| 摘要 |
In a method for monitoring or scanning an object, material or the like with the aid of a camera (2) movable in relation to the object or material, data recorded by the camera is stored sequentially as pixel values. A reference value is determined from one or more selected, stored pixels. The difference between the value of the actual pixel and the reference value is determined, after which changes in the object or material are detected from said difference. A system for such monitoring or scanning comprises a camera and a data-storage unit for sequential storage of recorded data as pixel values. A reference-producing unit (10) is arranged to produce a reference value from the value or values of one or more selected, stored pixels, and a comparison unit (6, 8) is arranged to form the difference between the value of the actual pixel and the reference value. |
