Thanks for your reply!
So it seems that it's necessary for us to DIY the projector ourselves.
As for the necessary law of laser, I'm sure there is no problem for a 100-200mW laser device, despite the fact that we've already obtained a 400mW laser light.
The complexity of the images is simple(some edge images from the programs which use like Canny edge-detection) and project it onto the ground we walk. Projections of them on the ground may be echelons but we would fix it. The height of the projector is about 1m-1.5m and the color or the brightness is not so important for us. After all, it's the first try of it, and we may do the adjustment of them if the prototype works well.
The components may be:
1.The laser shark DAC board from Nelson.
2.a 100mw 532nm green laser module 5V with TTL.
here3.Galvos and Galvo amp: a XY galvo is enough as long as the laser's wavelength in the galvo's wavelength range ? But amplifier and the power of them we are not sure what to purchase. It may takes long to get all the components from Internet so we are cautious about which and what to buy.
Sorry for my poor descriptions and hope for some advice !