If I land on an obstacle, burn a collision detector charge, and then shoot through the same obstacle, does the defender get an extra green dice?

No, but you do if they shoot back, and you can trigger stuff like trick shot on your shot.

Short answer: no extra defense die, when YOU are attacking.

Full Explanation: When you use a charge for Collision Detector, you ignore that obstacle's effects for the remainder of the round. That means you won't even roll for damage (or suffer stress) from them, and they won't cause your movement actions (boosting & barrel rolling) to fail (EDIT: @GeneralZod217 pointed out that Collision Detector lets you boost/roll through obstacles, REGARDLESS of spending a charge) . It also means you can still perform attacks, even while at Range 0 of (aka overlapping) an asteroid. To address your specific question, though: Since the attacker determines the line of fire, and whether or not an attack is obstructed, the defender would not receive an extra defense die due to an obstructed attack. However, when DEFENDING, if the line of fire is drawn through that obstacle, unless the enemy attacker also had a way to ignore the obstacle (or otherwise modify the number of defense dice, like Wedge or Outrider ), you would still get to roll an extra defense die, yourself.

TL;DR: Collision Detector helps you when you're attacking, and doesn't hurt you when you're defending.

Sorry but I don't think your explanation is 100% correct.

Collision detector would still allow you to boost or barrel roll over/onto an obstacle without spending the charge. Basically a boost/ barrel roll action will not fail if it causes you to hit an obstacle.

After doing so you may then choose to spend then charge if you wish to ignore the effects of the obstacle, roll for damage, lose action/attack etc.

6 hours ago, GeneralZod217 said:

Sorry but I don't think your explanation is 100% correct.

Collision detector would still allow you to boost or barrel roll over/onto an obstacle without spending the charge. Basically a boost/ barrel roll action will not fail if it causes you to hit an obstacle.

After doing so you may then choose to spend then charge if you wish to ignore the effects of the obstacle, roll for damage, lose action/attack etc.

Good point; top post edited for clarity.