Making google cardboard work properly (with a web browser) part 2

Now I could set (and adjust) the lens spacing in my Google Cardboard, I needed a way to set up the spacing properly, but first.....

Rule 1: your display needs to have at least an 11cm wide viewable area - preferably a bit more. Without this width, significant areas of the image will only be visible to one eye - oh and I might need to adjust the app so it allows the panel to go off the edge of the screen.

To help with setup, I prepared a freestanding web page that enables settings to be tweaked, and saves those settings to local storage so they are persistent.

This web page can also be used as the base for display of stereogram images and similar things (like live streaming from stereo webcams), and can be run on devices that don't support the google cardboard app, so you can use google cardboard (the cardboard) without google cardboard (the app) - although not with any google api based apps obviously.

Now to getting the lens spacing properly setup. For me this means that:

1. on first looking through the cardboard, the image should look right immediately - no waiting for the image to 'come together'
2. shutting you eyes for for a few seconds and opening them again should likewise mean the image 'works' immediately
3. The image should remain consistent across the whole field of view - no queasy feelings as you look towards the edges and corners of the view

web pages and other stuff.

I wanted to make the little app as widely usable as possible - not just android - and to that end it is effectively a freestanding web page - here is a typical screenshot of the app in motion:

Below is the method I use to setup cardboard. The setup also prepares the settings for use in a stereo image viewer web page I am working on - more of that another day!

Note if you have a lazy eye or suffer from bouts of double vision or similar eye problems, you probably shouldn't do it this way!

Making google cardboard work properly (with a web browser) part 1

First experiences with Google Cardboard were that things looked 3D, but it always felt a bit weird and uncomfortable. Usually the 'not rightness' got worse as I looked further from the centre of the image. To start with, I messed around with profile generator, but soon came to the conclusion I was starting from the wrong place.
Could I make it better?

Having worked out what I thought was the problem, the answer is yes, it can be made LOTS better (well it is for me anyway)

I decided that there are 2 main problems:

1. because the lens spacing doesn't match my ipd, and the lenses have a fair bit of distortion, there is a small sweet spot and as I looked away from the sweet spot, the 2 views diverge in ways my brain did not like. This makes things feel more and more 'not right' as you move further from the centre.
2. The lenses introduce a lot of pincushion distortion - I suspected that while not ideal, things would look a whole lot better if the spacing is fixed even with this distortion.

Of course having fixed item 1, a new profile should make the google app (and others that use the underlying cardboard API) look a whole lot better as well - after generating a new profile.

Google cardboard is set up for an ipd of around 64mm, and I measure my eyes at 67mm, but even this small difference seems to have a big effect.

So I set off a couple of days ago to:

1. fix the ipd to lens mismatch.
2. write an app (web page) that would allow me to view stereo pictures in a web browser.

and so our quest begins.... Part 1 is below, part 2 is here