Pupillary Distance - VisTech.Projects Android and iOS apps and custom application development

Pupil Distance Meter - PD measure

Description

Pupil Distance Meter is an iOS app that uses a camera and a known size reference object to measure pupillary distance. Pupillary Distance is needed when you want to order eyeglasses. Now you can measure it yourself using this app or ask your friend to measure your PD.

READ ME FIRST

Features:

Back and Front Camera support
Pre-defined and custom reference objects
Imperial and Metric measurement units : mm, cm inches
Accurate manual ruler adjustment
Zoom View for accurate ruler adjustment
Share results with picture attached
Countdown Timer with sound

Post about measurement accuracy.

Inch, mm, cm units are supported in the app. Zoom View feature allows you to align the pointers on the screen accurately. The option to share PD results is also available in the app. Timer feature helps the user to perform measurement on himself using front camera.

To achieve accurate and consistent results two successive pictures has to be taken and marked according to the guide. Afterwards the app estimates average pupillary distance and shows results at the top.

If you like the app and find it useful please support us with your feedback and comment. Feel free to contact us with any questions or comments.

App Screenshots

How to use

Pupil Distance Meter for iOS. How To Measure Pupillary Distance ‎‎‎‎(PD)‎‎‎‎.

https://lh4.googleusercontent.com/Kjg7WRClTZqZGyhl2D6RSCWRuaz0_hepM-iLAIzZ_x4Cl_2fFtN_JtI0D8t5QY0J7xgVsvRjM338mLkrZyuUnwvFvOlxXXHKJHQhcVyqM3vf4wTyq07ihqJlV-uWGqOVwg

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Select a reference object or define a custom one by entering length and units in the Preferences.
Switch from Front to Rear camera if needed.
Adjust camera distance so your face is in the pattern on the screen - symmetrical to the vertical line and eyes are placed in the special eye areas.
Please keep the reference (e.g. credit or id card) in the "green area" of the pattern and parallel to your device plane, do not tilt or bend it.
Look straight in the direction of the camera. To get proper PD result try to look through the device (don't focus your eyes on the device)
Press "Take Photo" Button to start a measurement session.
After the first picture is taken, please adjust the camera distance so the face fits the new (zoomed-out) pattern. Move the camera as much as possible for the second picture to be taken.
The second picture will be taken automatically after specified time. DO NOT MOVE your head and the reference object during transition between the first and second picture.
After the second picture is taken, mark the reference with blue ruler and your pupils with white one on both pictures. Switch between pictures using “1 | 2” buttons if needed.
Confirm correct ruler position using On/Off switch button when you are done with adjustment.
When adjustment confirmed on both pictures, see the PD results at the top of the screen. The normal PD range for adults is between 50mm and 78mm, 41mm to 55mm for kids.
Use “Camera” button to start a new measurement.

Touch Guide for Pupil Distance Meter for iOS

Tips

The method gives accurate results but it is very sensitive to alignment inaccuracy so please follow these tips to achieve the best result:

do not bend or tilt the card
hold the card parallel to the camera
do not move your head and the reference object during measurement session
thoroughly align the rulers, try to mark the card exactly on edges (see picture)
keep blue ruler parallel to the card sides (see picture). (!) draw the blue line over the edge of a card stripe to align the ruler properly
align the rulers roughly first and then make it accurate with the second touch
use the empty area of the screen (outside currently selected point) for fine point alignment and small adjustments

If you use a credit card as a reference and share your measurement results with a screenshot, please MAKE SURE YOUR CREDIT CARD INFORMATION IS NOT VISIBLE. You are sharing your information on your own risk, VisTech.Projects LLC is not responsible for it.

Simulation and Accuracy Tests

UPDATE 10.2015 : SEE BLOG POST ABOUT ACCURACY

Simulation has been performed to check measurement accuracy using a model where the distance is very simple to measure with the ruler as shown on the picture.

The PD distance for this model is ~26-27 mm.

PupilDistanceMeter has been used to measure the same distance and to compare results.

As described in the “How To Use” section two successive pictures are taken with different scale by moving only camera from the object to different distance. The reference length (ROL) - in this case long side of a credit card - is marked with the blue ruler. The white ruler is used to measure PD (pupillary distance). Two measurements are to be confirmed ("ON") with the switch button at the lower right corner. To switch between pictures “1 | 2” buttons are used.

When measurements on both pictures “confirmed” the PD result is shown at the top of the screen.

The final average result PD = 26.59mm.