Above is a basic setup I have been working on for about a month now. Self funding only allows for so much speed of development, but gotta start somewhere right?
Pictured above is an Optoma PK201 pico projector: perks include portability, universal acceptance of inputs and size, downsides are that it can only run off battery power, no direct power capability. Max life of operation per charge is about 2 hours.
For this demo I am choosing to use DVI in order to have the option of displaying HDTV resolutions (if desired) but will most likely settle for a native resolution on the projector itself.
In order for this to work, I have to use a mini - HDMI to female HDMI adapter connected to a Male HDMI to female DVI adapter which runs a DVI-D cable to my Mac Pro control computer.
If you are not familiar with the different types of DVI, this is a very informative article and will save you money and hassle when purchasing DVI cables. (trust me.)Since I'm on a mac, I'm sticking with DVI-D cables where possible.
This Nintendo DS is my object of choice for my first projection mapping project, i'll get to why in a second, aside from the fact that it's one of the few fun/gadgety white things in my room right now. Choosing an all white object allows me to use a projector to change it to any color I want with minimal color balancing (if any) and allows me to focus instead on creating cool effects for it :)
On a tripod (please forgive the picture orientation,) I am mounting the projector to aim straight down at the DS so that there is minimal to no keystoning. As soon as you have to keystone your projector, you create a warped perspective distortion that you either then have to deal with or compensate for in addition to losing any "True HD" if your project is of a larger scale.
Now I measure the length and width of the object I am projecting on. Direct measurements of physical dimensions are a MUST. (I've tried measurements from a fixed point of perspective before and only succeeded in creating a cool warp effect akin to the one in star trek.) This DS measures 13.3 x 7.3 cm. If you divide the length by the width you can get a number that represents the aspect ratio. This is an important number. For this DS we get 1.82. (*note, this is not a ratio, it is merely the number given by dividing the length by width. You can do the same with any aspect ratio for comparison, such as 16:9 [traditional widescreen] is 16 / 9 which equals 1.78.)
Now we get to look at resolutions for the projector:
Dividing the length by width we find that 1024 x 576 in fact gives us an almost perfect match for aspect ratio. Since the native resolution of this projector is 800x600 (which equals a 1.33) we will have a little "glow" or "bleed" from unused canvas on the projector, but the image set to the maximum resolution will be easier to overlay on the device itself.
With a tripod that lets you set very specific heights (most should) you have a very close match for aspect ratio which will allow for the highest resolution and clarity on your projected surface. Since we're not doing any 3D application at the moment, 60hz is perfectly fine for refresh rate and I'll do any color adjustments I need in my projection host program.
*******Since this is a simple projection mapping setup I won't bother with creating a mask for the image, but if you wanted to isolate specific portions of the DS (such as the apple sticker or the led battery lights) you would take a picture with a similar lens (ie. cameraphone in our pico projector's instance) in the EXACT location of the projector's lens and then import that photo into your masking software to generate a mask for use in video content creation at the specified resolution. More on that process here.*******
Now you can take your setup and through any number of creative softwares, develop images or video of any kind to project onto the object itself! Personally I'll be using Isadora and the 3D Quad Distort actor to fine tune my surface some, but as long as you stick to the resolution you chose in the first place, you can put anything you want to on your new surface :)
Now turn off the lights and have some fun! Y'know... in the kindof way you could tell your friends about afterwards.
An excellent website to see what other people are up to with this technology.
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