San Jose, Calif. (AP) -- Grainy cell phone images are often used against cops accused of using excessive violence. Now, officers are being armed with their own cameras. The so-called head cameras are the latest technology to come from Taser International Inc., makers of the stun guns popular with law enforcement. "It's like the helmet cam you've seen on X Games," said San Jose police officer William Pender, who demonstrated the camera on a recent afternoon. Eighteen of San Jose's more than 1,300 sworn officers have been trained to use the AXON head cameras as part of a free trial....