Abstract: An external calibrating device (10) for a measurement device, which may be an acoustic camera. The calibrating device (10) includes a sound source (11) and a light source (12), which are preferably pointed to the same direction. This direction can be a horizontal direction, where the sources (11, 12) locate on the same vertical side surface of the calibrating device (10). An IR LED can be used as the light source (12). The measurement device may instruct a user how to place and align the measurement device during the calibration process. Guidance is given by instructions, volume range information, and focusing lines on the screen. When the instructions are fulfilled, the user may acknowledge the finished calibration process.

Abstract: The present invention discloses an acoustic camera which comprises an array of arranged microphones. The microphone arrangement can be organized in planar or non-planar form. The device can be handheld, and it comprises a touch screen for interacting with the user. The acoustic camera measures acoustic signal intensities in the pointed direction and simultaneously takes an optical image of the measured area, and shows the acoustic signal strengths with the taken image on the screen. The device analyzes the acoustic signals and makes a classification for the sound based on the analysis. If necessary, an alarm is given by the acoustic camera. Besides the handheld manual use, the device can be fixed on a immobile structure or fixed to a movable or rotatable device or a vehicle, such as to a drone.

Abstract: The present invention discloses an acoustic camera which comprises an array of arranged microphones. The microphone arrangement can be organized in planar or non-planar form. The device can be handheld, and it comprises a touch screen for interacting with the user. The acoustic camera measures acoustic signal inten-sities in the pointed direction and simultaneously takes an optical image of the measured area, and shows the acoustic signal strengths with the taken image on the screen. The device analyzes the acoustic signals and makes a classification for the sound based on the analysis. If necessary, an alarm is given by the acoustic camera. Besides the handheld manual use, the device can be fixed on a immobile structure or fixed to a movable or rotatable device or a vehicle, such as to a drone.