intent to phone software earlier work by the assignee in gesture interfaces is shown in u s pat no 7 174 031 in the exemplary embodiment a tip down gesture is used to signal that the user wants to pursue a link associated with the hand cursor when this gesture is sensed the phone presents a screen of detailed information about the selected advertisement u2014 commonly with a richer presentation of information than is available from the print ad alone e g including photos links to videos etc the foregoing discussion described a simple interaction from the user 39 s viewpoint the following discussion provides underlying technical details of this exemplary embodiment when the watermark reader is activated the software monitors data output from the phone 39 s camera system the software wants to read a watermark u2014 any watermark u2014 to learn something about the user 39 s activity in an illustrative embodiment the watermark detector does not try to read a watermark unless imagery of a suitable quality is available if suitable imagery is available it is buffered and analyzed to determine whether a watermark appears present if so a watermark reading operation is performed various assessments can be performed in this regard one is to consider the phone 39 s motion if the phone is moving actively the imagery is probably too blurry to be useful for watermark reading phone motion can be judged from sensor data e g accelerometer gyroscope if the indicated motion exceeds a threshold the captured imagery may be disregarded as of little use in contrast if the motion is below a threshold the user is holding the phone steady enough that imagery suitable for watermark decoding may be captured instead of inferring image blurriness sharpness from other.