Cool. But one thing I noticed is that because you write
images = CurrentImage[2]
the framerate is divided by two. A better way to do it might be
image=CurrentImage[];
oldimage=CurrentImage[];
Dynamic[oldimage=image;
image=CurrentImage[]]
Here is a rewritten faster version
With[{keySize = 40, threshold = 0.05},
With[{overlay =
Image[Table[
If[i === keySize || i < keySize && Mod[j, keySize] === 0, 1,
0], {i, 1, 240}, {j, 1, 320}]]},
DynamicModule[{image = ImageReflect[CurrentImage[], Left -> Right],
oldImage = ImageReflect[CurrentImage[], Left -> Right], imageKeys,
diff, imageKeysDiff, keysPressed},
Dynamic[
oldImage = image;
image = ImageReflect[CurrentImage[], Left -> Right];
imageKeys =
Flatten[ImagePartition[ImageTake[image, keySize], keySize]];
diff = ImageDifference[oldImage, image];
imageKeysDiff =
Flatten[ImagePartition[ImageTake[diff, keySize], keySize]];
keysPressed =
Flatten[Position[
Mean[Flatten[ImageData[#]]] > threshold & /@ imageKeysDiff,
True]];
EmitSound[Sound[SoundNote[#, .2, "Xylophone"]]] & /@ keysPressed;
Show[ImageAdd[image, overlay], ImageSize -> 1000]
]]]]
