System and method for measuring and manufacturing

Description

[0001] System and method for measuring and manufacturing

[0002] Technical Field

[0003] The present invention relates to the measuring for and manufacturing of magnifying loupes bespoke for a user. In particular, the present invention relates to providing a system and method for setting of a working distance of a telescope for a loupe and a streamlined holistic method of automating measuring for and manufacturing of magnifying loupes bespoke for a user.

[0004] Background

[0005] In general, a loupe is a small magnification device used to see small details more closely. Typically, ‘loupes’ refers to a binocular pair of magnifying telescopes which are attached to or integrated into a pair of eyeglasses such that they may be worn by a user. Loupes provide a user with magnified vision of a viewing area for extended periods of time without requiring a user’s hands.

[0006] Many professionals such as dentists and surgeons use loupes when performing procedures. Loupes are worn by dentists not only to increase the details that can be seen, but also to improve posture by avoiding slouching to view inside a mouth. Loupes are also common in other healthcare-related professional sectors such as surgery and (typically single eyeglass loupes) in professional sectors such as jewellery, geology and printing.

[0007] Typically, the magnifying telescopes in loupes are ‘straight through’ telescopes, where the eyeline, the first lens and the last lens of the telescope are colinear (such that the path of the light through the telescope is substantially straight). In other cases, the magnifying telescopes are ‘refractive’ telescopes, where each telescope comprises a prism suitable for reflecting light. Refractive telescopes may allow a user to see a viewing area located below them without bending over.

[0008] The alignment and convergence of the telescopes is determined by their relative angle and location to a user’s eyes. Traditionally the bridge of the eyeglasses rests on the user’s nose and the temples of the eyeglasses rest on the user’s ears, where the natural variability between different user’s faces causes the relative location of the telescopes to the user’s eyes to vary depending on the user. This often causes ‘misalignment’ where the user’s eyeline is not coaxial to the principal axis of the telescope’s lenses, instead the user may view the telescopes at an oblique angle. Loupes configured for higher magnifications have a smaller field of view and so any margin for error in the location of the telescopes relative to a user’s eyeline is much smaller. For example, if the interpupillary distance (IPD) is within 1 to 2 mm of the correct distance, lower magnification loupes may still perform effectively for the user. However, for higher magnification loupes, this inaccuracy may lead to the telescopes not performing effectively for that user. For higher magnifications, it therefore becomes more important that the telescopes are positioned correctly for each user.

[0009] Furthermore, misalignment can cause the telescopes to be focussed on different object locations and / or to be out of focus when viewing an object or viewing area, both of which can make the loupes difficult to use for long periods and can cause the user to have headaches or eye strain. Thus, it is desirable to prevent misalignment between the user’s eyeline and the magnifying telescopes.

[0010] Loupes of higher magnifications are preferably made bespoke to each user, in order to improve not only comfort but also to ensure the magnifying telescopes are correctly positioned to ensure efficient magnification for the particular user’s eyes. This process typically requires a series of different steps, requiring the wearing to attend fittings in person, and still often results in the telescopes not being precisely located.

[0011] Aspects and embodiments of the present disclosure have been devised with the aim of increasing the efficiency, accuracy and reliability of loupe manufacturing.

[0012] Summary of the disclosure

[0013] According to a further aspect, there is provided a system for setting of a working distance of a telescope; comprising: a holder comprising a passage, wherein the passage is configured to hold at least part of the telescope, and the holder is configured to exert a force on the held telescope thereby to hold and align the telescope in the passage.

[0014] Preferably, the passage is configured to hold a rotatably adjustable first portion of said telescope, wherein the first portion comprises a first lens.

[0015] In some preferable implementations, the first lens is an objective lens of the telescope.

[0016] In some preferable implementations, the holder may comprise a force-exerting mechanism arranged to exert a constant force on said telescope thereby to hold and align the telescope in the passage, preferably in a mechanical centre of the passage.

[0017] The force-exerting mechanism may be a spring-loaded mechanism.

[0018] The passage may preferably be configured in a shape corresponding to the at least part of said telescope.

[0019] In some preferable implementations, the passage is tapered, preferably wherein the passage is conically shaped. In some preferable implementations, the system comprises an adjustment mechanism configured to adjust the working distance of the telescope held by the holder based on a received signal.

[0020] Preferably, the adjustment mechanism is arranged to rotate the holder based on a received signal such that a first portion of the held telescope is rotated, thereby adjusting the working distance of said telescope.

[0021] The adjustment mechanism may comprise a driver arranged to adjust the working distance of said telescope based on a received signal, preferably wherein the driver is at least one of: a piezoelectric driver; a stepper motor; and / or a servomotor.

[0022] Preferably, the driver controls rotation of a collar, wherein the collar is configured to grip the at least part of a telescope and rotate the at least part, thereby to adjust the working distance of said telescope.

[0023] In some preferable implementations, the system is for setting of a working distance of a telescope for use in a loupe, for example a refractive telescope for use in a loupe.

[0024] According to a further aspect, there is provided a method of setting a working distance of a telescope, the method comprising: arranging a display image in view of a lens of said telescope; arranging an imaging device to capture an image of the display image from a further lens of the telescope; capturing an image of the display image using the imaging device; evaluating the image captured by the imaging device; and adjusting the working distance of the telescope based on the evaluation.

[0025] Preferably, the lens is an ocular lens and the further lens is an objective lens. This can minimize the size of the set-up required.

[0026] The method may further comprise: repeating the capturing, evaluating and adjusting steps until a threshold condition is fulfilled; and preferably fixing the working distance of the telescope once the threshold condition is fulfilled.

[0027] The adjusting the working distance of the telescope may further comprise: sending a signal to an adjustment mechanism for adjusting the working distance of the telescope, wherein the signal is based on the evaluation of the image.

[0028] In some implementations, evaluating the captured image may comprise determining a sharpness of the image.

[0029] In some implementations, the threshold condition may be based on a determined sharpness of the image, preferably wherein the image is a second image and the threshold condition being based on a determined difference in the sharpness of a second image from the sharpness of a first image.

[0030] Preferably, the adjustment mechanism comprises a rotatable collar and wherein adjusting the working distance of the telescope comprises changing a direction of rotation of the collar based on the evaluation.

[0031] Preferably, the display image is positioned at an angle with respect to the lens, for example wherein the display image is positioned at an angle of 45 degrees to the lens. This can mean different parts of the image are at different distances, and so the focus / working distance can be tweaked.

[0032] Preferably, the display image is movable along a rail, the rail being arranged parallel to an axis of the telescope, preferably wherein movement of the display image along the rail is controlled based on the evaluation.

[0033] The adjusting the working distance of the telescope may be actuated using the system as described.

[0034] According to a further aspect, there is provided an apparatus for performing the method as described; the apparatus comprising: a display device configured to arrange a display image in view of a lens of a telescope; an imaging device configured to capture an image of the display image from a further lens of said telescope; a computing device comprising a computer program, wherein the computer program is configured to receive a captured image from the imaging device, and execute the step of evaluating an image captured by the imaging device; and an adjustment mechanism configured to adjust the working distance of said telescope based on a signal received from the computing device, wherein the signal received from the computing device is based on the evaluation of the captured image.

[0035] The apparatus may comprise the system as described above, preferably wherein the further lens is the first lens.

[0036] Preferably, the display image is arranged in an optical path of an ocular lens of a telescope, wherein the imaging device is configured to capture an image from an objective lens of the telescope, and wherein the holder is configured to hold a rotatably adjustable first portion of said telescope, wherein the first portion comprises an objective lens.

[0037] The method of setting a working distance of a telescope, may optionally or alternatively comprise any / all of the following:

[0038] Preferably, the camera has an electronically adjustable focal distance. Preferably, the camera is held a fixed distance away from the telescope. Preferably, the telescopes are held in the jig using a magnetically inter-changeable holder so that it is easy to swap to different telescopes. Preferably, the telescopes once set in the machine are gripped by a motor with a particular gearing ratio to enable fine control.

[0039] Preferably, there is provided a screen on an adjustable rail that is ‘x’ distance away from the telescope. Preferably, this distance ‘x’ is the working distance chosen by the user. Preferably, ‘x’ working distance is chosen by bar code scanning into the machine.

[0040] Preferably, the camera focal distance is calibrated per magnification and interpolated between magnifications. The focal distance being different per magnification and working distance, the calibration step may be necessary although it only has to happen once. The calibration may be performed to ensure what is in focus for the screen / camera is also in focus for the human eye.

[0041] Preferably, upon ‘x’ working distance being chosen by a bar code scanning into the machine, the screen moves to this distance displays a ‘rough focusing’ image. Preferably, the rough focusing image is a series of horizontal black lines separated by a distance. Preferably, the system turns clockwise, pauses and analyses if the contrast (resolution) has increased or decreased. If it has decreased, the system starts to turn counter-clockwise. If it has increased, then it continues turning clockwise.

[0042] Preferably, in the initial rough focus phase, the steps between rotation and analysis are larger to thereby bring the system roughly close to in-focus. Preferably, upon being within a certain limit, the system then fine-focuses so the rotations are smaller. Preferably, if the system overshoots, it then returns back to its determined maximum contrast.

[0043] Preferably, the system holds the telescopes on axis whilst the screws are manually tightened to lock the objective focal distance. Preferably, upon completion, the system is told to release the telescopes.

[0044] According to an aspect, there is provided a system for measuring for and assembling bespoke loupes, comprising: a processor for processing at least one image of a face and determining dimensions, wherein the processor or a further processor is configured for translating the dimensions into assembly instructions; and; preferably further comprising means (preferably in the form of a server with corresponding instructions) for remotely capturing said at least one image of a face.

[0045] According to a further aspect, there is provided a system for remotely measuring for and manufacturing bespoke magnifying loupes. According to a further aspect, there is provided a method of determining a location of a telescope on a frame, comprising: determining or receiving a position of eyes on a face; (preferably determining or receiving at least one of: interpupillary distance; pupillary height; and vertex;); and determining a location of the telescope on the frame with reference to the positions of the eyes on a face.

[0046] In some implementations, the method may further comprise: receiving an image of the face, and determining the position of the eyes on the face using the image.

[0047] In some preferable implementations, the image may be an image of the face wearing a calibration frame, the calibration frame comprising markers of known dimension, and wherein the method may further comprise calibrating dimensions of the image to real dimensions using the known dimensions of the calibration frames.

[0048] The method may further comprise: determining a vertex by triangulation using markers at different depths on the calibration frame relative to a camera, preferably using markers located on side arms of the calibration frame.

[0049] The method may further comprise: calibrating the dimensions of the image with reference to a known real dimension, preferably wherein the known dimension is pupil diameter.

[0050] In some implementations, the eyeline may be a relaxed eyeline, preferably wherein the eyeline is at an oblique angle below a horizontal line.

[0051] In some preferable implementations, the method may further comprise: determining a distance between lenses of the frame and each eye; and determining, using a predefined (e.g. preferably a ‘set’ or ‘optimum’) distance between the eye and ocular lens of a telescope, positioning of the telescope relative to the lens.

[0052] The method may further comprise: determining a diameter of hole to be milled based on the determined positioning of the telescope relative to the lens and a known taper of the telescope.

[0053] According to a further aspect, there is provided a method of manufacturing loupes, comprising: measuring facial dimensions remotely; translating facial dimensions into assembly instructions; and assembling loupes.

[0054] According to a further aspect, there is provided a method of manufacturing a loupe, comprising: receiving at least one image of a face; determining, from the at least one image, facial dimensions; determining, from the at least one image and / or the determined facial dimensions, parameters for loupe manufacture; translating the determined facial dimension and / or the parameters into computer-implementable instructions for a machine, for manufacture of the loupe. The method may further comprise: assembling the loupe using the machine by implementing the instructions.

[0055] The parameters for loupe manufacture may preferably comprise at least one frame parameter, preferably wherein the frame parameter comprises frame shape and / or dimensions.

[0056] The translating may preferably comprise the method as described above and / or the assembling may preferably comprise the method as described above.

[0057] According to a further aspect, there is provided a computer readable non-transitory storage medium comprising a program for a computer configured to cause a processor to perform and / or implement the method as described.

[0058] According to the present disclosure, there is disclosed a system for and method of automating measurement and manufacture of bespoke loupes as a correlated process.

[0059] Any system feature as described herein may also be provided as a method feature, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure. Any, some and / or all features in one aspect of the disclosure may be applied to other aspects of the disclosure, in any appropriate combination or subcombination. In particular, structure aspects may be applied to method aspects, and vice versa.

[0060] It should also be appreciated that particular combinations of the various features described and defined in any aspect of the disclosure can be implemented and / or supplied and / or used independently. The disclosure extends to methods, system and structures substantially as herein described and / or as illustrated with reference to the accompanying figures. The disclosure also extends to any novel aspects or features described and / or illustrated herein. In this specification the word 'or' can be interpreted in the exclusive or inclusive sense unless stated otherwise.

[0061] Furthermore, features implemented in hardware may be implemented in software, and vice versa. Any reference to software and hardware features herein should be construed accordingly.

[0062] The disclosure also provides a computer program and a computer program product comprising software code adapted, when executed on a data processing apparatus, to perform any of the methods described herein, including any or all of their component steps.

[0063] The disclosure also provides a computer program and a computer program product comprising software code which, when executed on a data processing apparatus, comprises any of the apparatus features described herein. The disclosure also provides a computer program and a computer program product having an operating system which supports a computer program for carrying out any of the methods described herein and / or for embodying any of the apparatus features described herein.

[0064] The disclosure also provides a computer readable medium having stored thereon the computer program as aforesaid.

[0065] The disclosure also provides a signal carrying the computer program as aforesaid, and a method of transmitting such a signal.

[0066] The disclosure will now be described, by way of example, with reference to the accompanying drawings.

[0067] Brief Description of Drawings

[0068] In order that the disclosure can be well understood, aspects and embodiments will now be discussed by way of example only with reference to the accompanying drawings, in which:

[0069] Figure 1a is a schematic diagram of an eye looking through a ‘straight through’ loupe;

[0070] Figure 1b is a schematic diagram of an eye looking through a ‘refractive’ loupe;

[0071] Figure 2 shows an overview workflow of the method;

[0072] Figure 3 is a schematic overview of an exemplary system;

[0073] Figure 4 shows a schematic workflow of software processes of the face measuring tool application;

[0074] Figure 5a shows landmark points and then a corresponding mesh overlaid on a schematic camera feed showing a user’s face;

[0075] Figure 5b shows exemplary analysis of landmark points overlaid on a schematic camera feed showing a user’s face;

[0076] Figure 6 shows a schematic illustration of a user’s face wearing calibration reference frames;

[0077] Figure 7 shows an exemplary flow of user interactions with the measuring tool;

[0078] Figure 8 shows an exemplary overview flow of the method of measuring for and assembling bespoke loupes;

[0079] Figure 9a shows a front view of a user’s head wearing the reference calibration frames;

[0080] Figure 9b shows a side view of a user’s head wearing the reference calibration frames;

[0081] Figure 9c shows a top view of a user’s head wearing the reference calibration frames; Figure 9d shows a front view of a user’s head for determining measurements;

[0082] Figure 10 shows a schematic overview of an exemplary CNC machine for manufacturing loupes;

[0083] Figure 11a shows a perspective view of an exemplary CNC machine for manufacturing loupes;

[0084] Figure 11b shows an enlarged view of an exemplary milling tool attachment;

[0085] Figure 12 shows a side view of an exemplary holder for setting a working distance of a telescope;

[0086] Figure 13 shows an exemplary workflow of an automated method of setting a working distance of a telescope; and

[0087] Figure 14 shows an exemplary apparatus for performing the automated method of setting a working distance of a telescope.

[0088] It should be noted that the figures are diagrammatic and may not be drawn to scale. Relative dimensions and proportions of parts of these figures may have been shown exaggerated or reduced in size, for the sake of clarity and convenience in the drawings.

[0089] The same reference signs are generally used to refer to corresponding or similar features in modified and / or different embodiments.

[0090] Detailed Description

[0091] Loupes

[0092] Figure 1a is a schematic diagram of an eye 102 of a user looking through a ‘straight through’ loupe 10, which comprises a ‘straight through’ telescope 108. The eye 102 comprises a pupil 104 and an eyeline 106 (shown as a dashed line in Figure 1a and 1b), where the eyeline 106 is defined as a line originating in the centre of the eye 102 and passing through the centre of the pupil 104. The eyeline 106 is shown as passing through the telescope 108 and onto a viewing area 116. The viewing area 116 is a portion of an object the user is intending to view with magnified vision. For example, if the user is a dentist this may be a portion of a patient’s mouth or teeth.

[0093] The telescope 108 comprises an ocular lens 110, an objective lens 112 and a principal axis 109, where the centre of each of the ocular lens 110 and the objective lens 112 are located on the principal axis 109. It will be understood that light passing through the centre of a lens is not refracted and hence the principal axis 118 represents a path on which light will not be substantially refracted when passing through the telescope. While the telescope 108 is shown comprising only the ocular lens 110 and the objective lens 112, it will be understood that the telescope 108 typically comprises one or more additional lenses, wherein the additional lenses may include lenses for magnification or focusing. Typically, any and / or all lenses in the telescope 108 are arranged such that the centres of said any and / or all lenses are situated on the principal axis. Telescopes may be prismatic or ‘straight-though’.

[0094] The telescope 108 is held in a carrier lens 114, where the telescope is inserted and securely held in an orifice (hole) of the carrier lens 114. As described, typically the carrier lens 114 will be arranged in a pair of eyeglasses such that the telescope 108 and a second telescope are provided in the eyeline of a user (not shown in Figure 1a and 1b). The telescope being ‘securely held’ may encompass multiple methods of attaching the telescope 108 to the carrier lens 114 as will be described below.

[0095] Figure 1 b shows a schematic diagram of an eye 102 of a user looking through a ‘refractive’ loupe 20, which comprises a refractive telescope 120. It will be understood that the arrangement of Figure 1b is substantially similar to Figure 1a (where like reference numerals denote like features) further comprising a refractive prism 118. The refractive prism 118 is arranged to redirect light passing through the telescope 120 (including light passing along the principal axis 109). Advantageously, this may allow a user to view a viewing area 116 which is not directly in their eyeline 106. For example, if the user is a dentist, this may allow the dentist to see a portion of patient’s mouth or teeth without bending forward or looking down. This can be beneficial for a wearer’s back and neck.

[0096] In Figure 1b the refractive prism 118 shown is arranged to cause a 90-degree refraction of light. However, it will be understood that various arrangements of refractive prism 118 are possible. Typically, the refractive prism 118 is a plurality of prisms and / or lenses which may be arranged to cause a refraction of light between 0 and 180 degrees, more typically between 0 and 90 degrees. Furthermore, it will be understood that the path of the principal axis 109 and eyeline 112 through telescope 120 is purely exemplary and will necessarily depend on the arrangement of lenses and prisms within the telescope 120.

[0097] In Figure 1a and 1b, the eyeline 106 is shown as substantially coaxial (shown as parallel in the 2D schematic of Figure 1a and 1b) with the principal axis 109 of the telescopes 108, 120. It will be understood that the user is provided the ‘optimal’ view of the viewing area 116 when the eyeline 106 and the principal axis 109 are coaxial, wherein a user viewing the telescope 108, 120 at an oblique angle to the principal axis 109 may have a reduced field of view through the telescope and hence see a reduced portion of the viewing area 116. Therefore, it can be advantageous to ensure that the eyeline 106 and the principal axis 109 of the telescope 108, 120 are substantially coaxial when in use by a user (e.g. when the loupes 10, 20 are worn by a user). In Figure 1a and 1b the eyeline 106 is shown as perpendicular to the carrier lens 114, however, it will be understood that, as the eyeline 106 is defined by relative location of the pupil 104 to the centre of the eye 102, the direction of the eyeline 106 may vary when the user looks in a different direction relative to the carrier lens 114. For example, the user may have a relaxed eyeline in which the user naturally looks down at an angle to carrier lens 114. Therefore, it may be advantageous to insert and securely hold the telescope 108, 120 at an oblique angle to the carrier lens 114 such that a relaxed eyeline of a user is coaxial with the principal axis 109.

[0098] As described above, a pair of telescopes 108, 120 are typically installed in a pair of eyeglasses, such that one telescope 108, 120 is provided in the eyeline 106 of each eye 102 of a user. Typically, both such telescopes will be arranged to converge at a focal point. Therefore, it will be understood that each telescope 108, 120 in the pair of eyeglasses may be arranged at a different angle such that both may be directed towards the focal point. Typically, said different angles may comprise equal and opposite angles, however it will be understood that natural variability between users may cause eyelines to be non-symmetric and hence the principal axis 109 of each telescope 108, 120 may be arranged at an angle custom to the user such that each principal axis 109 is coaxial with each eyeline 106 and both converge at the focal point.

[0099] Overview

[0100] Presently disclosed is a method of and apparatus for measuring for and manufacturing loupes. In particular, the method and assembly are configured for improving the efficiency and precision with which loupes can be assembled bespoke to a particular user.

[0101] Figure 2 shows an overview workflow of the method. In particular, it comprises the steps of measuring facial dimensions 30, translating those facial dimensions into assembly instructions, 32, and then performing the assembly of the loupes 34. The steps may be performed independently but can advantageously be performed together as a single streamlined and connected method. That is to say, the components are preferably in communication with one another such that the steps of the process follow on from one another in an automated manner. The different stages will be described in detail below.

[0102] Measurement

[0103] Typically, fitting loupes requires a specially trained professional manually taking measurements of an individual’s face in order to ensure an accurate fit. In some instances, measurement of IPD can be performed remotely via analysis of images of a user’s face; however, this can often lead to inaccurate values. The inventors have developed an accurate and efficient tool for and method of remotely obtaining the precise measurements required for fitting loupes, which comprises taking images of a user’s face via a web-based application.

[0104] Obtaining images

[0105] Figure 3 is a schematic overview of an exemplary system for determining measurements of a user’s face remotely by implementing a measuring tool. The computer instructions for implementing the measuring tool instructions are stored in a system server 100. The server 100 sends these instructions over the internet in order to facilitate the running of the measuring tool via a web browser on a remote user device 200. A user at any location can access the tool via the exemplary user device 200 at a remote location. The user device 200 is a computer comprising a processor 202, a memory 204, a storage 206, a communication interface 208, a user interface 210, a camera 212, and (preferably) a speaker 214. These components are coupled to one another by a bus 216. The user device 200 may be a desktop computer, a laptop computer, a mobile phone, tablet or any other computing device. A loupe manufacturing system 1000 is in connection with the server either directly or via an internet connection, so that it can receive instructions implementable by the loupe manufacturing system 1000 to manufacture the loupes. The determined parameters for a particular user may be stored in a database, for example, a cloud-based database; a unique ID for each user can enable different components of a system to access the relevant data. For example, a user may use the app to determine their facial dimensions, which are then stored to the database and the user receives an ID code. The user can then use this code to order the manufacture of bespoke loupes, whereupon the loupe assembly apparatus retrieves the relevant parameters using the code. In some implementations, the application may generate, for example, a quick-response code (QR code), which can be scanned by the manufacturing system 1000 (this may be performed automatically or manually) to receive the relevant parameters for tailoring the manufacture for a particular face.

[0106] The user device 200 of the present invention comprises a camera 212 to enable photos and / or video to be recorded, from which measurements can be determined. The user device 200 accesses the measuring tool via the communication interface 208, and displays it to the user via the user interface 210. The measuring tool requires photographs of the user’s face in order to obtain the required measurements, and so comprises instructions to facilitate access to the camera 212 of the user device 200. Typically a request to access the camera will be output to the user, to which they must agree, before access can be granted. The camera feed from the camera 212 is displayed on the user interface 210 via the web browser window, so that the user can view it and adjust their positioning. Verbal audio instructions may be output to the user via the speaker 214 and / or verbal and / or graphic visual instructions may be output to the user via the user interface 210.

[0107] Figure 4 shows a schematic workflow of software processes of the face measuring tool application. A camera feed 300 from the camera 212 of the user device 200 is duplicated, and a first copy processed locally at the user device 200 and a second copy processed centrally at the system server 100.

[0108] A first process flow 2000 is performed locally on the first copy of the camera feed 300 by the processor 202 of the user device 200, according to instructions sent via communication interface 208 to the memory 204. As a first step, landmarks on a user’s face are determined 2100 in real time. Then, a smoothing filter is applied 2200 to smooth the positions of the landmarks over time to prevent unwanted ‘jitter’ in the display. The landmarks are then used to create an animation of the user’s face 2400, taking the form of a face mesh. The landmarks and the animation are displayed on the camera feed 300 of the user’s face, overlaid in real time when displayed 2500 on the user interface 210 via the browser window.

[0109] Figure 5a shows landmark points and then a corresponding mesh overlaid on a schematic camera feed showing a user’s face, in particular an example of the display 400 showing the user’s head 402 with the landmark points 410 and a further display showing both the landmark points 410 and the face mesh 420 (as determined from the landmark points 410) provided as an overlay. Finally, orientation processing is performed 2600 to ensure the user’s head is in the optimum position, including outputting prompts to a user to correct the positioning. An image is recorded automatically when the user is in the correct position. The correlating frame of the raw camera feed 300, which is sent to the system server 100, is then used to determine the required dimensions via a calibration process.

[0110] A second process flow 3000 is performed on the second copy of the raw camera feed 300 sent to the system server 100. Firstly, the second copy is sent to the system server, 3100, and then calibration processing 3200 is performed. The calibration processing 3200, as will be described in detail later, calibrates the pixel dimensions of the camera feed 300 to real dimensions of the user’s face in order to output the physical measurement dimensions required to manufacture the bespoke loupes 3300. The second process flow 3000 is performed on a second copy of the camera feed 300 to ensure that the calibration processing 3200 is applied to a high resolution, raw version of the images.

[0111] Figure 5b shows exemplary analysis of landmark points overlaid on a schematic camera feed showing a user’s face, specifically an exemplary camera feed 300 of a user’s face 402, over which are displayed the landmark points 410 used for determining facial dimensions of the user’s face. The landmarks points are analysed to determine pixel distances for some of the parameters listed above. In a simple manner, the IPD 424 is defined by a line between a first pupil centre 420 and a second pupil centre 422 (the pupil centres having been defined by the interpolation method as previously described). More precise values for distances between each pupil centre and a defined fixed datum, such as the bridge of the nose, are preferably also determined, to achieve a precise fit for the loupes. Such a distance is known as a monocular pupillary distance, PD, and as there is typically asymmetry in the pupil centre positions, determining the monocular PDs can ensure accurate location of the telescopes on the lenses. The fixed datum may typically be defined using a reference, such as a marker on reference frames, as will be described in a later section. Alternatively, a central point of the nose bridge of a user may be defined, and the monocular PD determined with reference to it.

[0112] In some implementation, further facial dimensions are determined. This can assist in processing to determine a correct orientation of the user’s head. It can also be used to assist in the development of a 3D computer model of the user’s head, so that the dimensions for loupes can be determined based on a model of how the loupes will sit on a user’s head. A selection of such parameters includes the perimeter 430, which is defined, and a line from the top point to the bottom point defines the length 432, while a line from left to right defines the width 434. A left nose to cheek line 426 is provided between a defined left cheek point and a nose point, and similarly, a right nose to cheek line 434 is provided between a defined left cheek point and a nose point. (‘Left’ and ‘right’ in this sense are defined as is viewed on the screen, and, as the user is viewing a mirror image on the screen, this correlates to the user’s ‘left’ and ‘right’.)

[0113] Different methods may be employed for determining the real width of facial dimensions, in other words performing calibration. One approach can be to identify an object which has a known dimension (for example, known width). Such an object may be a calibration marker; for example, specific markers on calibration frames 500 can be used, as shown in Figure 6. These calibration frames 500 are formed akin to eyeglasses, comprising a frame 510 and clear lenses 512. They are sent out to a user, who will place them on their face 600 as they would the loupes, and then undertake the measurement procedure using the measuring tool application. Such a method is illustrated in Figure 7, which shows an exemplary flow of user interactions with the measuring tool, specifically an exemplary workflow of a user interaction with the measurement tool via a web browser. As a first step, the user receives the reference frames 4100. These may, for example, be received by post. The user then puts the frames 500 on (mounts the frames 500 on their face) so that they are wearing them 4200 and opens the measurement tool in a browser window 4300 on their computer device 200 (these two steps could also be performed in the opposite order). Typically, the user will need to grant permission for the measurement tool to access the camera 212 of their user device 200 at step 4400. The measurement tool now displays a live camera feed 300 on the browser window. At step 4500, the user faces the camera 212 front on, looking straight ahead. The browser window displayed on the user interface 210 typically comprises a dot (or other marker) on the screen, on which the user can focus. This can help in assisting the user to stay focused and continue to look straight ahead at the camera 212. The camera feed 300 displayed on the browser window of the user interface 210 should now be showing an image of the user’s face 402. The measuring tool outputs instructions to the user how to adjust their head so that it is at the correct orientation for obtaining the required measurements, and the user positions their head accordingly 4600. This may comprise, for example, moving closer to the camera and tilting their head upwards, upon instructions to do so. Once the user’s head is at the correct orientation, the measurement tool automatically captures the image.

[0114] Figure 6 shows a schematic illustration of a user’s face wearing calibration reference frames.

[0115] The calibration frames 500 comprise a series of reference markers, some of which are formed as a series of marker lines spaced a known distance apart (for example, 100 mm). For example, in the exemplary embodiment shown in Figure 6, there are series of horizontally spaced lines 502 and series of vertically spaced lines 506. Some markers are formed as shapes having differently coloured segments; for example, Figure 6 shows a series of circular markers 504, which have different colour quarters. Additionally, some further markers 508 are provided on the bridge of the frames, which comprise a pattern of different colours. Different colour markers may also typically be provided on each of the arms of the frame 510. The markers have known dimensions which act as the reference object width and height for the purpose of determining the distance between the object and the camera and for calibrating dimensions determined in pixels. By using a series of different markers 502, 504, 506, 508 located at different points on the frames 500 and with different dimensions, any tilt, pitch or yaw, or other distortions can be determined and accounted for. Additionally, using the different colour patterns on markers, the correct orientation can be determined; for example, determining which is the true user’s left and right sides. This can be beneficial as in ‘selfie’ mode, images are often flipped. Real-time processing can be beneficial for performing realtime alignment using the markers.

[0116] Alternative user workflows may not utilize the reference frames 500. For example, the first two steps of Figure 7 may be replaced by a user locating a credit card, which they may hold up to their forehead while facing the camera 4500 and adjusting their orientation 4600. As an alternative object dimension, the diameter across a user’s iris can be used. As there is a consistent value of iris diameter across the population (11.71 mm), this presents a reliable dimension. Additionally, this can be used to determine the distance to the user’s eye, which can aid in achieving an accurate measure for the interpupillary distance (IPD). It can be preferable to use high-resolution images for determinations using the iris diameter, as this is a small dimension relative to a user’s facial features. A high-resolution image is typically defined as having a resolution of at least 300 pixels per inch (PPI) and / or 1 MPx, while preferably a high-resolution image used in the described method has a resolution of at least 5 MPx, more preferably at least 7 MPx.

[0117] In some implementations, a video is recorded of the user moving their head in a set pattern, as directed. For example, the user is instructed to move their head side to side (looking towards their left shoulder and then their right shoulder, or vice versa), thereby adjusting the yaw. They are then instructed to look up and then look down, thereby adjusting the pitch. The calculations of the orientation process, as have been previously described, are applied to the frames of the videos and the parameter values determined for each. The parameter values are tracked over time (for example on parameter value plots over time) and can be mapped to the corresponding image frames. In this manner, the image frames with optimum parameter values can be located from the parameter tracking. These optimum frames can then be extracted and used for calibration and measurement determination. This method can also be useful for determining vertex values using side profile images, which corresponds to the distance between the aperture of the telescopes and the wearer’s eyelid.

[0118] Determining facial dimensions

[0119] Once the required images of a user have been captured, they need to be translated into instructions for one or more machines to perform the assembly. The assembly typically requires milling holes in lenses within a frame to receive telescopes and assembling the telescope on to the lenses.

[0120] Figure 8 shows an exemplary overview flow of the method of measuring for and assembling bespoke loupes, specifically a workflow of the methodology, comprising capturing the images remotely via the measurement tool application 4710, as described above. The method then includes analysing those images 4720, and determining the relevant facial features and dimensions 4730 (for example, the IPD, PH and vertex) . The next step is to translate those dimensions into instructions for the production of the loupes, and translate these into instructions 4740.

[0121] Figures 9a to 9d provide illustration of the methodology by which facial parameters and relevant optical dimensions can be determined from the captured images of a user’s face, and consequently how the positioning and orientation of telescopes 108, 120 within optical loupes 10, 20 can be determined. Figures 9a to 9c indicate a schematic front view, a side view and a top view, respectively, of a user’s head 600 while wearing the calibration frames 500. The images received will typically comprise a front view, as shown in Figure 9a. In some implementations, side views and angles views will also be received (for example, if a video is recorded, as described above). As previously described, the calibration frames 500 comprise a series of markers 502, 504, 506, 508, 510 of known dimension and position, which can be used to calibrate the scale of the images to real world dimensions. In particular, some markers, such as those on the bridge of the nose 508 and arms 510 comprise colour patterns (as can be seen in Figure 9b) - which may simply be black and white - and which can be used to distinguish between the left and right sides. For example, images can be flipped when a camera is in ‘selfie’ mode, and the markers enable the true orientation to be determined.

[0122] Figure 9a shows a front view of a user’s head wearing the reference calibration frames, specifically a schematic example of the image to be analysed, showing a front view of the user’s head 600 wearing the calibration frames 500. The locations of the pupil centres 104-a, 104-b are determined, which can be used to ascertain the interpupillary distance, IPD, and pupillary heights, PH, for each eye. A user’s eyes may not typically be at the same height and so the eyes are measured individually. By measuring the eyes relative to the frame, the eye positions can be calculated and a model of the user created. Using smart triangulation techniques, the vertex (the distance between the user’s eye and the lens) can also be calculated from the front view (as illustrated in Figure 9a). Typically, this comprises using side markers on the arms of the calibration frames 500, which are positioned a bit further to the rear (i.e. a bit further backwards than the markers on the bridge of the frames etc.). The real size of these markers is known, and the relative size to markers at the front to the calibration frames can be determined from the images. In software, using the detected side markers, a virtual ‘3D box’ can be placed, and this used to calculate the vertex. This can, for example, be based on different frames of the user’s face at slightly different angles.

[0123] In one example, the camera 212, as described herein, captures Light Detection and Ranging (LIDAR) data to determine / place said 3D box. LIDAR data can be used to determine a distance between the camera 212 and a point where the light is reflected back to the camera 212, based on the time taken for the light beam (e.g. a laser) to return to the camera 212. A collection of reflection points and their corresponding distances to the camera 212 may be referred to as a ‘point cloud’. Because light can pass through the lenses of the calibration frames 500 (through to the user’s eyes) but cannot pass through the opaque markers 504 on the calibration frames 500, the light from the camera 212 will reflect from the face of a user at different lengths. The distance of the markers 504 from the camera 212 can be subtracted from the distance of the user’s eyes from the camera 212, to determine the distance between the user’s eyes and the markers 504 adjacent the lenses of the calibration frames 500 and thereby calculate the vertex. The distance between the user’s eyes and the lenses may need to be calibrated to account for eyelid thickness and / or lens thickness, for example, by adding or subtracting a known or average value of thickness.

[0124] The same point cloud can be used to determine the other facial measurements, such as PH and IPD, with reference to the markers in a similar way.

[0125] While LIDAR data is typically convenient for a user, as most mobile devices provide a camera capable of capturing LIDAR data, it will be understood that a point cloud may be generated from point data collected by other imaging methods, for example, Radio Detection and Ranging (RADAR), Sound Navigation and Ranging (SONAR) and photogrammetry techniques.

[0126] In some embodiments the user holding the mobile device (comprising the camera 212) may be given instructions by the mobile device in order to increase the accuracy of the generation of the point cloud. The mobile device may instruct a user to move the camera 212 closer to a user’s face than they would typically hold a mobile device (e.g. within 15cm of the user’s eyes), so that, for example, the magnitude of the vertex measurement is larger relative to the distance from the camera 212 to the eye, decreasing the overall error percentage in the vertex measurement. Similarly, locating the camera closer to the user’s eyes increases the accuracy of the IPD and PH measurements.

[0127] In some embodiments, the mobile device may be configured to assist the capturing of LIDAR data by increasing the amount of light reflected onto a user’s face. For example, the mobile device may increase a brightness of the device’s screen and / or display a substantially blank white screen such that more light is reflected or transmitted from the mobile device onto the user’s face.

[0128] Specifically, because the user’s eyeball is rounded / convex, and hence the distance from the camera to the surface of the eyeball is not consistent, the camera 212 is configured to capture multiple points (i.e. multiple points within the point cloud) on the surface of the eyeball to thereby determine multiple distances to the eyeball from the camera 212 and calculate an average vertex. As the number of captured points on the eyeball surface increases (i.e. the density of captured points increases) the accuracy of the average vertex proportionally increases, but the impact of each further captured point on the average vertex decreases exponentially and each increases the time required to process and calculate the average vertex. Therefore, it will be understood that the smart triangulation techniques may determine an optimal number of captured points (typically 6 points) however, based on user input, this number may be increased if greater accuracy is required, or decreased if greater speed is required.

[0129] Figure 9b shows a side profile view of the user’s head 600 wearing the calibration frames 500. A frame of this orientation may be included in the video for analysis.

[0130] Figure 9c shows a top view of a user’s head wearing the reference calibration frames, specifically a top view of the user’s head 600; this may be an included frame, but rarely, and so this is further illustrative of determined dimensions. For example, the locations of the pupil centres 104-a, 104-b can be used to determine the eyelines 106-a, 106-b for each of the eyes and to determine the IPD. The main purpose of the measurements is to determine the real centres of the eyes, in particular relative to the frames 500.

[0131] Figure 9d shows a front view of a user’s head for determining measurements, specifically a further visualisation of eye positions based on the measurements performed, in this case without the calibration frames 500. In some instances, the frames 500 are not used and so the image to be analysed will take the form of Figure 9d. In such a case, the dimensions are determined relative to the user’s face, for example a reference datum point may be defined. In particular, Figure 9d shows a front view visualisation of the user’s head 600. Using the calculated data - in particular based on the positions of the first pupil 104-a and second pupil 104-b, the interpupillary distance, IPD, and pupillary height, PH - the user’s ‘eye positions are saved to the customer’s dataset.

[0132] Determining loupe dimensions and angles

[0133] Now that it has been ascertained where the eyes are, calculations can be performed to determine the location to place the telescopes to achieve optimal vision. All of the customerspecific data can be used to determine the correct positioning for any chosen frame and loupe / telescope type. Depending on the selected frame, the datum points sit higher or lower on the face. As such, different data and parameters and / or calculations may be used to translate the base geometry to the selected frame.

[0134] Once the relevant dimensions (e.g. IPD, PH, vertex) are known, the angles needed for machining can then be calculated. The relevant angles to be determined includes the angle at which the telescopes are rotated towards each other. The telescopes must be angled towards each other such that they ‘converge’ at the focal point (i.e. at the focal length of the lenses). It further comprises the angle at which the telescopes are positioned relative to the frame 42 and the lenses 44. This will depend in particular on the loupes and the telescopes, for example whether refractive telescopes or straight through telescopes are being employed. The downward angle is important as it can provide a more comfortable and convenient position for the eyes, and a better peripheral view. For example, the user’s eyeline when in a ‘relaxed’ state may angle slightly downwards relative to the horizontal. Therefore, it may be advantageous to insert and securely hold a telescope at an oblique angle to the carrier lens 44 such that a relaxed eyeline of a user is coaxial with the principal axis of the telescope.

[0135] The height of the holes 46 to be milled on the lenses 44, which will hold the telescopes in the lenses 44, can be calculated by extrapolating a line from the user’s eyes at the required angle. This is also dependent on the distance the lenses 44 sit away from the eyeballs 102, when the frames 42 are worn by the particular user. This distance is also determinative in calculating the size of the holes 46. The telescopes typically have a tapered body, and so the size of the hole 46 can be used to control where the telescope sits along the horizontal axis. This of course affects how far away the first lens of the telescope sits from the eye 102, and for any particular telescope, there is typically an optimum value for this distance. Therefore, the size of the holes 46 is also calculated in dependence on how the frames 42 sit on a particular user’s face.

[0136] In the particular case in which refractive telescopes are used, two different working distances are calculated. The first working distance relates to where the eyes converge by looking forward into the barrels of the telescopes. The second working distance is the distance where the refractive telescopes align in their optical lines. This should coincide with the location of the object being viewed.

[0137] Measurements and instructions

[0138] Based on the model of the user’s head and the dimensions of the particular loupes and telescopes, the measurements for the assembly of the loupes can be determined. This can include the milling of the holes to receive the telescopes and the assembly itself. Advantageously, the application determines the required measurements and translates them directly into instructions, based on the relationships discussed above.

[0139] Telescope Parameters

[0140] The telescope design involves several critical measurements and increments, and these are closely linked with the dimensions of the hole. As mentioned above, the dimensions of the hole can be changed to alter how the telescopes sit relative to the lenses. These dimensions have a bearing on the configuration and therefore assembly of the loupes. The choice of straight-through or refractive loupes will also be determinative of dimensions and angles for optimally aligned loupes. Below are provided a series of relevant parameters which may occur in various implementations in the determination of the size of the hole (it should not be considered exhaustive, and not all values may be applicable to all implementations): • Length of Taper. The barrel of the telescopes is typically tapered, and the length of the taper can be critical for determining the gradual increase in diameter from the minimum to the maximum. In an exemplary implementation, the taper of the telescope barrel extends over a length of 9.7 mm. Typically the taper of the telescope barrel extends over a length between 5 mm and 5 cm, typically between 9 mm and 2 cm, and most typically approximately 10 mm.

[0141] • Minimum Hole Diameter. The hole diameter must be at least as large as the smallest diameter at the narrowest end of the telescope taper in order that the telescopes can fit within the hole in the lens. In the example, this is 13.14 mm. Typically, this may be between 5 mm and 2 cm.

[0142] • Maximum Hole Diameter. The hole diameter can be no larger than the widest diameter of the telescope, so that the telescope fits within it without falling through. In the example, at the widest end, the taper reaches a diameter of 14.05 mm. Typically, this may be between 10 mm and 3 cm.

[0143] • Factor Increase per Millimeter. This can be useful for calculations determining the diameter of the hole to hold the telescope at a particular depth within the hole. The rate of increase in the hole diameter per millimetre of the taper is calculated by the formula:

[0144] Maximum Hole Diameter — Minimum Hole Diameter 14.05 — 13.14 Increase per mm = - - — - - = -

[0145] Length of Taper 9.7

[0146] • Lens Thickness: The lens within the telescope has a thickness. In the present example, it is 2 mm.

[0147] • Maximum Hole Diameter Considering Lens Thickness: As the lens, within which the hole is to be milled, has a thickness of its own, this can mean that the maximum diameter of the hole may need to be updated so that the telescope can be held at the correct position. This is typically also dependent on whether the milled hole is to be cylindrical or tapered, as this determines where the telescope will fit within the hole. In the present example, when factoring in the lens thickness, the maximum hole diameter remains 14.05 mm.

[0148] • Distance from Eye to Barrel: This refers to the distance between the eye and the start of the telescope barrel. This may typically change for different telescopes. According to the present example, this value is 10 mm. Typically, this may be between 5 mm and 3 cm. The size of the hole is determined based on the how the frames sit on a user’s face, and the size of hole required to hold the telescopes such that they sit at the correct distance from the eye to barrel (eye to the first lens of the telescope).

[0149] In some implementations, the rim of the hole is tapered (rather than cylindrical) in order to accommodate snugly and precisely the tapered telescope barrel. This taper can be determined using the values above. This taper is typically configured to accommodate the telescopes at an angle with respect to the horizontal and / or the telescopes being placed at an angle convergent to one another.

[0150] Baseline parameters

[0151] The ‘baseline parameters’ are determined and populated by the face scanning and measuring application (‘the app’) and passed from the application to the assembly rig. This may be achieved by scanning a QR code generated by the app, which contains the relevant baseline parameters. The baseline parameters are used for the telescope design and operation, and are defined by the following terms as parameters for the equations which follow:

[0152] • Downward Angle: downward_angle

[0153] • Vertex Distance: vertex_di stance

[0154] • Segment Height Left: segment_height_left

[0155] • Segment Height Right: segment_height_right

[0156] • Segment Height: segment_height

[0157] • Pupil Distance Left: pupil_distance_left

[0158] • Pupil Distance Right: pupil_distance_right

[0159] • Tool Diameter: tool_diameter

[0160] • Working Distance: working_distance

[0161] • Convergence Factor: convergence_factor

[0162] • Convergence Distance: convergence_distance

[0163] Further parameters can be defined for a particular telescope and its assembly rig. By way of a particular example, these parameters may be:

[0164] • Centre Eye Cornea Distance: 11 mm

[0165] • Frame Adjust Offset: 4 mm

[0166] • Eye Telescope Offset: 10 mm

[0167] • Baseline Eye Pivot A: 25.72 mm

[0168] • Baseline Eye Pivot B: 24.7 mm (‘Baseline Eye Pivot A and B’ are the distances from the eye positions in relation to the pivot / centre points of the machines.)

[0169] • Datum X Start: 0 mm • Datum Y Start: -1.3566 mm

[0170] • Degrees Per Millimeter: 1.58506 deg / mm

[0171] • Start Movement Push in X Position: -25 mm

[0172] • Push Rod Diameter: 6 mm

[0173] Datum and Offset Calculations

[0174] The parameters can be input into the following equations (written below in the format of computer instructions, using the terms as defined above) to perform the calculations for the datum and offset:

[0175] • Distance from Eye to Working Distance: distance _eye_to_wd

[0176] = centre _eye _cornea_distance + conver gence -distance

[0177] + vert ex -distance

[0178] • Left Hypotenuse (the direct line between the left pupil and the working distance): hypoth_left = f (pupil_distance_left )2+ (distance_eye_to_wd)2

[0179] • Right Hypotenuse (the direct line between the right pupil and the working distance): hypoth_right = y (pupil_distance_right )2+ (distance_eye_to_wd)2

[0180] • Left Angle: angle _left = degrees(atan2(pupil_distance_left, distance _eye_to_wd)

[0181] • Right Angle: angle_right = degrees(atan2(pupil_distance_right, distance _eye_to_wd

[0182] • Left Translation Corrected:

[0183] • Right Translation Corrected:

[0184] • Datum X Left Centre Eye (the centre point for milling the hole for the left eye telescope): datum_x_left_centre_eye = (pupil_distance_left — translation_left_corrected) — 1

[0185] • Datum X Right Centre Eye (the centre point for milling the hole for the left eye telescope): datum_x_left_centre_eye = pupil_distance_right — translation_left_corrected

[0186] • Centre Eye to Glass: ance cent

[0187] Downangle

[0188] / downward_angle downangle _sin_x_32 = sin - ^7; -

[0189] 180

[0190] Correction Y Axis Left correction_y_axis_left

[0191] Correction Y Axis Right: correction_y_axis_right

[0192] = segment _height_right + downangle _sin_x_32

[0193] / downwar d_angle \

[0194] + Sin ( - 777 - 7T )

[0195] 180

[0196] Y Position Centre Eye Left: y_pos_centre_eye_left = datum_y _start + correction_y_axis_left

[0197] Y Position Centre Eye Right: y_pos_centre_eye_right = datum_y_start + correction_y_axis_right

[0198] Adjusted Y Position Based on Frame Shape (the positioning is dependent on the structure and arrangement of the frames themselves):

[0199] Convergence Calculations

[0200] Telescope convergence can be programmed by defining parameters according to the following equations (again, written in the form of computer instructions):

[0201] • Telescope Front End Length Internal: telescope_front_end_length_internal = (e. g. ) 22.24 mm

[0202] • Telescope Prismatic Angle: telescope_prismatic_angle = (e. g. ) 45.08°

[0203] • Telescope Working Distance: telescope_working_distance = working -distance • Telescope Distance Prism Eye: telescope -distance prism_eye

[0204] = telescope_front_end_length + centre_eye_cornea_distance

[0205] + eye_telescope_offset

[0206] • Telescope Hypotenuse Left: telescope_hypot_left = f (anglejeft)2+ (telescope_distance_prism_eye)

[0207] • Telescope Hypotenuse Right:

[0208] > telescope_hypot_right = g (angle _right)2+ (telescope_distance_prism_eye)

[0209] • Telescope Distance Left Due to Convergence Angle:

[0210] • Telescope Distance Right Due to Convergence Angle:

[0211] • Telescope Left Datum X Corrected: telescope_left_datum_x_corrected

[0212] = pupil_distance_left — translation_left_corrected

[0213] — telescope_distance_left_due_conv_angle

[0214] • Telescope Right Datum X Corrected: telescope_right_datum_x_corrected

[0215] = pupil_distance _right — translation_right_corrected

[0216] — telescope_distance_right_due_conv_angle

[0217] • Telescope YAW Distance Left: telescope_YAW _distance_left

[0218] = pupil_distance_left — telescope_distance_left_due_conv_angle

[0219] • Telescope YAW Distance Right: telescope_YAW _distance_left

[0220] = pupil_distance_left — telescope_distance_left_due_conv_angle

[0221] • Telescope Left Yaw Angle: telescope_left_y aw _angle

[0222] = degrees(atan2(telescope_YAW _distance_left, telescope -Working -distance)')

[0223] • Telescope Right Yaw Angle: telescope_right_yaw _angle

[0224] = degrees(atan2(telescope_YAW_distance_right, telescope -Working -distance))

[0225] • Telescope Left X Push Aligner: telescope_left_yaw_angle telescope_left_x_push_aligner = - - - degrees_per_mm

[0226] • Telescope Right X Push Aligner: telescope j ght_yaw_angle telescope_right_x_push_aligner = - - - degrees_per_mm

[0227] • Telescope G-Code Angle Correction: telescope_g_code_angle_correction

[0228] = —push_rod_diameter — telescope_left_x_push_aligner

[0229] • Polar Transition Right X: polar _transition_right_X

[0230] = datum_x_right_centre_eye — 30 telescope_right_yaw_angle \

[0231] ■ sin - n

[0232] \ 180 J

[0233] • Polar Transition Right Y:

[0234] • Polar Transition Left X:

[0235] • Polar Transition Left Y:

[0236] • Z-Cut Height: if prescription needed: z_cut_height = (e. g. ) 48; else z_cut_height = (e. g. ) 50

[0237] Spiral Cut Calculations

[0238] A ‘spiral cut’ is used to mill the hole in the lenses, within which the telescopes are fitted. The spiral cut determines the diameter of the hole which is cut in dependence on the best positioning of the telescopes within the lenses so that the distance between the eye and the telescopes is optimal. This diameter is determined in dependence on the taper of the telescope, and so at what depth the telescope sits within the hole. The spiral cut can be defined according to the following equations (again, written in the format of computer-implementable instructions):

[0239] Telescope Depth: telescopedep= distance _vertex + frame_correction_offset

[0240] — telescope_distance_eye_to_barrel

[0241] • Parser Taper Distance - this determines the size of the hole required dependent on where the telescope must sit relative to the eye: if distance _vertex > 26 then par ser -taper -distance

[0242] = telescope_max_hole_diameter_comp_lens_thickness if distance_vertex < 16 then parser -taper -distance = telescope_min_hole_diameter if 16 < distance _vertex < 26 then parser -taper -distance

[0243] = (telescope_depth — telescope_distance_to_barrel

[0244] + telescope_lens_thickness) ■ telescope_factor_increase_per_mm

[0245] • Final Cutter Diameter: final_cutter_diameter = parser_taper_distance

[0246] • Adjusted Parser Taper Distance: adjusted_par ser -taper -distance

[0247] = par ser _tap er -distance — tool_diameter_global — 0.10

[0248] (In this case, a slight adjustment is optionally added to accommodate for a tighter press fit; in this case, this is 0.10, but may take other values)

[0249] • Spiral Cut Radius: spiral_cut_radius = (e. g. ) 0.0

[0250] • Datum X Spiral: if loop_index = 0 then datum_x spiral = spiral_cut_radius ■ 2 else if loopjndex = 2 then datum_x spiral = — 1 ■ (spiral_cut_radius ■ 2) else datum_x_spiral = spiral_cut_radius ■ 2

[0251] Feedrates

[0252] The instructions may further comprise defining particular feedrates for the manufacturing equipment, including the free space feedrate, dimple cut feedrate, dimple cut mill feedrate, plunge feedrate, mill feedrate, positioning feedrate, pushing feedrate, telescope glue feedrate. By way of example, these may be defined as follows:

[0253] • Free Space Feedrate: 5000 mm / min

[0254] • Dimple Cut Feedrate: 2500 mm / min

[0255] • Dimple Cut Mill Feedrate: 75 mm / min

[0256] • Plunge Feedrate: 125 mm / min

[0257] • Mill Feedrate: 150 mm / min

[0258] • Positioning Feedrate: 150 mm / min

[0259] • Pushing Feedrate: 200 mm / min Telescope Glue Feedrate: 50 mm / min

[0260] Manufacture - CNC Machine

[0261] Figure 10 shows a schematic overview of an exemplary CNC machine for manufacturing loupes, specifically a schematic diagram of a loupe manufacturing system 1000 comprising a Computer Numerical Control (CNC) machine 1010, which is configurable in a plurality of modes, and a plurality of attachments associated with the plurality of modes, according to an embodiment of the present invention. As shown in Figure 10, the CNC machine may be configured in a milling mode 1012, where the milling mode 1012 is associated with one or more milling attachments 1012a.

[0262] Generally, a ‘mode’ refers to a set of software and / or hardware operations made by the CNC machine 1010 to facilitate a process during the manufacturing of a pair of loupes. The loupe manufacturing system 1000 typically comprises a computer device connected to the CNC machine 1010 suitable for ‘controlling’ the mode of the CNC machine. It will be understood that controlling includes commands such as, but not limited to, selecting one of the plurality of modes; executing software associated with one of the plurality of modes, terminating software associated with a plurality of modes and changing or altering the one or more attachments currently in use by the CNC machine.

[0263] Typically, the computer device may be internal to or attachable to the CNC machine, however, it will be understood that the CNC may comprise a receiver for receiving commands and the computer device may comprise a transmitter for transmitting commands and wherein the computer device is an external device or a cloud-based device such that, effectively, the CNC machine may be controlled remotely.

[0264] In some embodiments the computer device may provide an input method such that a (human) operator may manually control the mode of the CNC machine 1010 via the computer device. Typically, the changing or altering the one or more attachments is enacted via an operation of the hardware of the CNC machine 1010. For example, an attachment holder arm of the CNC machine 1010 may be rotated to change the active attachment from a first milling attachment to a second attachment. However, in some embodiments, the changing or altering the one or more attachments may be performed manually by a human operator. In such embodiments the loupe manufacturing system 1000 may provide a prompt to the human operator that a manual attachment change is required. Said prompt may include one or more of: a visual prompt, such as a light or a display screen; an audible prompt such as an alarm, bell or recorded message (played via a speaker); and a digital prompt, which may be transmitted via the computer device to an operator’s mobile or computer device. It will be appreciated that numerous methods for prompting a human operator may be implemented with the loupe manufacturing system 1000.

[0265] Milling Mode

[0266] Figure 11a shows a perspective view of an exemplary CNC machine for manufacturing loupes, specifically a schematic diagram of the loupe manufacturing system 1000 comprising a CNC machine 1010 configured in a milling mode 1012. The CNC machine comprises an ‘Add-on box’, which provides a further Input / Output (I / O) controlled by the machine code. The CNC machine 1010 comprises a spindle apparatus 1002 which is moveable along the X direction by means of being mounted on an X-rail 1020. The spindle apparatus comprises a spindle motor 1100 with a driveshaft, wherein the driveshaft is connected to a spindle arm 1102, which extends out from the spindle motor 1100 in the Z-direction and is extendable / moveable along the Z-axis. The spindle motor 1100 is configured to rotate the spindle arm 1102 around the Z- axis. A milling attachment 1104 is connected to the spindle arm 1102 at an end distal the spindle motor 1100 such that the spindle motor 1100, spindle arm 1102 and milling attachment 1104 may effectively act as a drill.

[0267] The CNC machine 1010 further comprises a Y-platform 1004, which is moveable along the Y- axis as it is mounted on a Y-rail 1022. The Y-platform comprises a first stage 1024, which supports a platform arm 1106, which extends outwardly from the first stage 1024 in an X- direction. The first stage 1024 lies in the Y-Z plane and is rotatable around the X-axis, thereby forming the ‘A-axis’ of the CNC machine. The platform arm 1106 comprises a second stage 1108 which lies in the X-Z plane and is rotatable about the Y-axis (which is normal to the surface of the platform arm 1106). The second stage 1108 therefore provides the ‘B-axis’ freedom of movement of the CNC machine. As shown in Figure 11a, a jig 1100 is connected / attached to the second stage 1108 proximate its centre. The jig 1110 is configured to hold a carrier frame 1112, as illustrated, the carrier frame 1112 comprising two carrier lenses 1114a, 1114b.

[0268] Figure 11a shows that the spindle arm 1102 is movable in two translational degrees of freedom relative to the jig, specifically translatable along an X-axis and a Z-axis. The jig 1110 itself is movable in two rotational degrees of freedom and one translational degree of freedom, specifically rotatable in an A-axis and a B-axis and translatable along a Y-axis. Hence the CNC machine 1010 allows the jig 1110 to move relative to the spindle arm 1102 in 5 degrees of freedom. It will be appreciated that the specific configuration of the CNC is exemplary, and the degrees of freedom between the spindle arm 1102 and the jig 1110 may be implemented in an alternative manner. In some implementations, a CNC machine with 6 degrees of freedom may alternatively be used. The CNC machine 1010 is configured to facilitate the milling of a hole in one or each of the carrier lenses 1114a, 1114b such that a telescope may then be inserted into said hole(s) for manufacturing a pair of loupes. The 5 degrees of freedom provided by the CNC machine 1010 can allow the milling attachment 1104 (located at the distal end of the spindle arm 1102) to be brought into contact with a carrier lens 1114a, 1114b at any relative angle and relative position.

[0269] Figure 11 b shows an enlarged view of an exemplary milling tool attachment, specifically a schematic diagram of a magnified view of a portion of the CNC machine 1010. Specifically, Figure 11b shows the milling attachment 1104 connected to the distal end of the spindle arm 1102 (typically a long tool holder is used as the spindle arms 1102). As illustrated, the milling attachment 1104 can be brought into contact with the carrier lens 1114a. The carrier lens 1114a is affixed within the carrier frame 1112. The carrier frame is 1112 held in place by the jig 1110.

[0270] It will be understood that the term ‘milling’ refers to any / all of drilling, cutting, carving, grinding or abrasing of a carrier lens such that a hole or orifice is created. Typically, the carrier lenses 1114a, 1114b are made of glass and thus the milling attachment is preferably a tool suitable for milling glass. However, it will be appreciated that in some embodiments carrier lenses 1114a, 1114b may be made of other materials, for example, acrylic plastic. In such embodiments, the milling attachment is preferably a tool suitable for milling the material of the lenses, for example plastic. A kit of milling attachments suitable for different materials may be provided as part of the loupe manufacturing system 1000. Figures 11a and 11b show the milling attachment 1104 already partially inserted into one of the carrier lenses 1114a, 1114b. It will be understood that this depicts an intermediate stage of the milling process after an initial incision has been made by the milling attachment 1104.

[0271] It will be understood that the three translational degrees of freedom of relative motion between the spindle arm 1102 and the jig 1110 allow the milling attachment 1104 to mill a substantially cylindrical hole of any size and at any location through the surface of the carrier lens 1114a. The size of said cylindrical hole may be varied by altering the size of the milling attachment or by moving the milling attachment in a circular pattern so as to widen a smaller cylindrical hole (i.e. a ‘spiral cut’ pattern). The two rotational degrees of freedom of relative motion allow a central axis of said cylindrical hole to be milled at any angle in the range 0 to 90 degrees relative to a normal of the surface 1118 of carrier lens 1114a. This is shown in Figure 11 b where a central axis 1120 of the milling attachment 1104 (which is coaxial with the driveshaft of the motor 1100) is oblique to the normal of a surface 1118 of carrier lens 1114a and thereby is arranged to mill a cylindrical hole at an oblique angle. This can facilitate the mounting of the telescopes at an oblique angle. Furthermore, the two rotational degrees of freedom of relative motion also allow the milling attachment to mill a hole in carrier lens 1114a in the shape of a conical frustrum, wherein the diameter of the cylindrical hole tapers along the central axis of the cylinder. The diameter may taper in a direction towards or away from the spindle arm 1102. Advantageously, this may improve the ability to affix a telescope to one or each of the carrier lenses 1114a, 1114b, by milling a tapered hole corresponding to the taper of the telescope barrel, as will be described below.

[0272] Automated setting of working distance of a telescope

[0273] Accurate setting of the working distance of telescopes and in particular telescopes for use in loupes is challenging. Adjustment of the working distance is often controlled by rotation (screwing in and out) of a first portion of the telescope that comprises the objective lens of the telescope. The working distance is determined by the separation distance between the lenses in the telescopes: the smaller this distance, the larger the working distance. As such, the positioning of the objective lens can affect the working distance. The accuracy of the setting of the working distance is often limited by the threads of the telescope associated with the rotation of this first portion.

[0274] Whilst the working distance adjustment threads are machined to be fine, for example threads of size M 12 x 0.5 mm are common, there is still some inevitable play in these threads which means that the objective lens may be not precisely positioned. This can be problematic when the working distance of the telescope is being set.

[0275] For example, in a telescope with M 12 X 0.5 mm 4h 6G adjustment threads the angular play of the threads can reach up to 3 degrees and the linear play can be up to 0.3 mm. This play in the adjustment threads can result in inaccurate setting of working distance.

[0276] A holder for use in setting a working distance of a telescope seeks to address this problem. The holder is configured to hold at least part of a telescope in a passage of the holder, where the passage extends through the holder. The holder is configured to exert a force on the telescope held within it to retain the telescope in the passage, for example using a force exerting mechanism (this may be a resilient mechanism, for example comprising springs). An example of such a holder is shown in Figure 12.

[0277] Figure 12 shows a side view of an exemplary holder for setting a working distance of a telescope. The holder 6000 of Figure 12 is for use in setting a working distance of a telescope 8000, in particular for holding a telescope securely and facilitating fine tuning of positioning of the objective lens, to thereby fine tune the working distance of the telescope. The telescope 8000 as illustrated is a refractive telescope, and hence the holder is configured for a refractive telescope.

[0278] In the example holder as illustrated in Figure 12, a force is exerted onto the held telescope 8000 by a spring-loaded holding mechanism 6100 i.e. the holder 6000 is a spring-loaded holder. The spring-loaded holding mechanism 6100 may comprise a single spring but more typically comprises at least two springs. The spring-loaded holding mechanism 6100 exerts a constant spring force (or pressure) that holds the telescope 8000 within a recess 6200 of the holder, thereby pushing the telescope 8000 into passage 6200 of the holder 6000. The force exerted by the holder 6000 on the held telescope 8000 is preferably symmetrical such that it holds the telescope 8000 in the mechanical centre of the passage 6200. The spring-loaded holding mechanism 6100 is arranged to exert a constant spring force in a direction towards the passage 6200, as indicated by the ‘spring’ arrow in Figure 12. The objective end 8300 of the telescope 8000 (the end at which the objective lens 8400 is located) is positioned within the recess 6200. The set / grub screws holding the lens within the telescope are accessible whilst under tension and aligned in the holder 6000, which allows the lens to be unscrewed such that its position can be adjusted and then fixed once in the correct position has been found.

[0279] The recess 6200 has a shape designed for the telescope 8000, such that the telescope 8000 fits snugly and securely within the recess 6200. In particular, the passage 6200 has a complementary shape to at least a portion of the telescope 8000 in order to hold it securely. Further, the recess 6200 has a tapered conical shape. The springs 6100 push the telescope 8000 towards the taper of the recess 6200, having the effect of securely holding the telescope 8000 in position. This typically prevents both translation and angular movement of the telescope 8000 within the recess 6200. In particular, this has the effect of keeping the telescope 8000 in a mechanical central position, so that it therefore remains optically aligned. This maintains the alignment of the held telescope 8000 throughout the setting of the working distance, thereby reducing or eliminating misalignment that might occur because of accidental movement of the telescope 8000.

[0280] It will be appreciated that other methods of exerting a pressure / force on the telescope are possible and the spring-loaded mechanism 6100 shown in Figure 12 is one possibility. The spring-loaded holding mechanism 6100 may be replaced with another functionally equivalent force exerting mechanism that holds or resiliently holds telescope 8000 in passage 6200. For example, a force exerting mechanism that acts to “pull” the telescope 8000 into passage 6200 is also possible. In some embodiments, the holder 6000 is removably attachable to the adjustment mechanism 7000, such that the telescope 8000 being adjusted may be interchanged more rapidly by replacing a first holder 6000 and telescope 8000, with a second holder 6000 and telescope 8000, without needing to reinsert the telescope 8000 into a holder 6000. Typically, the holder 6000 may be attached / connected to the adjustment mechanism 7000 using one or more magnets, which are configured to maintain the holder 6000 in alignment with the adjustment mechanism 7000 by magnetic forces, but which can be disconnected from the adjustment mechanism 7000 by a user by manually overcoming the magnetic forces (e.g. by pulling the holder 6000 away from the adjustment mechanism 7000).

[0281] Figure 12 shows the objective portion 8300 of the telescope 8000 held in passage 6200. The holder 6000 is typically configured such that rotation of the holder 6000 rotates the objective portion 8300 held in the passage 8200 relative to the rest of the telescope 8000. The objective portion 8300 comprises the objective 8400 of the telescope and is in connection with the rest of the telescope 8000 via adjustment screw threads 8200. Rotation of the first portion 8300 (to screw it in and out of the rest of the telescope 8000) therefore moves the objective lens 8400 relative to the ocular lens at the ocular end 8100 of the telescope 8000. This has the effect of adjusting the working distance / focal plane of the telescope 8000. Rotation of the holder 6000 rotates the held portion of the telescope 8000 in this example the first portion 8300.

[0282] In particular, the holder comprises an adjustment mechanism 7000, as shown in Figure 12, configured to adjust the working distance / focal plane of a telescope 8000 held by a holder based on a received signal for example an electrical or wireless signal. The adjustment mechanism may be used to reduce the time required to accurately set the working distance of a telescope 8000 and may be used to automate the process of setting the working distance. The adjustment mechanism may be implemented with holder 6000 or with other holders.

[0283] In more detail, the adjustment mechanism 7000 comprises a piezoelectric rotary driver arranged to adjust the working distance / focal plane of said telescope based on a received signal. In this particular example, the piezoelectric rotary driver comprises and controls a collar or ring 7100 which forms the inner surfaces of the passage 6200 of the holder 6000. The rotary piezoelectric driver 7000 comprises arms 7200 configured to rotate the collar 7100. The collar 7100 is configured to grasp the holder 6000 such that rotation of the collar 7100 causes rotation of the holder 6000. This is typically facilitated by the friction fit provided by the springloading, as described above. Rotation of the holder 6000 in turn rotates the held portion of the telescope 8000 - in this example the objective portion 8300 - thereby adjusting the focal plane of the telescope 8000 by moving the objective lens 8400 to set the working distance. The rotary piezoelectric driver 7000 typically has a high gearing ratio such that the movement of the rotor can be finely controlled. The piezoelectric driver 7000 typically can control rotation of the collar 7100 clockwise and anticlockwise to an accuracy of at least 0.05°.

[0284] The signal to control the adjustment mechanism may be generated by and received from a control device or computing system 10000 that is automated or that is controlled by a user setting the working distance.

[0285] To set a working distance of a telescope using the example shown in Figure 12, the objective portion 8300 of the telescope is placed in the complementary shaped passage 6200 of the holder 6000 and is held in position in the centre of the passage 6200 by means of spring- loaded mechanism 6100, which exerts a constant spring force on the telescope 8100.

[0286] An image is arranged in the view (optical path) of the ocular end 8100 of the telescope 8000 and the image is viewed through the objective lens 8400 of the telescope 8000. The objective lens 8400 of the telescope is visible through the end of the passage 6200 of the holder 6000. The image may be viewed by eye or using an image detector. This can typically be viewed at approximately 15 mm from the objective lens. If the working distance alignment were to be performed the other way around - namely by viewing from the ocular end 8100 - then the target would need to be located at approximately 350 mm from the objective lens 8400. By setting the working distance in this configuration, the required apparatus arranged can be made much smaller. It should be understood, however, that the holder 6000 and adjustment mechanism 7000 could still be implemented in a similar manner to adjust the working distance even if the telescope were oriented the other way around.

[0287] The working distance of the telescope 8000 is adjusted based on an evaluation of the image: for example, a property of the image for example the sharpness of the image. Typically, the working distance is adjusted by rotating (screwing in and out) the objective end 8300 of the telescope relative to the rest of the telescope 8000, which moves the objective lens 3400 relative to the ocular lens. This is achieved by actuating the piezoelectric driver 7000, which provides precise control over the rotations. For example, a user may use a control device 10000 to send an electrical signal, based on the evaluated image, to adjustment mechanism 7000 or an electrical signal may be sent automatically by a computing system based on the evaluation of the image. On receipt of the electrical signal the adjustment mechanism adjusts the working distance / focal plane of the telescope based on the electrical signal. In the example shown in Figure 12 an electrical signal is sent to the rotary piezoelectric driver 7000 which rotates collar 7100 a set number of degrees clockwise or counterclockwise based on the received electrical signal. The rotation of the collar 7100 causes rotation of the objective portion 8300 (screwing it in or out), thereby adjusting the working distance of the telescope 8000. Once an adjustment has been made, the image is viewed again and further adjustments made (e.g. iteratively) until predefined criteria are met. For example, the criteria may comprise a threshold sharpness for the image. The criteria may relate to the desired working distance of the telescope 8000 and / or a calibration point from which the working distance can be reliably set using a known rotation of the front portion or known adjustment of the lead screws of the telescope.

[0288] The setting of the working distance using a holder, such as that described above, can be performed manually or can be automated. Manual setting of the working distance of a telescope can be time consuming and labour intensive. It is also important to achieve good accuracy, and sometimes manual setting can be subjective and based on the eyesight of the setter. An automated method that reduces the time to set the working distance, reduces the labour involved, and provides good accuracy is therefore desirable.

[0289] Figure 13 shows an exemplary workflow of an automated method of setting a working distance of a telescope, specifically an automated method 11000 of setting a working distance of a telescope (such as a telescope for use in loupes as described above).

[0290] Figure 14 shows an exemplary apparatus for performing the automated method of setting a working distance of a telescope, specifically an apparatus 9000 for performing the automated method 11000 of setting a working distance of a telescope.

[0291] The method 11000 comprises arranging a display image in view of (i.e. in the optical path of) the ocular (eyepiece) of the telescope 11100 and arranging an imaging device to capture an image of the display image from an objective lens of the telescope 11200. The imaging device is arranged to view the display arranged on the eyepiece side of the telescope through the objective lens of the telescope. The method further comprises the imaging device capturing 11300 an image of the display and an evaluation 11400 of the captured image. The working distance of the telescope is then adjusted 11500 based on the evaluation of the captured image.

[0292] The capturing 11300, evaluating 11400 and adjusting 11500 steps may then be repeated until a threshold condition for the evaluation that represents a calibration point is fulfilled.

[0293] The evaluation of the captured image may be performed by a computing device running a programme to evaluate one or more properties of the captured images. The one or more properties may then be compared to threshold conditions. For example, the computing device may receive a captured image from the imaging device and evaluate the sharpness of the captured image. The sharpness can be evaluated for example by considering the rise distance of a pixel, a group of pixels or the pixels of the entire captured image. The programme then compares the determined sharpness to a threshold condition for example a threshold data set corresponding to a calibration image. The threshold value or calibrated image may be chosen based on the desired working distance. If the threshold condition is not met, then the working distance / focal plane of the telescope is adjusted. The magnitude of the adjustment of the working distance / focal plane of the telescope may be based on the evaluation of the captured image; for example, if the evaluated one or more properties is far removed from the threshold condition, then a larger adjustment to the working distance / focal plane may be instructed by the computing device. On the contrary, if the evaluated one or more properties is close to the threshold condition, then a relatively smaller adjustment to the working distance / focal plane may be instructed by the computing device. The focal plane / working distance may be adjusted to be closer to or farther from the objective of the telescope i.e. , the working distance / focal length of the telescope may be increased or decreased.

[0294] The step of adjusting the working distance / focal plane of the telescope may be automated by sending a signal to an adjustment mechanism for adjusting the focal plane of the telescope, wherein the signal is based on the evaluation of the image. In more detail, a computing device may receive an image captured by imaging device. The computing device then evaluates the captured image as above and sends a signal to the adjustment mechanism based on this evaluation of the captured image. The adjustment mechanism may preferably be the adjustment mechanism 7000 described in detail above and the telescope may be held by a holder such as the holder 6000 described in detail above.

[0295] The working distance / focal plane of the telescope may be fixed once the threshold condition is fulfilled (the calibration point reached). The set / grub screws are accessible whilst under tension and aligned in the holder 6000 and so can be actuated (e.g. manually tightened) to fix the positioning - and consequently the working distance. The holder 6000 may comprise a manual or electronic release button / switch, to allow removal of the telescope from the holder 6000. This release button may be triggered automatically by an input to the computer device, as described below.

[0296] Alternatively, in some implementations, if the threshold condition corresponds to a calibration point then once the telescope is calibrated, the working distance may be set by a known rotation of the first portion of the telescope a certain number of degrees clockwise or counterclockwise using, for example, the telescope’s lead screw based on the desired working distance. Once this final adjustment is made the working distance / focal plane of the telescope may be fixed.

[0297] The programme running on the computing device may contain these fine-tuning instructions / final adjustment instructions to be performed once calibration has been achieved (the threshold conditions met). The fine-tuning instructions may be based on a predefined desired working distance entered by the user or contained on reference data set on the computing device.

[0298] The automated process 11000 greatly increases the speed at which the working distance of a telescope can be set. Typically, this can be performed within 1 minute.

[0299] In some instances, the telescopes may not be manufactured sufficiently accurately to perfectly align (meaning that even after aligning the optical path with the mechanism described above, there may still be a slight optical misalignment). In such a case, the ring on the objective-side 8300 ring can also be manipulated automatically based on the camera-display setup after setting the working distance, such that it is pushed in the correct optical centre (even if the mechanics are slightly off). This is prior to setting the grub screws, and once in the correct position, the grub screws can be tightened to fix the position and alignment.

[0300] Figure 14 shows an apparatus 9000 for performing the automated method 11000 of setting a working distance of a telescope 8000, which will now be described in detail. The apparatus 9000 comprises: a display device 12000; an imaging device 13000; a holder 6000 and an adjustment mechanism 7000, both as described above; and a computing device 10000. The display 13000 is configured to show a display image in an optical path (in view) of the ocular 8100 of a telescope 8000 for which the working distance is to be set. The display device 12000 may be electronic or non-electronic. In the example shown in Figure 14 the display device 12000 is electronic and comprises a controllable pixel screen. The display device 12000 is positioned in view of the ocular end 8100 of the telescope 8000. The properties of the pixel screen may be programmable to display different images.

[0301] It will be understood that a multitude of focusing images (calibration images) exist, which may be used to validate or evaluate the resolution and / or sharpness of the image detected by the imaging device 13000. However, in a preferred embodiment the display device 12000 comprises a series of horizontal black lines separated by a regular interval distance on a white background. This arrangement of colour contrast advantageously allows a repeatable and efficient means to quantify the sharpness / resolution detected by the imaging device.

[0302] The display device 12000 is positioned at an angle to the ocular end 8100 of the telescope, in particular in the illustrated embodiment, the display 12000 is positioned at 45° to the optical path of the ocular end 8100 of the telescope 8000. This means that different portions of the display 12000 are at different distances from the ocular end 8100.

[0303] It will be understood that varying the distance of the display 12000 from the ocular end 8100 may be achieved by other means. For example, in some embodiments the display 12000 is arranged perpendicular (i.e. substantially 90°) to the optical path and attached to a rail arranged parallel (i.e. substantially 0°) to the optical path, where the display 12000 is configured to be movable along the rail - and fixable at points along the rail - to thereby allow the display 12000 to be set at given distance from the ocular end 8100. In particular, this allows the display 12000 to be arranged at the desired / intended working distance from the ocular end 8100. In some embodiments, the movement of the display 12000 along the rail may be motorised and controllable via the computing device 10000.

[0304] The desired / intended working distance is input to the apparatus 9000 by the user. In some embodiments, the computing device 10000 may, for example, provide a keyboard or touchscreen for inputting the intended working distance value. However, in a preferred embodiment, the user generates a bar code using the smart triangulation techniques, as described above. The barcode encodes the intended working distance value (and optionally other parameters such as IPD and PD) and may thereby communicate the working distance to the computing device 10000 via a barcode scanner connected to the computing device 10000. Advantageously, this may allow the working distance to be more quickly and accurately transmitted to the computing device 10000, with reduced human error. Upon receipt of the input of the intended working distance (e.g. via the barcode or keyboard input means) the apparatus may trigger the movement of the display 12000 along the rail to the intended working distance.

[0305] The imaging device 13000 is configured to capture an image from an objective lens 8400 of the telescope 8000. That is to say the imaging device 12000 is configured to perform the capturing step 11300 of method 11000.

[0306] The imaging device 13000 may for example be a camera, a charge-coupled device (CCD) etc. In the example shown in Figure 14 the imaging device is a camera 13000, with an electronically adjustable focal distance (as described below), positioned in front of the objective of telescope, at a fixed distance away from the telescope 8000. The imaging device 13000 may take a continuous image (a video) of the display image or may take discrete images of the display image.

[0307] Telescopes typically comprise multiple magnification options. The optimal focal distance varies per magnification option and also depends on the intended working distance (as inputted by the user). Therefore, the adjustable focal distance is initially calibrated per magnification and interpolated between magnifications. The calibration ensures that the imaging device 12000 is aligned with the focal length of the human eye of the user.

[0308] As discussed previously, locating an imaging device 13000 at the objective end 8300 of the telescope 80000 and receiving through the objective lens 8400 an image of a display on the eyepiece side 8100, means that the apparatus 9000 can be made to be more compact than if convention were followed and the positions of the display device 12000 and imaging device 13000 were reversed. However, the method can also be performed with a telescope the other way around. In some implementations, the movement of the lead screw may refer to a screw near the ocular. In some implementations, the display and imaging device may simply be provided at the other ends of the telescope.

[0309] The computing device 10000 comprises a computer program, wherein the computer program is configured to receive a captured image from the imaging device 13000, and is configured to execute the step 11400 of evaluating an image captured by the imaging device. A processor may be part of a computing device. The computing device is in communication with the imaging device to receive captured images and may also control capture of the images by imaging device. The computing device 10000 may preferably instruct the imaging device 12000 to perform the capturing step 11300. The computing device 10000 is also in communication with the adjustment mechanism 7000. The computing device 10000 is configured to send a signal to the adjustment mechanism 7000 based on the evaluation of the captured image. For example, the computing device 10000 may send an electrical signal or wireless signal to the adjustment mechanism 7000.

[0310] The apparatus 9000 comprises a holder 6000 and adjustment mechanism 7000, for example the holder 6000 and adjustment mechanism 7000 described above and shown in Figure 12. In the example, shown in Figure 12, a refractive telescope 8000 for use in a loupe is held in passage 6200 of holder 6000 by means of a spring-loaded mechanism 6100 which exerts a constant spring force on the telescope 8000 that acts to “push” (hold securely) the objective portion 8300 into the passage 6200 of the holder 6000. The passage 6200 is shaped to receive the objective portion 8300 of the telescope 8000. The objective portion 8300 of the telescope fits snugly in the passage 6200 of the holder 6000. The objective portion 8300 comprises the objective lens 8400 and adjustment threads 8200 of the telescope 8000.

[0311] The example adjustment mechanism 7000 shown in the apparatus of Figure 14 is identical in structure and function to the adjustment mechanism 7000 described above. The adjustment mechanism 7000 comprises a piezoelectric rotary driver arranged to adjust the working distance / focal plane of the refractive telescope 8000 based on a signal received from the computing system 10000.

[0312] The piezoelectric rotary driver 7000 comprises and controls a collar 7100 or ring which can be positioned around and grasp the objective portion 8300 of the telescope 8000. The rotary piezoelectric driver 7000 is configured to rotate the collar 7100. This causes adjustment of the working distance / focal plane of the telescope by moving the objective lens 8400 relative to the ocular 8100 to set the working distance.

[0313] The display device 12000 comprises a controllable pixel display arranged in the view of the ocular 8100 of the held refractive telescope 8000. The pixel display is positioned at an angle to the ocular 8100, for example a 45 degree angle. By placing the pixel display at an angle, the depth and thus the ideal centre of focus can be determined from an image captured by imaging device 13000. The display 1200 may typically be located at a distance of 10 mm to 12 mm (typically 8 mm to 20 mm) from the ocular 8100.

[0314] The imaging device 13000 is a camera shown in Figure 14. The camera 13000 is positioned to capture an image of the display from the objective lens 8400 of the held telescope 8000. The imaging device 13000 can be placed very close to the objective lens 8400, even right up against (i,e. , directly adjacent to) the lens.

[0315] As noted above, by using camera 13000 to view the display image on the eyepiece side of the telescope the apparatus can be made to be more compact than if the positions of the display and camera were reversed, as is conventional.

[0316] A computing device 10000 is used to control the apparatus 9000 and further automate the method 11000 of setting a working distance of the telescope 8000. The computing device 10000 communicates with and controls the display device 12000, camera 13000, and the piezoelectric rotary driver 7000. The computing system 10000 runs a computer program wherein the computer program is configured to receive a captured image from the imaging device 13000, and executes the step of evaluating 11400 an image captured by the imaging device of method 11000.

[0317] In more detail, the computing device 10000 instructs the camera 13000 to a capture an image of the display and send to the computing device 10000 the captured image of the display. The computing device 10000 receives the captured image from the imaging device 13000 and evaluates a property or properties of the captured image; in this example, this comprises the sharpness of the captured image. The analysis may comprise considering the rise distance of a pixel, a group of pixels or the pixels of the entire captured image. The computing device 10000 then compares the determined property or properties to a threshold condition, for example a threshold data set corresponding to a calibrated image. The threshold value or calibrated image may be chosen based on the desired working distance. If the threshold condition is not met, the computing device sends a signal to the piezoelectric driver to adjust the working distance / focal plane of the telescope. The magnitude of the adjustment of the working distance / focal plane of the telescope 8000 may be based on the evaluation of the captured image, for example if the evaluated one or more properties is far removed from the threshold condition, then a larger adjustment to the working distance / focal plane may be instructed by the processor. On the contrary, if the evaluated one or more properties is close to the threshold condition, then a relatively small (or smaller) adjustment to the focal plane may be instructed by the processor. Likewise, the working distance / focal plane may be adjusted to be closer to or farther from the objective of the telescope i.e. the focal length of the telescope may be increased or decreased.

[0318] A further control element allows operation of the lead screw 8200 of the telescope 8000 by the computing system 10000: this allows for fine-tuning or final setting of the working distance by rotation of the objective portion 8300 of the telescope 8000 by a certain number of degrees clockwise or counterclockwise via movement of the telescope’s lead screw 8200.

[0319] The apparatus 9000 may be secured to an optical table.

[0320] The apparatus 9000 of Figure 14 will now be described in use for the automated setting of a refractive telescope for use in a loupe.

[0321] A refractive telescope 8000 is loaded into the passage 6200 of the spring-loaded holder 6000 and held in place by a constant spring force. The controllable pixel display 12000 is angled in view of the ocular 8100 of the telescope 8000 and displays a pre-set image. The camera 13000 is aligned with the objective lens 8400 of the held refractive telescope 8000. The computer device 10000 controls the camera 13000 to take an image of the display image through the objective lens 8400 of the telescope 8000. The captured display image is sent to the computing device 10000 from the camera 13000. The computing device 10000 receives the captured image and evaluates the sharpness of the captured image. The sharpness of the captured image is compared to a threshold value or condition which corresponds to a calibrated image. The threshold value or calibrated image may be chosen based on the desired working distance. If the threshold value or condition is not met then the computing device 10000 sends a signal, in this case an electrical signal, to the piezoelectric rotary driver 7000. The piezoelectric rotary driver 7000 receives the signal and initiates a rotation based on the received signal. The rotation of the rotary piezoelectric rotates the collar 7100, which rotates the objective portion 8300 of the held telescope 8000 relative to the ocular 8100, thereby adjusting the working distance / focal plane of the telescope 8000 based on the signal provided by the computing device 10000.

[0322] In some embodiments, the computing device 10000 a difference in the sharpness of the of the captured image. Specifically, by comparing a current captured image to a previous captured image, the computer device 10000 can calculate a magnitude and parity of the difference in sharpness and base don’t he difference alter the operation of the adjustment mechanism 7000 (e.g. increase / decrease the rotation amount of the collar, and or / the direction of rotation). For example, the computer device 10000 may calculate a -5% decrease in the sharpness of the image and thereby reverse the direction of rotation of the collar, as the previous movement reduced the sharpness, and decrease the rotation amount, as the overall rotation caused a proportionally large change in the sharpness. In this way, the computing device 10000 and adjustment mechanism 7000 can be used to locate an optimal sharpness of the captured image as viewed through the telescope.

[0323] The computing system 10000 then instructs the imaging device 13000 to capture another image and the capturing, evaluating and adjusting steps are repeated until a set threshold value or condition is satisfied. The working distance / focal plane of the telescope 8000 may be fixed once the threshold condition is fulfilled (the calibration point reached) and the refractive telescope 8000 removed from the holder 6000.

[0324] Alternatively, once a calibration condition has been achieved a final adjustment of the working distance may be made. The working distance may be further fine-tuned by rotating the objective portion of the telescope a certain number of degrees clockwise or counterclockwise using the telescope’s lead screw. The computer software may be pre-set with fine-tuning instructions based on a value of the desired working distance. Once the final adjustment is made the working distance / focal plane of the telescope may be fixed and the refractive telescope with the desired working distance set removed from the holder.

[0325] It will be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.

[0326] Reference numerals appearing in the claims are by way of illustration only and shall have no limiting effect on the scope of the claims.

Claims

CLAIMS1. A system for setting of a working distance of a telescope; comprising: a holder comprising a passage, wherein the passage is configured to hold at least part of the telescope, and the holder is configured to exert a force on the held telescope thereby to hold and align the telescope in the passage.

2. The system of claim 1 , wherein the passage is configured to hold a rotatably adjustable first portion of said telescope, wherein the first portion comprises a first lens.

3. The system of claim 2, wherein the first lens is an objective lens of the telescope.

4. The system of any preceding claim, wherein the holder comprises a force-exerting mechanism arranged to exert a constant force on said telescope thereby to hold and align the telescope in the passage, preferably in a mechanical centre of the passage.

5. The system of claim 4, wherein the force-exerting mechanism is a spring-loaded mechanism.

6. The system of any preceding claim, wherein the passage is configured in a shape corresponding to the at least part of said telescope.

7. The system of any preceding claim, wherein the passage is tapered, preferably wherein the passage is conically shaped.

8. The system of any preceding claim, comprising an adjustment mechanism configured to adjust the working distance of the telescope held by the holder based on a received signal.

9. The system of claim 8, wherein the adjustment mechanism is arranged to rotate the holder based on a received signal such that a first portion of the held telescope is rotated, thereby adjusting the working distance of said telescope.

10. The system of claim 8 or 9, wherein the adjustment mechanism comprises a driver arranged to adjust the working distance of said telescope based on a received signal, preferably wherein the driver is at least one of: a piezoelectric driver; a stepper motor; and / or a servomotor.

11. The system of claim 10, wherein the driver controls rotation of a collar, wherein the collar is configured to grip the at least part of a telescope and rotate the at least part, thereby to adjust the working distance of said telescope.

12. The system of any preceding claim, wherein the system is for setting of a working distance of a telescope for use in a loupe, for example a refractive telescope for use in a loupe.

13. A method of setting a working distance of a telescope, the method comprising: arranging a display image in view of a lens of said telescope; arranging an imaging device to capture an image of the display image from a further lens of the telescope; capturing an image of the display image using the imaging device; evaluating the image captured by the imaging device; and adjusting the working distance of the telescope based on the evaluation.

14. The method of claim 13, wherein the lens is an ocular lens and the further lens is an objective lens.

15. The method of claim 13 or 14, comprising: repeating the capturing, evaluating and adjusting steps until a threshold condition is fulfilled; and preferably fixing the working distance of the telescope once the threshold condition is fulfilled.

16. The method of any of claims 13 to 15, wherein adjusting the working distance of the telescope comprises: sending a signal to an adjustment mechanism for adjusting the working distance of the telescope, wherein the signal is based on the evaluation of the image.

17. The method of any of claims 13 to 16, wherein evaluating the captured image comprises determining a sharpness of the image.

18. The method of claim 17, wherein the threshold condition is based on a determined sharpness of the image, preferably wherein the image is a second image and the threshold condition being based on a determined difference in the sharpness of a second image from the sharpness of a first image.

19. The method of any of claims 13 to 18, wherein the adjustment mechanism comprises a rotatable collar and wherein adjusting the working distance of the telescope comprises changing a direction of rotation of the collar based on the evaluation.

20. The method of any of claims 13 to 19, wherein the display image is positioned at an angle with respect to the lens, preferably wherein the display image is positioned at an angle of 45 degrees to the lens.

21. The method of any of claims 13 to 19, wherein the display image is movable along a rail, the rail being arranged parallel to an axis of the telescope, preferably wherein movement of the display image along the rail is controlled based on the evaluation.

22. The method of any of claims 13 to 21 , wherein the adjusting the working distance of the telescope is actuated using the system of any of claims 1 to 12.

23. An apparatus for performing the method of claims 13 to 21 ; the apparatus comprising: a display device configured to arrange a display image in view of a lens of a telescope; an imaging device configured to capture an image of the display image from a further lens of said telescope; a computing device comprising a computer program, wherein the computer program is configured to receive a captured image from the imaging device, and execute the step of evaluating an image captured by the imaging device; and an adjustment mechanism configured to adjust the working distance of said telescope based on a signal received from the computing device, wherein the signal received from the computing device is based on the evaluation of the captured image.

24. The apparatus of claim 23, comprising the system of claims 1 to 12, preferably wherein the further lens is the first lens.

25. The apparatus of claim 24, wherein the display image is arranged in an optical path of an ocular lens of a telescope, wherein the imaging device is configured to capture an image from an objective lens of the telescope, and wherein the holder is configured to hold a rotatably adjustable first portion of said telescope, wherein the first portion comprises an objective lens.

26. A system for measuring for and assembling bespoke loupes, comprising:a processor for processing at least one image of a face and determining dimensions, wherein the processor is configured for translating the dimensions into assembly instructions; and a machine configured for assembling loupes based on receiving the assembly instructions, preferably further comprising means for remotely capturing said at least one image of a face, preferably the means for capturing comprises a server with corresponding instructions.

27. A method of determining a location of a telescope on a frame, comprising: determining or receiving a position of eyes on a face; and determining a location of the telescope on the frame with reference to the positions of eyes on a face.

28. The method of claim 27, further comprising: receiving an image of the face, and determining the position of the eyes on the face using the image.

29. The method of claim 28, wherein the image is an image of the face wearing a calibration frame, the calibration frame comprising markers of known dimension, and wherein the method further comprises calibrating dimensions of the image to real dimensions using the known dimensions of the calibration frames.

30. The method of claim 29, wherein the method further comprises: determining vertex by triangulation using markers at different depths on the calibration frame relative to a camera, preferably using markers located on side arms of the calibration frame.

31. The method of any of claims 27 to 30, wherein the method further comprises: calibrating the dimensions of the image with reference to a known real dimension, preferably wherein the known dimension is pupil diameter.

32. The method of any of claims 27 to 31 , wherein the method further comprises: determining a distance between lenses of the frame and each eye; and determining, using a predefined distance between the eye and ocular lens of a telescope, positioning of the telescope relative to the lens.

33. The method of claim 32, further comprising: determining a diameter of hole to be milled based on the determined positioning of the telescope relative to the lens and a known taper of the telescope.

34. A method of manufacturing loupes, comprising: measuring facial dimensions remotely; translating facial dimensions into assembly instructions; and assembling loupes.

35. A method of manufacturing a loupe, comprising: receiving at least one image of a face; determining, from the at least one image, facial dimensions; determining, from the at least one image and / or the determined facial dimensions, parameters for loupe manufacture; translating the determined facial dimension and / or the parameters into computer- implementable instructions for a machine for manufacture of the loupe.

36. The method of claim 35, wherein the method further comprises: assembling the loupe using the machine by implementing the instructions.

37. The method of claim 35 or 36, wherein the parameters for loupe manufacture comprise at least one frame parameter, preferably wherein the frame parameter comprises frame shape and / or dimensions.

38. The method of any of claims 34 to 37, wherein the translating comprises the method of any of claims 27 to 33.

39. A computer readable non-transitory storage medium comprising a program for a computer configured to cause a processor to perform and / or implement the method of any of claims 13 to 22 or 27 to 38.

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