I find the functioning of a [laser rangefinder](http://en.wikipedia.org/wiki/Laser_rangefinder) confusing.

The explanation usually goes like this: "you shine a laser beam onto the object, the laser beam gets reflected and gets back to the device and time required for that is used to calculate the distance".

Okay. But the object surface can be uneven and not perpendicular to the laser beam so only a tiny fraction of beam energy is reflected back to the device. And there's plenty of other radiation around, sunlight included.

How does a rangefinder manage to "see" that very weak reflected signal in a reliable manner?