DE10125050A1 - Method for determining centering data for working of optical glass in spectacle frames, requires taking at least one digital recording of the customer with matched spectacle frame, for display on image screen - Google Patents

Abstract

A first raster line joins the lower or upper edges of the spectacles frame and two raster lines perpendicular to these are arranged outside and inside the edges of the disc-shape of a glass and a raster point for marking the null viewing point on the cornea reflex of the corresponding pupil, is shifted. For determining the null viewing point of this glass the spacing between the vertical raster lines is ascertained by computer and is compared with the previously inputted disc width and web/bridge width. From the conversion of the determined disc spacing of the vertical raster lines to the actual disc widths, a calibration ratio is calculated with which, by using the coordinates of the raster points, the horizontal actual position of the null viewing point of the glass, is determined.

Description

The invention relates to a method for determining centering data for incorporation optical glasses in spectacle frames, especially for progressive lenses, to ensure that the remote centering point lies exactly in the zero-gaze direction of the glasses wearer and the Pro alignment channel and the near center point aligned exactly with respect to the zero view direction are.

Such methods for determining the centering data, which are then used to Controlling the grinding in of the glasses by the spectacle lens edge grinding machine is known.

With its Video Infral system, Carl Zeiss offers a digital measuring system with Ka mera unit and software for the exact measurement of the lens centering (Www.zeiss.de). The construction of the measuring unit includes PC, monitor, printer and camera unit with two height-adjustable cameras and a deflecting mirror.

The spectacle wearer stands with the adapted spectacle frame to avoid uncontrolled Detectable convergence and parallaxes at least 4 meters away in front of the cameras.

With the height-adjustable cameras, the face of the glasses wearer is placed on the middle of the Brought monitors. The spectacle wearer fixes a directional light-emitting diode. So that's it exact zero sight direction determined. Front and side view hold the so-called "System glasses frame face" firmly.

All further steps for the precise evaluation then take place on the screen, where to count:

• - Determination of the inclination of the spectacle frame and the corneal vertex distance,
• - determination of the position of the pupil centers in relation to the frame,
• - Output of the centering data after the eye rotation point request Single vision lenses (including conversion of prismatic effects) and
• - Output of the centering data according to the field of view requirement for multi-strength lenses and progressive lenses (including conversion of prismatic effects).

The disadvantage of this system is the use of two cameras.

Another system is VISU-POiNT 2000 from ULEV GmbH (www.visu- point.com). This system, which works with the VISU-POiNT 2000 software, allows in addition to measuring the pupil distance and the height, the fade-in of the glass scraper Ions with all markings and near edges. Even the measurement of the cornea vertex distance and the calculation of the centering data based on a prismatic ver order is possible. The centering result is shown as a table and as a graphic representation of the box system as well as the viewing points on a scale of 1: 1 for a later check printed.

The main handling of the system provides after the program start:

• - Frame selection (if necessary, VISU-FrAME for support of the frame consultation) and frame adjustment,
• - Preparation of the glasses wearer for the VISU-POiNT 2000 recording Placing a cross visor on the frame and placing on Location in natural posture and head posture,
• - Align camera and take centering image ("freeze optimal live image"),
• - Print out the computational processing of the centering image and centering report.

The disadvantage of this system is the use of an additional visor cross bracket with fixed points.

The object of the invention is a method for determining centering data for the Einar processing of optical glasses in spectacle frames that can be used flexibly and with a reduced equipment expenditure allows precision measurements.

This object is achieved with the characterizing features of claim 1, advantageous adhesive configurations are the subject of the subclaims.  

The method according to the invention for determining centering data for incorporation optical glasses in spectacle frames, in particular for progressive lenses, in the case of at least a digital recording of the customer with adapted glasses and made is displayed on a screen, the image with raster lines that can be moved on the screen lines and points are overlaid and the position of the centering data is calculated The one that is used to grind the glasses into the spectacle frame provides that a first grid line connects the lower or upper edges of the spectacle frame, two to this grid line, vertical grid lines outside and inside on the edges of the disk shape a glass and a grid point to mark the zero point of view the corresponding pupil is shifted to the corneal reflex, to determine the zero point of view of this glass the distance between the vertical Grid lines determined by calculation and with the previously entered slice width and Web width is adjusted in such a way that from the conversion of the determined distance a calibration ratio is calculated from the vertical grid lines to the actual slice width with which, using the coordinates of the grid point, the horizontal actual position of the Zero viewpoint of the glass is determined and by using the 1/2 web dimension of the Distance from zero to the center of the glasses as a setting for grinding in the lens is determined, and using the calibration ratio and the computational determined vertical distance of the grid point to the horizontal grid line Actual dimension for the horizontal position of the zero viewpoint as a further setting variable for the on grinding the glass is determined.

By arranging the grid lines on the edges of the pane shape of a glass Without an additional camera or crosshair, he can determine the zero point of view reichbar. Of course, this also leads to a we compared to the prior art less expensive software, so that the process is less expensive and is therefore also feasible for smaller optician practices.

In an advantageous embodiment of the invention it is provided that the individual head inclination of the photographed customer by means of a visible and rotatable auxiliary line determined by parallel position to the upper or lower frame edge and for a precise The determination of the vertical and horizontal centering values is further used by the grid lines are adjusted to this head inclination or the head is turned until the The auxiliary line and the horizontal grid line coincide or run parallel.  

In a further embodiment, the method provides that the selection of the sliding lens type from a list is computationally compared and displayed whether the far and near centering point of the progressive lenses have an optimal position with respect to the zero viewpoint, namely
the zero point of view and the far center point of the progressive lens coincide and the near center point is just above the lower edge of the spectacle frame.

In addition, the necessary raw glass can be used in arithmetic engineering in an embodiment of the method diameter determined and then ordered.

It has proven to be advantageous for the method according to the invention if the images have at least 800 × 600 pixels and the resolution of the image points greater than or equal to 4: 3.

The method according to the invention is to be explained in a practical embodiment below:
A commercially available digital photo camera is used, which can take pictures with a resolution of 3.3 megapixels and has a 3x optical zoom and 6x digital zoom. This camera is located on a stand that can be changed in height.

The customer, who wears precisely adapted glasses, stands in a habitual head and body hold at an approximate distance of 3-5 m in front of the camera and look into the Ob lens of the camera. To realize the zero gaze direction, the photo unit is used with the Tripods at the level of the customer's eyes. The correct height centering of the camera can be checked via the rear display of the camera. To achieve more precisely and evaluable images, the camera is set to 2x zoom and the recording always done with flash. For possible sources of error when creating the image To minimize hung, it is recommended to use the recordings with the highest resolution of Save 2048 × 1536 pixels.

The recordings are then made on a 48 MB Compact Flash in the camera Memory card secured and then on a card reader on the hard drive of the Computers. There, the digitally created images can be exported using software be evaluated.  

After starting the program, an image field appears, in which an integrated "file" is used explorers "the digital photo to be measured is loaded. Then the individual The inclined head of the photographed customer using a faded-in and rotatable tool never determined by parallel to the upper or lower rim of the frame and for one precise determination of the vertical and horizontal centering values used.

Once this has been done, 2 movable vertical grid lines, a changeable scale right grid line and a movable grid point are shown. These lines will be with the previously determined angle of inclination of the head.

In the first step, the vertical grid lines are on the edges of the right panes form (nasal and temporal) pushed as tangents. This is done by clicking and Move with the mouse.

In the second step, the superimposed grid point with the corneal reflex of the pupil brought to cover (same action with the mouse). After that is done by a dashed line running perpendicular to the frame appears at this point. the This is used to move the horizontal grid line to the intersection of the dashed line and to move the lower disc shape. So the height of the point of view at this Position can be determined. However, it is possible to ignore this intersection and the horizontal grid line, similar to the vertical lines as a tangent to the lower one Lead disc shape. This procedure takes into account the so-called caste system. Which setting is used depends on which basic setting the lens grinder used.

In the third step, the size measurements of the glasses are entered as a box measurement system. the They are always given as such in the version and are indicated by the pane width and Bridge width formed. Should it be old glasses where the size is not is more recognizable, it is possible for the optician without effort, the size according to Kas measure yourself.  

If you now click on the "Calculate" button, the calibration takes place within the program. It the pixel distance between the vertical raster lines (nasal, temporal) is determined and in relation to the real pane width. Then the distance between Center point and nasal vertical grid line determined and with the calibration ver relationship mathematically linked. The value calculated in this way is ad with half the web width dated and displayed as a horizontal measure for the zero view point from the center of the glasses. The vertical distance from the grid point to the horizontal grid line is then determined sets and in turn converted with the calculated calibration value. This is how it came about The result describes the measure for the viewing height. It is advertised as such shows.

The dimensions for the zero view point of the right glass and the left glass must be separate are determined, and are therefore also a horizontal centering distance (from the horn skin reflex to the middle of the frame) and vertical centering distance (from the corneal reflex to the lower inner edge of the glasses) issued separately. These results can be delivered printed out and passed on to the workshop for incorporating the glasses.

The program also has some other useful additional functions that it z. B. enable you to determine the raw glass diameter to be ordered and the location of the Nah check reference point in the socket.

This means that the calculated horizontal and vertical centering dimensions are highly accurate have several correction data integrated into the program.

Conventional progressive lenses are used by the glass producers on a medium scale distance of 15 mm and an inclination of 10 °. They deliver when observed this parameter the best imaging properties. So it’s very important adjust the customer's glasses precisely before taking the digital photo. At nor With the painter's head posture and zero vision, the frame should be tilted forward by 10 ° point. This can be checked with an inclinometer. Since the photos from Spectacle wearers, however, takes no account of the inclination of the frame, i.e. vertically, inevitably there is a reduction in the height of the glass panes in the photo. Through the Taking into account a correction value, this error is minimized.  

Also the fact that the photo of the glasses wearer at a finite distance (approx. 3-5 m), there is an error. This error depends on the vertex the glasses stood between 0.24 mm and 0.71 mm. Corresponding correction mechanisms in within the program minimize this error to a range between 0.0 mm and 0.21 mm.

Claims (6)

1. A method for determining centering data for optical glasses, in particular for sliding glasses, in which at least one digital recording of the customer with adapted glasses is made and displayed on a screen, the image is covered with raster lines and dots that can be moved on the screen and from them Position the centering data are calculated, which are used to grind the glasses into the glasses frame, characterized in that a first grid line connects the lower or upper edges of the glasses frame, two grid lines perpendicular to this grid line are arranged outside and inside on the edges of the lens shape of a lens are and a grid point to mark the zero point of view on the corneal reflex of the corresponding pupil is shifted, to determine the zero point of view of this glass, the distance between the vertical right grid lines determined by calculation and with the previously entered slices width un d web width is adjusted in such a way that a calibration ratio is calculated from the conversion of the determined distance of the vertical grid lines to the actual pane width, with which the horizontal actual position of the zero point of view of the glass is determined using the coordinates of the grid point and by using the 1/2 The distance between the zero point of view and the center of the glasses is determined as a setting variable for grinding in the lens, and, using the calibration ratio and the computationally determined vertical distance between the grid point and the horizontal grid line, the actual dimension for the horizontal position of the zero point of view as a further setting variable for grinding in the glass is determined. 2. The method according to claim 1, characterized in that the individual head tilt of the photographed customer by means of a superimposed and rotatable auxiliary line by parallel position to the upper or lower frame edge and for a precise determination of the vertical and horizontal centering values is further used by adapting the grid lines to this head inclination o which the head is turned until the auxiliary line and the horizontal grid line together fall or run in parallel.   3. The method according to claim 1, characterized in that Computationally calibrated and displayed by selecting the progressive lens type is whether the far and near centering point of the progressive lenses with respect to zero viewpoint have an optimal location, namely the zero point of view and the remote centering point of the progressive lens coincide and the near center point is just above the lower edge of the frame. 4. The method according to claim 1, characterized in that the images have a minimum size of 800 × 600 pixels. 5. The method according to claim 1, characterized in that the resolution of the pixels is 4: 3 or greater. 6. The method according to claim 1, characterized in that when taking pictures with normal head posture and zero gaze direction, the frame one Has a forward inclination of 10 ° and the resulting shortening when shooting calculation of the glass pane height on the digital image using a correction factor is technically balanced.