Noise reduction is becoming increasingly important. Disturbing noises should be avoided for passengers in vehicle interiors and also for residents during pass-by or overflights. The Acoustic Camera helps the sound designer to implement the necessary measures. Not least through national and international standards and specifications, noise emissions have to be reduced, in some cases drastically. In order to know where suitable actions should be taken, it is necessary to determine as early as possible where loud sound sources occur. The Acoustic Camera localizes these sources, both in the time domain and in the frequency domain. In an train or airplane cabin, for example, a spherical microphone array is used to calculate a 3-dimensional acoustic image that impressively depicts possible weak points.
When driving by, even a long freight train is put together to form a single picture and color-coded with the acoustic data. This pass-by picture shows at a glance in which areas of the entire train the loud places can be found.
The PassBy 2D software module creates a panoramic image with the feature point method. That means: Looking for feature points in individual frames and stitching them together. From the moving distances of the feature points and the frame rate of the camera velocity information of the measured object is also created.
The calculation of an acoustic map works like a TDBF (time domain beamforming) algorithm with variable runtimes. Every point of the measured object is followed a given amount of time while it is in the proximity of the microphone array.
Travelling in a business aircraft should be as pleasant as possible for the passenger. A company responsible for the interior design of these aircraft discovered an annoying noise during a quiet flight in its new top-class business aircraft. In order to ensure a high standard of quality, the goal is to keep the noise level during the flight as low as possible. The Acoustic Camera was used to identify the main sources of noise. Acoustic insulation could then be applied during the next maintenance cycle.
Vibration and sound analysis play an essential role during aircraft development, but also for maintenance. Since vibrations have a strong influence on safety, service life and comfort and aircraft are exposed to strong stimuli during operation, knowledge of the aircraft's dynamic behavior is a prerequisite for later use. The measurement and analysis of the vibrations can be carried out both during operation and by means of static tests.
