WO2008033010A1

WO2008033010A1 - Device and method for positioning recording means for recording images relative to an object

Info

Publication number: WO2008033010A1
Application number: PCT/NL2007/000219
Authority: WO
Inventors: Albert Van Gool
Original assignee: Alb. Van Gool R & D; Stichting Saxion
Priority date: 2006-09-13
Filing date: 2007-09-10
Publication date: 2008-03-20
Also published as: NL1032488C2

Abstract

The invention relates to a device for positioning recording means for recording images, in particular a digital camera, relative to an object, in particular a body, and more in particular skin, wherein the device can emit light beams, which light beams intersect each other at a plurality of intersections. The invention also relates to a method for positioning recording means for recording images, in particular a digital camera, relative to an object, in particular a body, more in particular skin, by means of such a device. The invention can advantageously be applied in recording and analysing changes in the skin in the case of skin disorders.

Description

Device and method for positioning recording means for recording images relative to an object

Field of the invention

The invention relates to a device for positioning recording means for recording images, in particular a digital camera, relative to an object, in particular a body, and more in particular skin. The invention also relates to a method for positioning recording means for recording images, in particular a digital camera, relative to an object, in particular a body, more in particular skin, by means of such a device. The invention can advantageously be applied in recording and analysing changes in the skin in the case of skin disorders.

Background of the invention The exponential increase in the ageing population and the problems this involves represent a theme of which no-one can be unaware. Due to the increase in the number of elderly people the number of chronic illnesses will also rise, since it is a fact that ailments, disorders and diseases occur more frequently among those of advanced age. There are also concerns about the health care services in the future, since costs are expected to increase and the number of care staff will perhaps be insufficient. In (western) countries with health care costs under pressure there is therefore a need for forms of and systems for so-called 'teleconsulting and evaluation', i.e. options and aids for doctors, specialists and/or nurses to diagnose (home) patients remotely and subsequently prescribe therapy if necessary and be able to monitor the effect of the treatment. As in a physical visit by a patient to a medical expert, this often takes place on the basis of question and answer or visual observations; the expert talks to the patient or examines (part of) the patient. A telephone is an example of an aid for verbal teleconsulting. If the information required for the diagnosis is of a visual nature, visual teleconsulting could be formed via internet using photos.

An important application of teleconsulting and evaluation relates to visible skin disorders or traumas such as carcinoma, melanoma or chronic, for instance post-operative skin wounds. Existing methods of visual recording and analysis of skin disorders make use of scale divisions such as rulers, squared film or other comparing means which are laid adjacently of or over the disorder or injury during the recording, for later converting to scale on a PC the number of pixels found or millimetres measured on the screen. Although the validity and reproducibility of determined methods are acceptable to good, they are hardly applied in everyday clinical practice because they are very laborious and time-consuming.

A first diagnosis of a skin disorder does not as a rule take place remotely. Teleconsulting is particularly intended for periodic monitoring, in a manner which saves cost and effort, of the development of a skin disorder, for instance the reactions to therapies or medication. A system of teleconsulting for visible skin disorders must produce recorded images of these disorders, repeatedly if necessary, with sufficient quality and in mutually comparable manner, and calculate desired results therefrom. The system must thus be able to produce a recorded image of a diagnosed disorder more than once over a period of time in the most closely corresponding manner possible, and here compare these images to each other such that (comparative) diagnostic data result therefrom. The measuring method must thus be sufficiently sensitive (responsive) to actually also be able to detect and quantify changes in the clinical picture. For this purpose a first image will generally be the reference; subsequent images will be compared to the first or previous images for the purpose of analysing the development of the disorder; a substantially relative analysis is thus hereby carried out. The system must in principle be able to process all visually detectable skin disorders, wherein it is primarily the surface and - to somewhat lesser extent - the shape and, if desired, the colour which must be measured and compared. The photographic part of the system must be simple and suitable for use by a practitioner, carer, partner, volunteer carer or the patient him or herself. Such a system is not yet available, although there is a great need for it. The object of the invention is to meet this need.

Summary of the invention

The invention provides for this purpose a system for positioning recording means for recording images, in particular a digital camera, relative to an object, in particular a body, more in particular skin, which system comprises a device, which device can emit light beams, which light beams intersect each other at a plurality of intersections. The recording means are positioned relative to the object using the light beams. The positioning here preferably comprises of causing the intersections to at least substantially coincide with determined points in the object, for which points on the surface of the object are preferably chosen. The recording means can thus be positioned relative to the object. This relates to the mutual distance, and usually also the mutual angular position. Recordings can thus be made of the object in the course of time which can be readily compared to each other. The progression of or process of recovery from for instance a skin disorder can thus be properly monitored and analysed.

The intersections preferably form a triangle, and the angular points of the triangle are made to coincide with points on the surface of the object. Three points suffice to determine a flat plane, this being sufficient for many applications, for instance for monitoring the recovery process or disease progression in the case of a skin disorder.

The device preferably comprises at least one laser, preferably a semiconductor laser, for the purpose of generating at least one of the light beams. A laser can produce a focussed and relatively strong light beam. Semiconductor lasers are small and light and readily available in many forms, and have been found to suffice extremely well in practice. The recording means preferably comprise a digital camera. Digital cameras are also available in many forms, and images in digital form are easier to store, process and send.

The system preferably also comprises of storing, processing and comparing images by means of means provided for this purpose, for instance a PC with suitable software. Changes in the object can thus be determined, recorded and analysed. The system preferably also comprises means for recording data relating to the object or images, and communication means for exchanging data, for instance patient data.

These and other aspects and advantages of the invention will be further elucidated and clarified in the following description of a non-limitative exemplary embodiment of a device according to the invention.

Short description of the figures

The invention is further elucidated hereinbelow on the basis of four figures. Herein: figure 1 shows a perspective front view of an exemplary embodiment of a device according to the invention, mounted on a digital camera; figure 2 shows a perspective rear view thereof; figure 3 shows a demonstration of the use thereof on a patient with a skin disorder, wherein the camera is positioned correctly; and figure 4 shows the same, wherein the camera is not positioned correctly.

Exemplary embodiment of a device according to the invention The reference numerals in the text refer to the components indicated in the figures. Described here as exemplary embodiment is a system for recording and analysis of skin disorders, which consists of a camera 1 with an attached focussing aid 2 according to the invention, in combination with a PC with specialized software (not shown). Camera 1 is used on or by a (home) patient; the PC with software by a (para)rnedical professional of the institution where the patient is being treated. With the system the development of visible skin disorders can be recorded, measured, assessed and shown by processing a number of successive images made over a period of time. The system is also suitable for a once-only recording of a skin disorder, for instance for the purpose of a teleconsultation or second opinion from a fellow-specialist.

The skin is photographed during a first visit to or by the patient. This recording serves as initial reference. Immediately available as recorded image in a first recording is a scale division 3, see figure 3, against which the size of the disorder can be measured without subsequent images. The first recording is entered into the processing program which, in dialogue with the operator, determines the shape and dimensions, and optionally the colour, of the disorder and stores the associated specific settings. This becomes the reference for a subsequent measurement or forms the once-only recording. Photos are once again taken of the disorder during subsequent visits by or to the patient. With correct use of focussing aid 2 these subsequent photos have the same image criterion as each other and as the reference photo and, when the same specific settings are used in the processing program, reliable and accurate measurement and recording of the progression of shape and dimension of the skin disorder through time is possible. The processing program is provided with a module for patient and treatment recording with security means and is prepared for communication with or within care networks. The processing program is provided with a communication module for sending the images or other data of the patient to and from a central point, such as a database, a patient information system or a network of specialists.

The system consists of four main components: a (digital) photo camera 1; - a laser focussing means 2; processing hardware and software; and administrative and communicative software.

Any photo camera can in principle be used, although in the case of analog cameras the images must first be digitized before processing. Laser focussing means 2 consists of a housing for attaching to camera 1 in which six red semiconductor lasers 4 are mounted in three groups of two and shine on the object for photographing. The six light beams can of course also come from fewer than six active light sources, for instance by making use of mirrors. The digital photo camera 1 can optionally also be produced in integrated form with laser focussing means 2, wherein the user-friendliness for particularly older patients is also taken into account. The processing hardware can consist of a normal Personal Computer with an internet connection. The software has the task of analysing and administering the presented images and showing and, if necessary, sending the results.

The focal distance, resolution, light intensity and the convenience of use of the camera are, among others, important factors. These must be sufficient to record the skin disorders with a quality sufficient for assessment. A digital camera is most practical, among other reasons because the data are immediately available in digital form and (administrative, auditive) data can also be added during the recording.

The laser focussing means 2 comprises a housing which can be attached on or to camera 1 and in which three groups of low-power semiconductor lasers 4 with battery supply and control button are mounted. These lasers 4 are arranged such that at a correct recording distance and angle between the "film" surface and the object (determined by once-only calibration), they show three dots 5 on the object, see figure 3, but show one or more double dots 5' at other distances and/or angles, see figure 4. The intention is that the dots 5 are projected onto the skin around an injury or disorder and are visible in the recorded image, among other purposes for subsequent monitoring. The triangle formed by lasers 4 at the correct angle and distance also forms a two-dimensional scale division 3, see figure 3.

The PC has to be able to load the images from camera 1, carry out the processes with the imaging software, carry out the data administration with the administrative software and send the data. By means of, among other processes, colour separation and density discrimination, the processing software calculates or determines the surface area and (if necessary) the shape of the disorder, and compares this to previous recordings of the same disorder of (usually) the same patient. The administrative software administers, among other things, recording data and patient data. The communicative software provides the "tele" aspect and sends and receives images or other data.

The choice of camera 1 is not critical; a good quality digital amateur camera with macro function up to about 0.3 m can suffice. It is useful if additional manual or auditive data input is possible for the purpose of "noting" for instance patient or recording data. In respect of the design and the production of laser focussing means 2, it is preferred to select and recommend one type of camera.

Focussing means 2 is equipped with sufficient small and cheaply available lasers 4 with a red colour. The colours blue and green are somewhat more readily visible on the skin, but these lasers are, at least for the moment, many times larger and more expensive than red lasers. The power of lasers 4 can be chosen well below the value which is acceptable for projection into the eyes.

With the correct direction, distance and angle the three projected dots 5 form a triangle on the body part on which disorder 6 is to be found, see figure 3. In the case of cylindrical or otherwise curved body surfaces a disorder will, as seen from the camera, lie above or below the plane of said triangle. This results in a system inaccuracy which is hi the order of the change in the curve of the body part between recordings. This inaccuracy is however many times smaller than in existing systems of measuring the surface area of skin disorders.

The image processing software is based on methods which are also used in industrial Vision techniques to inspect, among others, the shape, location, position and size of objects. Because industrial vision techniques are generally integrated, non-Open Source systems, are not portable and aimed at a high processing speed, specific software has been developed for the system described here on the basis of, among others, "MatLab". The incoming images are herein separated into the RGB basic colours (RGB) and discriminated per colour into 100% respectively 0% density on the basis of a conversion value set by the operator during the reference recording and thereafter specifically applicable for a patient cycle. The program then calculates the most stable surface and the most certain form of the disorder or injury using special algorithms. Data are subsequently also obtained relating to the reflection properties of the skin surface, and thereby about the structure thereof. The program then shows visually the shape and numerically the surface area of the disorder and, if desired, the surface structure. In addition, the program samples, among other things, the skin colour at a position outside the disorder chosen by the operator, as a reference for lighting conditions during recording.

The administrative software is intended to provide a link to patient recording systems and other networks for and in the healthcare sector. This part of the software comprises the relevant patient and recording data, in addition to a relatively large number of security means to ensure that all data are reliable and correct. This part of the software also comprises and processes the additional data which are or can be stored in the camera, such as identification of the patient, date and time, and data relating to lighting conditions. This part of the software also functions as a database of stored images. The communication part ensures the transmission of images and other data to and from (specialized) networks.

It will be apparent that the invention is by no means limited to the given exemplary embodiment, but that many variants are possible within the scope of the invention. The invention can of course also be used to position two or more random objects relative to each other, wherein intersections of the light beams are made to coincide with determined points in one or more of the objects. The device can herein be coupled to one of the objects, although a standalone arrangement is in principle also possible. All these options fall within the scope of the invention.

Claims

1. Device for positioning recording means for recording images, in particular a digital camera, relative to an object, in particular a body, and more in particular skin, wherein the device can emit light beams, which light beams intersect each other at a plurality of intersections.

2. Device as claimed in claim 1, wherein the intersections form a triangle.

3. Device as claimed in claim 1 or 2, wherein the device comprises at least one laser, preferably a semiconductor laser, for the purpose of generating at least one of the light beams.

4. Device as claimed in any of the foregoing claims, wherein the device also comprises storage means for storing images.

5. Device as claimed in any of the foregoing claims, wherein the device also comprises processing means for processing images.

6. Device as claimed in any of the foregoing claims, wherein the device also comprises comparing means for comparing images.

7. Device as claimed in any of the foregoing claims, wherein the device also comprises recording means for recording data relating to the object.

8. Device as claimed in any of the foregoing claims, wherein the device also comprises recording means for recording data relating to images.

9. Device as claimed in any of the foregoing claims, wherein the device also comprises communication means for exchanging data.

10. Method for positioning recording means for recording images, in particular a digital camera, relative to an object, in particular a body, more in particular skin, wherein the method comprises of emitting light beams by means of a device provided for this purpose, which light beams intersect each other at a plurality of intersections, and positioning the recording means relative to the object using the light beams.

11. Method as claimed in claim 10, wherein the positioning comprises of causing the intersections to at least substantially coincide with determined points in the object.

12. Method as claimed in claim 10 or 11, wherein the positioning comprises of causing the intersections to at least substantially coincide with points on the surface of the object.

13. Method as claimed in any of the claims 10-12, wherein the intersections form a triangle, and the method comprises of causing the angular points of the triangle to at least substantially coincide with points on the surface of the object.

14. Method as claimed in any of the claims 10-13, wherein the method also comprises of storing images by means of storage means provided for this purpose.

15. Method as claimed in any of the claims 10-14, wherein the method also comprises of processing images by means of processing means provided for this purpose.

16. Method as claimed in any of the claims 10-15, wherein the method also comprises of comparing images by means of comparing means provided for this purpose.

17. Method as claimed in any of the claims 10-16, wherein the method also comprises of recording data relating to the object by means of recording means provided for this purpose.

18. Method as claimed in any of the claims 10-17, wherein the method also comprises of recording data relating to recorded images by means of recording means provided for this purpose.

19. Method as claimed in any of the claims 10-18, wherein the method also comprises of exchanging data by means of communication means provided for this purpose.