This clinical trial is conducted within the research project 'Computerized Lung Sound Analysis'. The research goal is the development of a system enabling the automatic classification of lung sounds, which will result in a decision support system for physicians.

The objective of this trial is to create a small lung sound corpus, enabling the development of a prototype of the described system. Therefore, investigators record lung sounds with several lung sound transducers distributed on the posterior chest of human test subjects.

In this clinical trial investigators record lung sounds over the posterior chest of human test subjects. The subjects are either lung-healthy (control group) or subjects with pneumothorax condition or pulmonary fibrosis. The lung sounds are recorded in supine position on an examination table. A foam pad with several lung sound transducers is placed under the back of the subjects. During the recording the subjects wear a nose clip and hold a pneumotachograph with both hands. The subjects are instructed to breath at a certain airflow rate during inspiration, with natural breathing during expiration. For each subject investigators simultaneously record 30 seconds of the airflow signal and the lung sounds from 16 lung sound transducers.

Inclusion Criteria:

General:

• Smoker and non-smoker
• 'Lung-healthy' subjects (control group), subjects with pneumothorax or subjects with pulmonary fibrosis

Additional for 'lung-healthy' subjects:

• COPD < 3 (GOLD Criteria)

Exclusion Criteria:

General:

• Body Mass Index > 30
• Preceding thoracic surgery
• Non-cooperation of the subject
• Intubated or tracheostomized subjects

Additional for 'lung-healthy' subjects:

• Disease of the respiratory system
• Taking medication influencing the respiration