A system senses audio, imagery, and/or other stimulus from a user's environment, and responds to fulfill user desires. In one particular arrangement, a discovery session is launched when the user speaks a cueing expression, which serves to switch the system from a lower activity state to a heightened alert state. The system may recognize that the speech expresses a user request that requires analysis of camera-captured imagery to fulfill. In response the system can apply an operation, such as a recognition operation (e.g., barcode decoding), to the imagery and take an action based on resulting information. Operation of the system can be aided by collateral information, such as context. A great number of other features and arrangements are also detailed.