Video Script: Poor Mans Tennis Ball Photosphere Helper

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Title: ....... Poor Man's Tennis Ball Photosphere Helper
Length: ..... 9 min 10 secs
Credits: .... Andrew Noske
URL: ........ https://www.youtube.com/watch?v=gFaG-L4gGZ8

This narrated video shows how to build a very cheap device which can help you take better photosphere (360 degree panorama) images.


Executive Summary

To read more about this device visit Photosphere helper. For me this was a fun little project what was quick and easy to build, but sadly I got busy somewhere along the way and although I collected the footage quickly it took forever to find time to edit the video.


Video Script: Poor Man's Tennis Ball Photosphere Helper

Hi, I'm Andrew and going to be showing you how to make one of these.

I call it the "poor man's tennis ball photosphere helper". Part of its function is a sun shield, but it main purpose is to keep your phone camera centered about a single point as you take photos, as this can drastically improve the stitching of your panoramas.


Without a device to keep the lense centered, capturing an indoor panorama is almost impossible, but here you see I've actually captured the inside of my living room quite nicely.


What you'll need:

  • An tennis ball, preferably one without much fur.
  • Some string.
  • A milk bottle cap.
  • A bread knife, nail scissors, box cutters, permanent marker.
  • ... and finally some type of tray so the fur doesn't go everywhere.

First step is to create a hole for the camera to look out of. Take the tennis ball and twist it like this to make a circle.

Cut this carefully with your bread-knife, trying to keep the end bit intact.

Now we need a hole to wedge in our camera into. Put one dot in roughly in the middle and measure the width of the camera for a second dot. Use the same process to draw two more lines around the ball.

For this galaxy nexus the camera is centered and as a quick measurement we need to come down to about here. Now if the camera on this phone was on this camera, we'd need to make the slit asymmetrical.

Cut out carefully with the bread-knife, not all the way of course. And cut the little connecting bits with the stanley knife.


We can now slip our phone in... and what we want is the lens to be centered, so what you may need to do is cut just a little bit more off down the bottom.

Next, we turn the camera on, and hopefully we can see out. Here I take a test shot and see a bit of the dark tennis ball on one edge, so I'll trim the hole a little bit bigger, to make sure we don't ruin our shots.


The next part will be attaching our string. First I'm going to drill a small hole into the back of the tennis ball. I've actually tried a real drill for this, but what was much easier is actually to use your nails scissors like this. Drill another hole in the middle of this little end piece. And then a big hole in the bottom of our lid, you'll see what this hole is for later. And a small one on the side.

Now cut off a piece of string 8 feet in length. What might work even better than string is fishing line, I've used string in this video so it's easier for you to see.

To thread the string, a piece of scotch tape can help. Create a little scotch tape needle like so.

Now we thead the string through the end piece once... and then twice, this makes it adjustable. Thread other end through the back of the tennis ball itself and tie a knot on the other side. And then, we're going to thread the other end through the little hole in the side of milk bottle lid and tie that in place too.


And you're finished! All we need to do now is slide the end piece to a good height and we're ready to use it.


To use this decide. stand upright with the bottom pieces hanging down. The tennis ball should be about about chin height. The lid should stay at a fixed place on the ground, and the end piece should be dangling a couple of inches above it.

We want to reduce parallax error by keeping out camera lens at exactly the same position in space for all shots - hopefully with less than a couple of inches variation. Make sure that the tennis ball piece is always dangling directly over the lid as you take each picture using Google's photosphere application. Notice my lens is barely moving. Your lid should never move.

Starting with the horizontal shots, then go up, and then down. The vertically down shot we want to do very last, and for this it's a good idea to get your camera in place first, pull your feet away.... and pull the string away just before you take the shot.

Hit the stop button on the Photosphere app, now lets see what it looks like. Processing might take a few minutes, so I skipped the wait. When it's finished, click the photosphere icon and what you can see is that it's stitched really quite nicely.


Just for comparison, let's try without our tennis ball. Even holding the camera close to my face, I still end up moving it around. It might not seem to matter, but as I show in this inset, just moving the lens a few inches we may either see the dartboard or don't see the dartboard, and various bits of the background, same as if we move up or down.

So how might that kind of parallax effect the stitching of our final photosphere. Well you might get lucky, but often you'll end up with something like this, the TV is fairly far back, so it survived, but our fan did not.


If you're really want to eliminate parallax, you'll want a tripod and almost all tripods have this standard size screw on the top.

Remember our bottle cap? Well we drilled the hole the right size that it will actually screw into place. The great thing about this bottle cap and ball method is that as we rotate the ball around, the lens will always stay perfectly fixed. Here I demonstrate how you can rotate the camera, just be wary of the fact that some of your down shots, might catch the edge of the bottle cap, which is why we cut out the semi-circle.


Here I demonstrate how to use a tripod and tennis ball to take another full photosphere. Insert your phone upside down as normal. Now face the camera away from the handle, and turn the handle. The rotate the ball itself to get the other rows. Don't forget to hold the camera in place so it doesn't fall!

For the last row of downward shots, I avoid the bottle cap issue by tilting the tripod. I'm all over the place for these last few shots, but luckily the downwards shot are the least important, and I'm not worried about my carpet.

And here's the final photosphere. This one stitched particular well, it's hard to see any seams here. The fan turned out fine. One part that didn't come out is my blinds... but actually these came out bad in most - anytime you have a repeated structure like this it confuses the stitching, regardless of how much parallex you have.


Almost the end of the video. One important thing about your tennis ball photosphere helper is knowing how to wrap it up. Just wrap the string around the end piece like so, and put it inside. What's good about thing is that it's a good size to throw it inside your hiking bag.

Even if you're bag shakes, it's unlikely to unravel, until you want it to, and then just let the bottom pieces fall to the floor.


A quick note on tripods. You'll want one that expands to chin height - so for me I like a 72" tripod. This one was only $25 on amazon, the small one even cheaper, but for I feel it's a bit big to carry a tripod hiking, so I just carry the tennis ball and string as something I can easily whip out whenever I want.

Feel free to read more about the photosphere software and tripods on my webpage. Thanks for watching!



EXTRA TEXT (NOT USED):

If you are going to go the tripod route you might honestly outgrow the tennis ball pretty fast, so it's probably worth your time buying an expensive rotating mount that screws onto the tripod, holds your camera in place, and can rotate about the lens... as opposed to rotating around the bottom here, which causes some parallax. Once you get to that level however, you'll probably also want to buy an expensive fish eye camera and software that lets you create higher quality photospheres.

When you're done with your tennis ball photosphere assistant, wrap the string around the end piece like this... and then stuff it inside in such a way that it won't come loose if you shake it. To take it out again, it should just unravel.


For me, I like this tennis ball, because it's light and fits easily into my backpack when I go hiking. Tripod's don't have to be expensive, but they are pretty heavy and bulky to carry around - even a compact tripod like this one is a little big for a hiking bag.


So that's my video, I thank you for watching. You can get more tips, advice and links on my webpage: andrewnoske.com/wiki/Photosphere_help




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