## Introduction: Sphox: the Google Sphere Box

Which camera app are you using? Is it Google camera? well, I am! The app features a handful of panorama options and PHOTOSPHERE! This is relatively new, and there aren't many instructables about it!

Photosphere a type of composited photos that grant you 360 view on google map street view! its also important for computer graphics (any robot character vfx) and scene reconstruction (the Manhattan in Avengers).

If you not into those, take it as a new kind of selfies! To record the places you are at all round!
This instructable is a quick guide of taking quick photoshpere of certain quality, optimized with a custom camera rig.

## Step 1: Sphere Vs. Box (and Some Theories)

The duals are different in many ways, or is it? to skip you a math class of Geometry, topology, dimension, space transformation, it all boils down to one question. How can a sphere like earth but map to a rectangle map?

Distortion! It is the key/consequence.
You take around 40 pictures of your environment, and google camera distort them for you! Rotate yourself around your phone camera!! You cause errors as the your phone rotate according to you!! You can yield better picture with large outdoor scene, since larger the scene, the less significant is your error. Also, with slower and more accurate rotation, your gyroscope with have a easier time calibrating.

There is an undo option, but that is mainly useful when a person walked by suddenly and block the view. If you have calibration problem/ image misplaced, you are better off restarting the whole thing.

Rotating around the camera as oppose to user Point of view (POV), can minimize the effect as explianed by a 2 min illustration above. I can totally take a very decent photosphere, slowly walking in circle around the phone, bent over and back gracefully like a Contemporary dance routine, constantly focusing on the position of the phone like a mime artist. With practice,I bet you can too! This however draws weird attention and tiring.

My purpose is to speed up the process while retaining certain degree of quality. Also investigate the option for indoor application. This is also a quick test-of-concept mid-night-built prototype after quick sketches. If it works, i am interested in 3D printing the parts for more stability and durability. Tell me what you think!!

## Step 2: Material and Tools

I did most of my work mid night, so, recycled material and all hand tools. hehe :-D

Material:

• Sketch paper
• Transparent plastic film (like those used in old school presentations)
• Thick plastic card (mine is around .75mm thick, like those in thick folder)
• Thin plastic board (mine is 2mm thick)
• Lollipop's Sticks
• light duty Velcro Strap (optional)
• old magazine

Tools:

• Hot glue
• Scissors
• Sharpies
• hammer of some sort
• cutting mat
• tripod
• sanding paper optional)

I checked the film i use is heat proof acrylic, at least against hot glue. Check your supply first to avoid shrank plastic wrinkling, and worse toxic gas. The acrylics of different thickness will be refer as Film, card and board for convenience.

## Step 3: Tailoring the Box to Your Phone

The key design is to have a box rotating about the horizon at the same level as the camera. This box with a hole for camera, will then be mounted on a frame that rotates vertically perpendicular to the horizon, about the position of the camera. the box will be build from bottom up by walls.

Here are the general steps:

1. Sketch outline of your phone on a paper, (Graph paper for accurate dimension)
2. Add approximately 5 mm and 1 cm rims on the short and long side of the outline as rim.
3. Put your paper under the plastic (acrylic), and trace the required patterns with sharpies.
• 1 x board base wall with camera hole for stiff shell
• 2 x card rims for surfacing the box and the lid.
• a few long strips from board of 1cm and 2 cm for hardening the rim.
• a few long strips from card for bending around the box as vertical walls.
• 1 x film of the size
4. Use coin and corner of cutting mat as "ruler" for curves
5. Cut the shapes out with scissors
6. Thick board are not cutter-friendly, nor sew-friendly by all means (see my blade broke in the pic?)
7. Use the screw driver as sharp edge, and hammer holes one after the other along the circumference. (Like Greek sculptors!)
8. Hot glue the inner vertical walls, make sure your phone fits in there.
9. Roll up paper cylinders and glue them on the short sides, on an imaginary line leveled with the camera. They will act as pins that rotate the box.
10. Glue a outer wall sealing the lower box.
11. Glue the board rim to the card rim for the lid.
12. Cut the velcro, long enough to wrap the around the box with lid, to desired thickness (around 5 mm)
13. Glue one end of the velcro on the lid, make sure it doesn't obstruct the camera view.
14. Roll thin papers around the pins for protection.

## Step 4: Rotating Frame

Popsicle sticks are fast wood choice for making beams and frame, even with stand some force (even of the dark side).

1. Break a few sticks in half and stack them up for convenience.
2. Find the number of stick which give thickness that your pin can fit in and rotate freely.
3. Cut the layers of sticks in alternating length (few mm difference, forming inther lock in next step)
4. Glue the left hand side of the frame alternatively by interlocking with the horizontal beams
5. Repeat the above for the right hand side except with a longer horizontal beam.
6. Roll a thick paper stick that joins both sides of the frame.
7. Roll a separate paper pipe on top of the stick, this will hold the stick for it to rotate.

## Step 5: Rig to Tripod

I used an cheap old tripod. Removing the camera mount allow me to rubber band the whole thing. Then i used some rope to secure the rig after leveling.

Get out there and take your Photosphere!! Do respect the photography rules in malls and public venues. If someone ask you "What are you doing?", "Did you apply for a photo permit?", be honest!! If they insist you to leave, Comply!! Never mess with people, especially when they think they are right!! Pick less busy hours if you have to.

Respect each other!

I didn't built the Sphox to last, you can see the frame is not leveled anymore after the day of photoshoot. I yield some interesting results, which will be discussed in a bit. I would like to point out the Shooting itself was really quick since it was my goal (around a minute and a half). But the app took time/battery processing the pictures. I tried taking new photoshpere while the app is processing the previous pic. DONOT DO IT! The app will do calculations on both pics, the final pic will be filled with artifacts easily! Or worse, Deleted!

## Step 6: Results

I chose 4 locations with different object distance/range, since it is an important factor that determines how significant the error will be. The following compares photosphere generated with my Google Sphere box and from free hand operations with in similar duration of time(which was fast). I also chose these location for its bricks and tiles, as you can tell if things really matchup.

Outdoor(large square near Science museum HK):

Mixed Space:

Outdoor (small park):

Indoor:

As you may agree, the results are inline with our theoretical prediction, the low number of visual artifact/errors is similar between 2 methods are similar in large outdoor scene. As the object distance/range decrease, the number of error increase in both methods. However, the photosphere made free hand in small park and mixed space, has noticeable traffic cones/trees and column mismatch at 5 m range. For indoor shot, the ceiling and floor is heavily misplaced in the free hand picture. While photosphere taken with our custom rig perform far better in small range. They are not perfect, due to the short shooting time i spent. I took time constraint very seriously, since this test is about quality with efficiency!

I hope you guys can view the pics on google + as it allows the sphere view, even better on android phone. you can rotating the phone around to interact with the photosphere as if you have opened a window to the space i was shooting!!

I would say this test of concept is a success, would you? tell me what you think!! and share a pic if you made one!! Also let me know in the comment session if you guys wanna apply this prototype to 3D printed parts? Thanks so much for reading my instructable!! if you like my work, please gimme a fav and a vote!!

Until next time, Happy instructabling!!

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