GB2449855A

GB2449855A - System and method for measuring pupillary distance

Info

Publication number: GB2449855A
Application number: GB0710657A
Authority: GB
Inventors: Steven Harbutt
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-06-05
Filing date: 2007-06-05
Publication date: 2008-12-10
Also published as: GB0710657D0

Abstract

Obtaining a pupillary distance of a user to allow spectacles to be fitted appropriately to a user's face. The method comprises obtaining an image 100 of the user comprising at least one eye on a face, a reference point 170 (such as a pupil), and a scaling reference (200, Fig.2) having a predetermined length. A scaling value is obtained by measuring the scaling reference within the image; obtaining a distance value by measuring the distance between the pupil of the at least one eye 140a and the reference point on the image; and evaluating the pupillary distance using the distance value and the scaling value. A scaling device 355 comprises pointers 365a, 365b and 375a, 375b slidably moveable along the display 310. A network comprising a server and a terminal may be employed to implement the method and allow glasses to be chosen remotely.

Description

Pupillary Distance Measurement System and related Methods

Field of the invention

This invention relates to a pupillary distance measurement system and related methods.

Background of the invention

For spectacles (so-called eye-glasses, or glasses) to be fitted appropriately to a user's face, it is helpful if the pupillary distance of the user is known. This distance is defined as the distance, generally in millimetres, between the pupils of the eyes on the user's face. In many instances this distance will lie between roughly 40 mm and roughly 75 mm. While the pupillary distance of a user is an helpful parameter to know in order to provide an appropriately fitted pair of glasses, this parameter is of greater significance when the glasses to be fitted are so-called multifocal's such as bi-focals, or vari-focals, or the like, as a poorly fitted pair of such glasses will diminish the effectiveness of the lenses.

Previously the pupillary distance has been measured by various means, but most methods are based upon the principle of aligning a user's face to a ruler (or other measurement device) and attempting to read a measurement from the ruler.

One key problem with such previous methods is that it is difficult, without multiple iterations of this process, to obtain accurately the pupillary distance, as each eye of the user is generally, and often unconsciously, moving, whether this be by fixational eye movements, gaze shifting or stabilising, or the like. Therefore, when you measure the location of the first eye, it is likely that this will alter when you move to measure the location of the second eye, thus giving an inaccurate measurement.

A further problem with previous techniques is that is has been difficult to measure the pupillary distance remotely. Thus if a user is unaware of their pupillary distance, it can be difficult for them to purchase remotely, such as by telephone or via the Internet, a pair of glasses that will be appropriately fitted to their face. Those users who perhaps feel this inconvenience more are those whose mobility is impaired, and who cannot travel to an optician for measurement.

Summary of the invention

According to a first aspect of this invention there is provided a method of obtaining a pupillary distance of a user, the method comprising the steps of: obtaining an image of the user comprising at least one eye on a face, a reference point, and a scaling reference having a predetermined length; obtaining a scaling value by measuring the scaling reference within the image; obtaining a distance value by measuring the distance between the pupil of the at least one eye and the reference point on the image; and evaluating the pupillary distance using the distance value and the scaling value.

An advantage of such a method is that by using an image of a user the evaluation of the pupiflary distance can accurately be calculated without the pupils of the user moving. In addition, this method provides for a user to be able to evaluate their own pupillary distance, rather than needing a second person to perform this operation. Such an arrangement is advantageous as it allows a user to evaluate their pupillary distance, at any time, such as when the user is in their own home, etc. Conveniently, the image is a face-on image such that the plane of the face is substantially perpendicular to a line between the device taking the image (e.g. the camera) and the face.

The method may comprise using a scaling device to measure the length of the scaling reference. Subsequently, the length of the scaling reference derived from the image may normalised with the predetermined length to obtain a normalised scaling reference.

Subsequently, the scaling device may be used to measure the distance between the at least one eye and the reference point.

Once the distance between the at least one eye and the reference point has been obtained it can normalised using the normalised scaling reference to obtain a true value of the distance.

The at least one eye on the face, the reference point and the scaling reference, may be arranged in substantially the same focal plane. Such a method may be advantageous, as this may allow the pupillary distance to be easily calculated from the scaling value and the distance value.

However, the at least one eye on the face, the reference point and the scaling reference, may all be arranged on more than one focal plane.

The reference point may be taken to be the pupil of the user's other eye.

Such a method may be advantageous, as the distance value would be directly indicative of the pupillary distance. Alternatively the reference point may be the bridge of the user's nose, or the like. Such an arrangement may exploit the roughly symmetrical nature of a user's face.

For example, in an embodiment wherein the scaling reference is the bridge of the user's nose the distance between the pupil and the bridge of the nose may be doubled to obtain the pupillary distance.

In other embodiments, the pupillary distance may be summed from a set of sub-pupillary distances. For example, the method may measure from a pupil of one eye to the bridge of the nose, from the pupil of the other eye to the bridge of the nose and add these distances.

Two displaced markers may be used to provide the scaling reference. The scaling reference may be displayed on a medium such as a piece of paper, card, plastics material, metal or the like, which may be arranged to be held by the user at the moment their image is captured. The displaced markers may be displaced by roughly 100 mm. The user would be able to read the distance between the markers in the image to obtain the scaling value, and thus normalise this value as being indicative of 100 mm within the image.

The displaced markers may, however, be displaced by roughly any of the following: 500 mm, 250 mm, 80 mm, 50 mm, 25 mm, 10 mm, etc. or any value there between.

Alternatively, the scaling reference may comprise a single, or multiple markers, perhaps of differing or similar geometric shapes. The scaling reference may comprise a line, curve, or any shape, or number of shapes with a known geometry or displacement between markers. Such an arrangement may allow for a scaling value to be obtained based upon a know geometry or displacement within an image The scaling value may be multiplied by the distance value to obtain the pupillary distance. Such an arrangement may provide a simple arithmetic relationship with which to evaluate the pupillary distance.

The method may take an additional measurement from the image which allows spectacles and in particular multifocal spectacles to be fitted to a wearer. It is perhaps more important to fit multifocal spectacles to a wearer so as to help ensure that a wearer looks through the correct part of the lens of the spectacles. This additional measurement may be referred to as a multifocal measurement. The additional measurement may be obtained by measuring between reference points on the image and applying the scaling value to the value obtained from the image.

For example, if spectacles having varifocal lenses are to be fitted the additional measurement may measure the distance on the image between the pupil and a top edge region of the lower frame. As such a first reference point for this additional measurement would comprise the pupil and the second reference point would comprise the top edge region of the lower frame.

In a further example, if spectacles having bi-focal lenses are to be fitted the additional measurement may measure the distance on the image between a top edge region of the lower eyelid and a top edge region of the lower frame. As such a first reference point for this additional measurement would comprise the top edge region of the lower eyelid and the second reference point would comprise the top edge region of the lower frame.

It will readily be appreciated that the term multifocal relates to a plurality of lens arrangements, such as: bifocal, trifocal, quadrafocal, blended segment, progressive, or occupational segment, varifocal, etc. The advantage of obtaining the multifocal measurement is that muUifocal lenses can be accurately fitted to a users face, and thus may help to avoid issues such as headaches, blurry vision, fatigue, nausea, etc. The method may be arranged to obtain additional information, such as bridge size, eye size, etc. This additional information may be evaluated by using further reference points on the image to allow further items to be dimensioned. The scaling value may be used to scale the distance measured from the image.

The method may comprise obtaining a further image of the user. The further image may be a side-view of the user. The side-view may comprise the side of the face, which comprises the bridge of the user's nose and the ear of the user. The side-view may comprise a scaling reference, as described above. The method may then comprise using the location of the bridge of the nose and the location of the user's ear to provide a temple measurement, and obtaining a temple length by evaluating the temple measurement using the scaling reference.

According to a second aspect of the present invention there is provided a measurement system, arranged to evaluate the pupillary distance between two pupils of a user, the system comprising: a display arranged, in use, to display an image comprising at least one eye on face, a reference point, and a scaling reference; a scaling device, arranged, in use to measure a scaling value from a scaling reference and a distance value from a distance between the pupil of at least one eye and a reference point in an image displayed on the screen; and an evaluator, arranged, in use, to evaluate the pupillary distance using the measured distance value and the scaling value.

The display may comprise a first side and a second side, which may have a gap therebetween. The display may comprise an image input system.

This image input system may be an opening provided between the first side and the second side, such that the display is arranged substantially as a pocket. Such an arrangement may be advantageous, as it would allow the user to place an image securely into the display.

The first side may comprise a Window through which the image can be seen. The first side may also comprise the scaling device.

In one embodiment, the scaling device may comprise at least a first pointer, and a second pointer. Each pointer may be associated with a scale, which may be a linear scale.

The scale may be arranged such that a value indicative of the position of the pointers may be readable by a user from the scale. The scale may be arranged such that it provides the distance between the first and second pointers.

In some embodiments, the first and second pointers may be arranged to measure both the scaling value and the distance value. In other embodiments, the scaling device may comprise further pointers. Other embodiments, may also comprise a further scale.

Each pointer of the scaling device may be movable, via a user input system. The user input system may comprise the user's hand. Such an arrangement may be advantageous, as it may allow the user to align manually the pointers with features in the image, such as pupils, reference points, scaling references, etc, and easily read an accurate scaling value and distance value from the scare.

The evaluator may be provided on the rear side of the measurement system. Such an arrangement may be advantageous, as it may allow the measurement system to be used as a compact unit. The evaluator may comprise: a single or plurality of look-up lines; a graphical arrangement, such as a chart or the like; an algorithm, such as an algebraic expression; etc. The measurement system may be manufactured substantially of paper card, plastics material, or the like.

The measurement system may also be implemented electronically. Such an arrangement may be advantageous as it may allow the user to use a digital image, it may be more accurate and it may be possible to perform remotely. In such embodiments, the measurement system may further comprise a storage device arranged to store the digital image, as well as a processing circuitry arranged to process and display the image on the display. In addition a user input system arranged to allow a user to make an input to the system and/or an image input system arranged to allow a user to enter an image to the system may be provided.

Examples of a user input system include any suitable data input system, such as any one, or combination of the following: keyboard; mouse; roller-ball, tablet; touch screen; voice recognition apparatus; text recognition apparatus; joystick; or the like.

Examples of a image input system include any suitable data input system, such as any one, or combination of the following: universal serial bus port; an image scanner, which may be integrated into the measurement system or be peripheral; a magnetic disc drive; a serial and/or parallel port; firewire port; wired or wireless port; Bluetooth receiver; an Internet connection; a network connection; etc. Examples of a display include any suitable display, such as any one, or combination of the following: a Liquid Crystal Display (LCD); a Cathode Ray Tube (CRT) display, a Light Emitting Polymer (LEP) display, or the like.

The processing circuitry may be arranged to cause the display to present other information, such as instructions to the user on how to operate the measurement system, or the like. These further instructions may be on the same display as the image, or may be on an alternative display. If displayed on the same display, the instructions may be displayed in a second window. Such an arrangement may be advantageous as this may allow the user to easily use the system.

In some embodiments, the user input system may be arranged to control the display and may be arranged to control a pointer on the display.

The system may be arranged such that a user can control the scaling device using the user input system.

The processing circuitry may provide the evaluator. In such an embodiment, the evaluator may be arranged to process the position on the display of at least one of the pointers in order to take a measurement.

In other embodiments the processing circuitry may be arranged to allow a user to indicate end regions of the scaling reference. The processing circuitry may allow the user to indicate the end regions using the user input system.

The processing circuitry may also be arranged to allow a user to indicate the position of the pupil of the at least one eye and/or the position of the reference point.

The processing circuitry may be arranged to determine the distance between the at least one pupil and the reference point and/or the length of the scaling reference in pixels. Such an arrangement is convenient and may simplify the normalisatjon of the pupillary distance.

The system may be provided with a database of images of glasses. The database may be arranged such that the user can select a set of glasses from the database. In such an arrangement, the algorithm may be arranged to rotate the image such that the pupils on the image lie on substantially the same horizontal line. Such an arrangement may be advantageous, as this would allow the user to select a pair of glasses frames from the database, and have these glasses scaled by the algorithm and fitted, graphically, to the user's face.

The processing circuitry may be arranged to scale the image of the glasses such they are scaled to be substantially the correct size for viewing on the image.

Further, the processing circuitry may be arranged to place the image of the glasses on the image. Such an embodiment may be useful in allowing a user to see how the glasses would look on his/her face.

According to a third aspect of the present invention there is provided a network, comprising a server and a terminal, wherein the server is in communication with the terminal, and arranged to implement the method of the first aspect of the invention.

Such an arrangement is advantageous as it may allow the remote measurement of pupillary distance.

According to a fourth aspect of the invention there is provided a method of manufacturing a pair of eyeglasses using the method of obtaining the pupillary distance in the first aspect.

According to a fifth aspect of the invention there is provided a machine readable medium containing instructions which when read by a computer cause that computer to perform the method of the first aspect of the invention.

According to a sixth aspect of the invention there is provided a machine readable medium containing instructions which when read by a computer cause that computer to perform as the measurement system of the second aspect of the invention.

According to a seventh aspect of the invention there is provided a server arranged to evaluate a pupillary distance between two pupils of a user comprising; a network connection arranged to receive image data and user input data from the network; a processing circuitry arranged to process the image data and generate display data displaying; the network connection being further arranged to transmit the display data across the network; and the processing circuitry also being arranged to provide an evaluator arranged to determine the length of a scaling reference and a pupillary distance based upon user inputs contained in the input data.

The server may be arranged to accept inputs contained in the input data which comprise a user specifying a point on the image. In particular the points on the image which are specified may be one or more of the following: an end region of a scaling reference on the image; a pupil of an eye and a reference point.

The server may be arranged to accept the points specified as screen co-ordinates.

The server may be arranged to calculate the distance between co-ordinates in order to determine the pupillary distance.

According to an eighth aspect of the invention there is provided a machine readable medium which contains instructions which when read by a machine cause that machine to perform as the server according to the seventh aspect of the invention.

The machine readable medium may comprise any of the following: a floppy disk, a CDROM/RAM, a DVD ROM/RAM (including -RI-RW and RI + RW), a Bin ray disc, an HD DVD, a memory (including a Memory Stick, SD card, Flash memory card or the like), a hard drive, any form of magneto optical storage, a transmitted signal (including an Internet download, an FTP transfer or the like), a wire.

Brief description of the drawings

There now follows, by way of example only, a detailed description of the invention with reference to the accompanying Figures of which: Figure 1 shows a portrait image of a user; Figure 2 shows a portrait image of a user, wherein the image comprises a scaling reference; Figure 3 shows a front side of a measurement system according to a first embodiment; Figure 4 shows a rear side of a measurement system according to a first embodiment; Figure 5 details a flow chart of the steps taken when using a first embodiment of the present invention; Figure 6 shows a second embodiment of the present invention; Figure 7 details a flow chart of the steps taken when using a second embodiment of the present invention; Figure 8 shows a third embodiment of the present invention; Figure 9 shows a fourth embodiment of the present invention; Figure 10 shows a networked embodiment of the present invention.

Detailed description of' the drawings

Figure 1 shows an image 100, such as a picture, of a user's portrait. In particular an image of the user's head 110, which includes his/her face 120. In this image 100, the user's eyes 130a, 130b and corresponding pupils 140a, 140b, are apparent, along with other features of the face 120 such as the ears 145, mouth 150 and nose 160.

Figure 2 shows the image 100 Comprising the user's head 110, as well as a scaling reference 200, which is arranged such that it is positioned with the user at the time the image 100 is captured. The pupillary distance, i.e. the distance between the two pupils, is shown as X for ease of reference.

In the present embodiment the scaling reference 200 comprises two displaced markers 210a, 210b, displaced from one another by a predetermined distance. In this embodiment, the two displaced markers 210a, 210b are displayed on a sheet of paper, which is then positioned at the time the image 100 is captured by the user holding the paper in substantially the same focal plane as the user's eyes 130a, 130b. In the present embodiment the displaced markers 210a, 210b are displaced (in real life as opposed to the represented displacement on the image) by approximately 100 mm.

Figure 3 shows the front side of a measurement system 300 according a first embodiment of the present invention. The system 300 comprises a display 310, arranged to hold an image 100 (such as that shown in Figure 2) in position. The display 310 comprises a first side 320a and a second side 320b, which has a gap therebetween to form a pocket to receive an image. The display 310 has an image input system 330 arranged to allow an image 100, such as a picture, to be introduced between the first and the second sides 320a, 320b. In this embodiment the image input system 330 is an opening between the first side 320a and the second side 320b.

The first side 320a comprises a frame 340 and a window 350 through which an image can be viewed, and a scaling device 355. The scaling device 355 comprises s a first pointer 365a, and a second pointer 365b.

Each pointer 365a, 365b is arranged to be slidably moveable along an upper portion of the display 310. Each pointer may be moved via a user input system, which in this embodiment may be considered as the user's hand.

The scaling device 355 further comprises a numerical reference 365c associated with the position of the pointers 365a, 365b. In this embodiment the numerical reference 365c comprises a linear scale, arranged such that the position of the each pointer 365a, 365b along the upper region of the display 310 correlates to a number, readable by the user from the numerical reference 365c.

The scaling device 355 further comprises a third pointer 375a, and a fourth pointer 375b. Each of the third and fourth pointers 375a, 375b is arranged to be slidably moveable along a lower portion of the display 310. Each pointer 375a, 375b again may be moved via a user input system.

A further numerical reference 375c is associated with the position of the third and fourth pointers 375a, 375b of the scaling device 355. In this embodiment the numerical reference 375c comprises a linear scale, arranged such that the position of each of the third and fourth pointers 375a, 375b along the lower portion of the display 310 correlates to a number, readable by the user from the numerical reference 375c.

Figure 4 shows the rear side of the measurement system 300 of the first embodiment, and thus shows the second side 320b of the display 310. The second side 320b comprises an evaluator 380, which comprises a first look-up line 390a corresponding to the first numerical reference 365c and a second Look-up line 390b corresponding to the further numerical reference 375c. The evaluator 380 further comprises a pupillary distance look-up 390c. In the present embodiment, each look up 390a, 390b, 390c is arranged as a vertical scale, with each scale substantially parallel to one another.

Figure 5 details the steps taken by a user when evaluating his/her pupillary distance using the first embodiment. Firstly 410, the user places the scaling reference 200 with the two displaced markers 210a, 210b of predetermined distance apart in the same focal plane as their eyes 130a, 130b. This may generally be achieved by placing the scaling reference 200 on his/her chin. Secondly 420, the user captures an image 100 of their head 110, which comprises at least one eye 130a and one reference point 170 (but would generally include both eyes), along with the scaling reference 200. It will be readily appreciated by the skilled reader that in this embodiment the user's face 120 should be facing towards the image capturer at the time the image 100 is captured.

In the present embodiment the reference point 170 is the pupil 140b of the other eye 130b. In alternative embodiments, the reference point 170 may be a further point that may be used to evaluate the pupillary distance, such as the bridge of the nose 160, or the like.

Thirdly 430 the user uses the image input system 330 to place the image between the first side 320a and second side 320b of the display 310, such that the one eye 130a, the other reference point 170, and the scaling reference 200 are all visible through the window 350.

Fourthly 440, the user slidably moves the first and second pointer 375a, 375b of the scaling device 355 such that the pointers 375a, 375b are aligned with the displaced markers 2lOa, 210b of the scaling reference in the image 100. In the present embodiment the user then reads the two numbers associated with the positions of the pointer 375a, 375b from the associated numerical reference 375c, and subtracts the smaller from the larger. This resultant number is the scaling value, which is indicative of the known 100 mm distance between the first pointer 375a and second pointer 375b of the scaling measurer 200.

Fifthly 450, the user then slidably moves the third pointer 365a and the fourth pointer 365b of the scaling device 355 such that the pointers 365a, 365b are aligned with the pupil 140a of the one eye 130a and the reference point 170, which in this embodiment is the pupil 140b of the other eye 1301,. In a similar manner to above, user then reads the two numbers associated with the positions of the pointers 365a, 365b from the associated numerical reference 365c, and subtracts the smaller from the larger. This resultant number is the distance value, which is indicative of the pupillary distance of the user as taken from the image.

It will be readily appreciated that the fourth and fifth steps of the present embodiment are not path dependent, and either may be carried out before the other.

Sixthly 460 the user marks the scaling value on the first look-up line 390a of the evaluator 380, and the distance value on the second look-up line 390b on the evaluator 380. The user then linearly extrapolates a line between these marks such until this line dissects the pupillary distance look-up line 390c to evaluate the user's actual pupillary distance; i.e. a pupillary distance normalised using the scaling reference on the image.

In an alternative embodiment still, the evaluator may not be provided with look-up lines, but may be provided with a graphical evaluator 380, such as a chart, which may be arranged to provide the user with their pupillary distance based upon a distance value and a scaling value. In a further alternative embodiment, the user may be provided with an algebraic expression, such that the user may evaluate through their own calculation their pupillary distance.

Figure 6 shows a second embodiment of the present invention. In this embodiment a measurement system 500 comprises a storage device 510 arranged to store an image 550, processing circuitry which includes a processor 520 and a display 530 arranged to display the image 550, as well a user input system 540 and an image input system 560.

In the present embodiment, the display 530, the user input system 540, the storage device 510 and the image input system 550 are all connected to the processor 520. The system 500 further comprises an algorithm, stored on the storage device 510, which is arranged to cause the processor 520 to process information and store information on the storage device 510 and thus implement the present embodiment, as will be described herein.

In this embodiment the image 550 of a user is generally a digital image (similar to the image 100 of the first embodiment) and comprises the samefeatures as the image shown in Figure 2. This digital image 550 is input into the system 500 via the image input system 560 and stored on the storage device 510. In the present embodiment, the image input system 550 comprises a universal series bus port, whereby the algorithm to cause the system 500 to transfer is data associated with the digital image 550 from a peripheral to the storage device 510.

In this embodiment once the image 550 is stored on the storage device 510, the algorithm is arranged to cause the system to display the image 550 on the display 530. The algorithm is arranged to cause the display 530 to present other information, such as instructions to the user on how to operate the system 500, or the like, in a second window 570.

In the present embodiment the display 530 is a Liquid Crytsal Display (LCD), however alternatively, or additionally the display may be any other suitable device such as a Cathode Ray Tube (CRT) display, a Light Emitting Polymer (LEP) display, or the like.

The user input system 540 of the present embodiment is a mouse and graphical pointer 700 arrangement such that movement of the mouse causes the pointer to move. Such an arrangement will be familiar to users of computer systems such as MicrosofttM WIndOwSTM, Mac OSXTM or the like.

The system 500 is therefore arranged such that inputs actuated by the user on the mouse may control the graphical pointer 700 on the display 530. In particular, the algorithm is arranged such that the location of the graphical pointer 700 on the display 530 when a user clicks on the mouse is processed by the processor 520 and recorded on the storage device 510.

It will be readily appreciated to a person skilled in the art that the algorithm may be arranged to cause the display 530 to present the image 550 and a scaling device similar to the first embodiment, wherein the scaling device is represented graphically on the display 410. In such an arrangement the user would be able to graphically move the associated pointers via the user input system 540, to read either values from a scale indicative of displacement, or to allow values to be evaluated by the processor 520 and stored on the storage device 510.

In the present embodiment however the scaling device operates in a different manner. In the present embodiment the processor is arranged to record the location of the graphical pointer 700 on the displayed image 550 at a first mouse click and the location of the graphical pointer 700 on the image at a second mouse click, and to store these values on the storage device 510. The first mouse click gives a position as given by the first pointer in the first embodiment. The second mouse click gives a position as given by the second pointer in the first embodiment.

Similarly, the algorithm is arranged to record the location of the graphical pointer 700 on the displayed image 550 at a third mouse click and the location of the graphical pointer 700 on the image at a fourth mouse click, and to store these values on the storage device 510. The third mouse click gives a position as given by the third pointer in the first embodiment. The fourth mouse click gives a position as given by the fourth pointer in the first embodiment.

The system 500 further comprises an evaluator, however this evaluator is an algebraic function carried out by the processing circuitry, rather than an evaluator that is graphically displayed to the user. In the present embodiment the processor is caused to operate on the location information stored at the mouse clicks to obtain a scaling value (i.e. the distance between the locations of the pointer 700 at the first and second mouse clicks) and a distance value (i.e. the distance between the locations of the pointer 700 at the third and fourth mouse clicks), which are then used to evaluate the pupillary distance.

Figure 7 shows a flow chart outlining the steps taken when implementing the present embodiment, in which in the first step 800 the user places the scaling reference 200 with the two markers 210a, 210b of predetermined distance apart in the same focal plane as his/her eyes 130a, 130b, for example by placing the scaling reference on his/her chin. In this embodiment the distance between the displaced markers 210a, 210b is substantially 100 mm.

Secondly 810, the user captures an image 550 of their head 610, which comprises at least one eye 130a and one reference point 170, along with the scaling reference 200. In the present embodiment the one reference point 170 is the pupil 140b of the other eye 130b.

Thirdly 820 the user inserts the image 550, or the device on which the image 550 is stored, into the image input system 540, i.e. the image may be stored on an external USB memory device, or further external memory device, such as a digital camera.

Fourthly 830, the user causes the processor to process the image, which is arranged firstly to transfer the image 550 to the storage device 510.

The algorithm displays the image 550 on the display 530 as well as a list of instructions to the user as to what subsequent steps are required by the algorithm. Fifthly 840, the user then moves the mouse such that the graphical pointer 700 is positioned over the pupil 140a of the first eye 130a and clicks the mouse (a first location value stored at a first mouse click). This location information is stored on the storage device 510. The user then moves the graphical pointer 700 over the reference point 170, which in this embodiment is the pupil 140b of the second eye 130b, and clicks the mouse (a second location value stored at a second mouse click).

This location information is stored on the storage device 510 also.

In a similar manner to above sixthly 850 the user then moves the mouse such that the graphical pointer 700 is positioned over the first displaced marker 210a of the scaling reference 200 in the displayed image 550 and clicks the mouse (a third location value stored at a third mouse click).

This location information is stored on the storage device 510. The user then moves the graphical pointer 700 over the second displaced marker 210b of the scaling reference 200 in the displayed image 550 and clicks the mouse (a fourth location value stored at a fourth mouse click). This location information is stored on the storage device 510.

The location of each mouse click is stored as a co-ordinate and the algorithm evaluates the displacement by processing the stored co-ordinates.

The displacements can then be stored in the storage device 510 as a scaling value and a displacement value. The processor is then, seventhly 860, arranged to multiply the scaling value by the predetermined distance between the displaced markers 210a, 210b to obtain a virtual scaling value. This virtual scaling value is then multiplied by the distance value to obtain the real pupillary distance.

A third embodiment of the present invention is shown in Figure 8. This embodiment comprises the features of the second embodiment, however this embodiment further comprises a zoom window 900. The display 530 of the present embodiment is arranged to display the zoom window 900, in addition to the image 550.

The zoom window 900 is arranged to provide a zoomed image 910, which is a magnification of the present region on the image 550 of the graphical pointer 700. Is this embodiment the zoomed window 900 is further provided with a reticule-like crosshair 920, arranged such that the user may accurately align the graphical pointer 700, and thus the position when the mouse is clicked, with the relevant region in the image 550.

Figure 9 details a fourth embodiment, which comprises all the features of the second embodiment, and optionally the features of the third embodiment, wherein the system 500 further comprises a database of glasses,stored on the storage device. A line AA is shown on one of the pairs of glasses which comprises an axis of the glasses (or at least a line parallel to an axis of the glasses. In this embodiment, once the pupillary distance has been evaluated the display 530 is arranged to display images of the glasses from the database. Via the mouse and graphical pointer 700 the user is able to select a pair of glasses from the database. In this embodiment, when the further reference point is the other eye, the algorithm is arranged to calculate the required rotation of the image such that the pupils of the user in the image are substantially horizontally aligned with each other. This updated image may then be displayed on the display 550. A person skilled in the art will readily appreciate how to implement such an invention.

Using the real pupillary distance, the algorithm of the present embodiment is then able to scale the selected glasses, such that they graphically fit on the user's face, are able to be displayed to the user as shown in Figure 9b In a fifth embodiment, the invention may be implemented across a network 930 as shown in Figure lOa. In this embodiment there is provided a terminal 940, which may be remote, and a server 950. The server 950 is connected to the terminal 940 via a network connection 951 to a network 930. In this embodiment the server 950 is provided with processing circuitry including a processor 952 and a storage device 954.

The terminal 940 is also provided with a processor 912, as well as an image input system 916, a user input system 918 and a display 960. The terminal may also optionally comprise a storage device 922.

In this embodiment, the server is arranged to operate in a similar manner to previously described embodiments. The storage device 954 of the server is accessed from the terminal 940 via the network 930. The storage device 954 of the server 950 is also provided with a database of glasses as described above. In this embodiment, the user is able to upload their image on to the storage device 954 of the server 950. The processor is then arranged to display the user's image, etc. on the terminal display 960. Similarly, the algorithm is arranged to record and store the inputs made by the user through their user input system 916, and thus calculate the user's pupillary distance. It will be appreciated that the inputs are made by a user on the terminal 940 which generates user input data which is received by the server across the network.

The terminal 940 may implement a similar arrangement to the embodiments described in relation to Figures 6 to 8 wherein the display is provided as a web page or the like. In such an embodiment, the user input data may comprise the screen co-ordinates of the pointer 700 when a user clicks a mouse button (or makes any other suitable input) over one of the end regions of the scaling reference, a pupil or the reference point.

The processing circuitry of the server 952 may subsequently be arranged to calculate the distance between screen co-ordinates to determine the length of the scaling reference and subsequently normalise this measured length with the predetermined length of the scaling reference to obtain a scaling factor. Then the processor may be arranged to measure the length between the pupil and the reference point and apply the scaling reference to this measurement in order to obtain the actual distance between the two pupils.

The skilled reader will readily appreciate how to adapt the previous embodiments to implement such a network 930. It will also be readily appreciated to a person skilled in the art that the network 930 may comprise a LAN, WAN, WiFi, etc connection, or be the Internet or the like. Similarly it will be readily appreciated that the network 930 may comprise a plurality of terminals 940.

Figure lOb shows an arrangement of the network 930, where the server 950 is further connected to a glasses provider 970. The glasses provider 970 in this embodiment may be any provider that can provide glasses, such as a manufacturing system (e.g. milling machine, etc), a warehouse, or retail shop, etc. The algorithm in this embodiment is further arranged to upload additional information from the user, such as name, prescription address etc, and store this on the server storage device 954. The server 950 is also provided with a database of glasses, as described in previous embodiments. Once the user's pupillary distance has been evaluated, the user's details such as address, prescription, frame selection and pupillary distance may then be sent, via the network 930, to the glasses provider 970. The glasses provider 970 may then manufacturer, courier, or reserve for collection, etc, an appropriate pair of glasses for the user.

In alternative embodiments this glasses provider 970 may be connected to the server 950 via an alternative network, or directly. Similarly, any one of the previous embodiments may be arranged to communicate the user's pupillary distance, and optionally other details to a glasses provider 970.

A person skilled in the art will readily appreciate how to implement such an embodiment.

It will also be readily appreciate to the skilled reader that other parameters may be evaluated, such as those required to suitably fit multifocal glasses, or the like. In addition this may comprise the provision of more than one image. A person skilled in the art will readily appreciate how to modify any of the above embodiments accordingly.

In addition it will be readily appreciated by a person skilled in the art that the method and system of any of the given embodiments may be adapted for alternative circumstances. It is envisaged that such as system may be used to measure dimensions in and about the home, such as window dimensions. In such an arrangement the user would be able to purchase suitably sized curtains by using a image comprising a picture of a window and a scaling reference.

Claims

1. A measurement system, arranged to evaluate the pupillary distance between two pupils of a user, the system comprising: a display arranged, in use, to display an image comprising at least one eye on face, a reference point, and a scaling reference; a scaling device, arranged, in use to measure a scaling value from a scaling reference and a distance value from a distance between the pupil of at least one eye and a reference point in an image displayed on the screen; and an evaluator, arranged, in use, to evaluate the pupillary distance using the measured distance value and the scaling value.

2. A system according to claim 1 in which the comprises an image input system.

3. A system according to claim 2 in which the image input system comprises an opening between a first side and a second side of the display such that the display is arranged substantially as a pocket.

4. A system according to claim 3 in which the first side of the display comprises a window through which the image can be seen.

5. A system according to claim 3 or 4 in which the first side of the display comprises the scaling device.

6. A system according to any preceding claim in which the scaling device comprises at least a first pointer, and a second pointer.

7. A system according to claim 6 in which each of the pointer is associated with a scale which is arranged such that it provides the distance between the first and second pointers.

8. A system according to claims 1 which comprises a user input system arranged to control a pointer displayed on the display.

9. A system according to claim 1 or 8 which further comprises a storage device arranged to store an electronic version of an image.

10. A system according to claim 9 which is arranged to cause the display to display an image stored on the storage device.

11. A system according to any of claims 8 to 10 which is arranged to allow a user to indicate end regions of the scaling reference using the user input system.

12. A system according to claim 11 which is arranged to determine the length of the scaling reference using the indicated points of the end regions of the scaling reference.

13. A system according to any of claims 8 to 12 which is arranged to allow a user to indicate the position of the pupil of the at least one eye and/or the position of the reference point using the user input system.

14. A system according to claim 13 which is arranged to determine the distance between the at least one pupil and the reference point using the indicated positions.

15. A system according to any of claims 1 or 8 to 14 which further comprises processing circuitry arranged to provide the evaluator.

16. A system according to any of claims 1 or 8 to 15 which comprises a database of images of spectacles.

17. A system according to claim 16 which is arranged such that a user can select a set of spectacles from the database and display the spectacles on an image displayed on the display.

18. A system according to claim 17 which is arranged such that the image of the spectacles is rotated such that the pupils of the eyes on an image lie on substantially the same horizontal line as an axis of the spectacles.

19. A system according to any of claims 16 to 17 which is arranged to scale the image of the spectacles such they are scaled to be substantially the correct size for viewing on an image displayed on the display.

20. A system substantially as described herein with reference to the accompanying drawings.

21. A method of obtaining a pupillary distance of a user, the method comprising the steps of: obtaining an image of the user comprising at least one eye on a face, a reference point, and a scaling reference having a predetermined length; obtaining a scaling value by measuring the scaling reference within the image; obtaining a distance value by measuring the distance between the pupil of the at least one eye and the reference point on the image; and evaluating the pupillary distance using the distance value and the scaling value.

22. A method according to claim 21 which comprises using a scaling device to measure the length of the scaling reference.

23. A method according to claim 21 or 22 in which the scaling device is used to measure the distance between the at least one eye and the reference point.

24. A method according to any of claims 21 to 23 in which the length of the scaling reference derived from the image is used with the predetermined length to obtain a normalised scaling reference.

25. A method according to claim 24 as it depends from claim 23 in which once the distance between the at least one eye and the reference point has been obtained it is normalised using the normalised scaling reference to obtain a true value of the distance.

26. A method according to any of claims 21 to 25 in which the reference point is taken to be the pupil of the user's other eye.

27. A method according to any of claims 21 to 26 which comprises using two displaced markers to provide the scaling reference.

28. A method according to any of claims 21 to 27 in which the scaling reference is displayed on a medium such as a piece of paper, card, plastics material or metal,

29. A method according to claim 28 in which the medium is held by a user at the moment their image is captured.

30. A method according to any of claims 21 to 29 which takes an additional measurement from the image arranged to allows spectacles having multifocal lenses to be fitted to a wearer.

31, A method according to claim 30 in which the additional measurement comprises measuring the distance on the image between the pupil and a top edge region of the lower frame of the spectacles.

32. A method according to claim 30 or 31 in which the additional measurement comprises measuring the distance on the image between a top edge region of the lower eyelid and a top edge region of the lower frame of the spectacles.

33. A method according to any of claims 21 to 32 which comprises obtaining a further image of the user.

34. A method according to claim 33 in which the further image is a side-view of the user.

35. A method according to claim 33 or 34 in which the further image also comprises a scaling reference.

36. A method according to claim 35 which comprises using the location of the bridge of the nose and the location of the user's ear to provide a temple measurement, and obtaining a temple length by evaluating the temple measurement using the scaling reference.

37. A method of obtaining a pupillary distance of a user substantially as described herein with reference to the accompanying drawings.

38. A network, comprising a server and a terminal, wherein the server is in communication with the terminal, and arranged to implement the method of any of claims 21 to 37.

39. A network substantially as described herein with reference to the accompanying drawings.

40. A server arranged to evaluate a pupillary distance between two pupils of a user comprising; a network connection arranged to receive image data and user input data from the network; a processing circuitry arranged to process the image data and generate display data displaying; the network connection being further arranged to transmit the display data across the network; and the processing circuitry also being arranged to provide an evaluator arranged to determine the length of a scaling reference and a pupillary distance based upon user inputs contained in the input data.

41. A server according to claim 40 in which the user inputs contained in the input data comprise a user specifying a point on the image.

42. A server according to claim 40 which in the user inputs correspond to a user specifying the position of one or more of the following: an end region of a scaling reference on the image; a pupil of an eye and a reference point.

43. A server according to any of claims 40 to 42 in which the user inputs contained in the input data comprise screen co-ordinates.

44. A server according to claim 43 which is arranged to calculate the distance between co-ordinates in order to determine the pupillary distance.

45. A server substantially as described herein with reference to the accompanying drawings.