to a method for assembling, by means of at least one computer, an ICC profile for a device as specified in the foregoing, comprising steps for measuring recording data for different colours.

Using ICC profiles a computer can take into account variations or specific characteristics of the hardware of equipment for recording, displaying or processing image data. ICC is the acronym of "international color consortium" . A profile comprises a description of the characteristics of the hardware, comprising for instance the colour range (gamut) of a printer, camera or screen. A computer with suitable software, or for instance hardware with a built-in processing unit, can process image data so that these are displayed in true-to-life manner using the hardware of the peripheral equipment. A further aspect of the invention relates to a method for using an ICC profile for a device as specified in the foregoing, for displaying, printing and/or processing image data by means of at least one computer .

The invention further relates to program code comprising an ICC profile for a device as specified in the foregoing.

A file which can be read by a computer preferably comprises an ICC profile for a device as specified in the foregoing . These aspects provide the advantage that recorded images can be displayed in true-to-life manner using a plurality of computer peripheral equipment . An efficiency and quality improvement is hereby also possible, such as by defining the colour spectrum specifically for dental, dermatological and other medical fields of application.

Further advantages, features and details of the present invention will be described hereinbelow on the basis of preferred embodiments. In the annexed figures:

- fig. 1 shows an exploded perspective view of an embodiment according to the present invention;

- fig. 2 shows a perspective view of the embodiment of fig. 1; - fig. 3 shows a side view of the embodiment of fig. fig . 4 shows a front view of the embodiment of fig .

- fig . 5 shows a schematic representation of a system according to an embodiment of the present invention;

- fig. 6 A, B, C show flow diagrams of embodiments of methods according to the present invention;

- fig. 7 is an exploded perspective view of a further preferred embodiment.

A ring lighting unit 1 (fig. 1, 2, 3, 4) can be fastened to a lens 3 of a camera 2. Camera 2 is a per se known digital camera with built-in flashlight 5. Alternatively, camera 2 could be a conventional film camera .

Ring lighting unit 1 can be fastened to lens 3 in the manner shown in fig. 2. In this position the light channel 10 (fig. 3) connects to flashlight 5. When a photograph is taken the light from the flashlight will therefore be guided through a light channel 10. Light channel 10 can be provided on the inside with reflective material for a high light transmission.

This channel 10 comprises walls 6, 7, 8, 9 and transitions therebetween. Light channel 10 transposes into in a reflection chamber which is bounded by annular reflector 13 and edge 12. The annular reflector is provided with a reflective layer. This layer is for instance specular. An alternative to specular is a layer of paint such as white or another tint with good reflection. In the mounted position the reflection chamber is further bounded by lens edge 21. A light diffuser 20 can be placed on the front side of the reflection chamber.

Reflecting mirror 19 is arranged at the end of light channel 10 in a manner such that light from flashlight 5 is reflected to annular reflector 13. In order to enhance this, edges 12 and 21 can be provided with reflective material.

Reflecting mirror 19 can be fixed to fastening point 17 by means of fixing eye 18. The form of mirror

19 is such that the light from the flashlight is reflected as much as possible in the direction of reflector 13. In one embodiment the mirror is replaced by a plate of whitened material, for instance with a white paint or a coating of sprayed plastic. Mirror 19 is preferably slightly translucent. The light- transmission is achieved in this embodiment by a small opening between the wall of the channel and plate 19. An alternative is a slightly light-transmitting coating for the mirror, or openings in the reflecting surface of the mirror. A part of the light can hereby be transmitted directly from the flashlight to diffusing ring 20, thereby achieving a uniform lighting of the object for photographing . A spacer 31 with positioning plate 32 are provided for positioning the ring lighting unit relative to the object for photographing. In order to make this spacer 31 naountable on the ring lighting unit at a suitable position, an edge 15 with openings 16 is provided around the ring lighting unit. The spacer can be placed in any of the openings 16.

Depending on the camera, a lens is available which is per se suitable for macro-recordings, or use is made of an extra detachable lens with a lens edge 21. Such a camera is shown in the embodiment of fig. 7. In this embodiment ring lighting unit 71 is provided with a substantially cylindrical wall 72 which extends from ring 73 arranged around the camera lens as far as the front side of ring lighting unit 71. This wall 72 preferably extends as far as or slightly beyond light diffuser 7 . This wall shields the lens from the flashlight. An advantage of this embodiment is that macro-recordings and normal recordings can be made without the detachable lens having to be removed. A doctor can hereby alternately make macro-recordings of a detail of a patient and for instance side view recordings of a patient, wherein only the camera setting need be changed. A ring lighting unit according to the present invention can be made to fit on any per se known camera with flashlight by varying dimensions.

In order to manage and process photographs made using the camera with ring lighting unit 1, a doctor makes use of software for managing and processing the photographs, such as image management and image communication software. The function of such software is that image information can be exchanged between cameras, screens, printers and/or different computers. As shown in fig. 5, a camera 61 with an ICC profile 68 can be connected to a computer or processing unit 62 in which image information is processed on the basis of the ICC profile. This information processing step can optionally be carried out in a camera equipped for this purpose. The resulting image information is transferred via a network to a processing unit or a computer 64 which displays the image in true-to-life manner using one or more ICC profiles of display devices such as a screen 67, a projector 66 or a printer 65. Use is made here of respective ICC profiles 70, 71 and 72. It is also possible for units 62 and 64 to function in a computer. The optional network enables the exchange of data between two locations of different practices or two rooms in one practice.

A camera with a ring lighting unit 1 has a determined hardware characteristic which can be recorded in an ICC profile. This operation (fig. 6A) starts in step 41 with calibration of the colour of an image from the camera. On the basis hereof a measurement is performed in step 42 and the ICC profile of the camera with ring lighting unit 1 is determined. This ICC profile is then added to a databank of an image management and/or communication software package and stored in step 44. If another camera is for instance applied and/or the environmental conditions in which the recordings are made have changed, steps 42,43,44 are repeated.

Before recordings are made using the camera with ring lighting unit 1 (fig. 6B) a step is performed of inputting and calibrating a digital image. A recording is then made in step 47 for further processing, such as for instance a recording of the inside of the mouth of a patient. This recording is added to the software for image management and image communication. In step 49 the image data are calibrated and/or optimized on the basis of a device-specific ICC profile and parameters relating to the camera with ring lighting unit 1 and/or ambient influences during making of the recording. A file with the resulting data is stored in step 50. In step 51 the data for display by means of a printer, screen or projector are transmitted for instance via a network.

The calibrated image of step 51 is received in step 52 for true-to-life display of the recording or photo (fig. 6C) . The specific device for display is determined and the associated ICC profile is selected and/or received from the specific device in step 53. In step 54 an operation is performed on the basis of the ICC profile, such that the device obtains image data which enable it to display the image in true-to-life manner with its own hardware characteristics. In an environment-specific ICC the ambient light can herein be taken into account, or the display on the screen can be calibrated while making allowance for the ambient light. It is likewise possible for a computer to perform both the display and the recording of images. It is also possible that the camera and/or a display device together have image processing means with which the method can be performed, and in such a configuration the camera can be connected directly to for instance the printer or screen. The calculations on the basis of the ICC profiles are then carried out in the printer or in the camera or partly in the camera and partly in the printer. If use is made of a spacer 31,32, an ICC profile can be created wherein the distance of the camera from the subject being photographed is specifically taken into account. The reliability of the true-to-life quality of the displayed image is hereby further increased. Possible variations can be inferred from the description by the skilled person. The rights sought are defined in the appended claims.

Claims

1. Lighting device for mounting on a camera with flashlight, comprising: - mounting means for mounting the lighting device on the camera,

- reflecting means for reflecting light away from the lens side of the camera,

2. Lighting device as claimed in claim 1, wherein the reflecting means reflect the light forward from at least two sides of the lens.

3. Lighting device as claimed in claim 1 or 2 , wherein the reflecting means extend around the lens in annular manner, as seen from the front.

4. Lighting device as claimed in one or more of the foregoing claims, wherein the mounting means are suitable for mounting on the lens of the camera.

5. Lighting device as claimed in one or more of the foregoing claims, wherein the light guiding means comprise a channel from the flashlight of the camera to the reflecting means and/or comprise a mirror for reflecting the light to the surface of the reflecting means.

6. Lighting device as claimed in claim 5, wherein the mirror is partially light-transmitting.

7. Lighting device as claimed in one or more of the foregoing claims, comprising light diffusing means for diffusing the light reflected from the reflecting means.

8. Lighting device as claimed in claim 7, wherein the diffusing means are annular.

9. Lighting device as claimed in claim 7 or 8, wherein the diffusing means comprise white glass, tinted plexiglass or light-transmitting plastic.

10. Lighting device as claimed in one or more of the foregoing claims, comprising positioning means for positioning the lighting device relative to an object for photographing.

11. Lighting device as claimed in claim 10, wherein the positioning means comprise at least one spacer as well as at least one opening which is arranged close to the reflector for arranging the spacer in the opening.

12. Lighting device as claimed in one or more of the foregoing claims, further comprising a lens.

13. Assembly comprising a lighting device as claimed in one or more of the foregoing claims and a camera wherein the mounting means of the lighting device are suitable for mounting on the lens of the camera, and the light guiding means are arranged such that they guide the light from the flashlight of the camera.

14. Method for assembling, by means of at least one computer, an ICC profile for a device as claimed in one or more of the foregoing claims, comprising steps for measuring recording data for different colours.

15. Method for using an ICC profile for a device as claimed in one or more of the claims 1-13 for displaying, printing and/or processing image data by means of at least one computer.

16. Program code comprising an ICC profile for a device as claimed in one or more of the claims 1-13.

17. File which can be read by a computer, comprising an ICC profile for a device as claimed in one or more of the claims 1-13.