Comparison of CMOS and CCD cameras for laser profiling

The recent introduction of high dynamic range CMOS-cameras with logarithmic response to light intensity, justify a serious evaluation of the technology as an alternative technology for laser profiling. This paper presents a series of comparative tests of a high quality CCD-camera and a high-dynamic range CMOS-camera. Standard gray scale charts are used to verify the intensity response and the signal to noise ratio at different f-stops. It is shown that the high dynamic range of the CMOS-sensor makes the camera suitable for differential image laser profiling. Furthermore, the cross-section of steel rods and wires are observed to verify the industrial applicability of the different standards. Both, material at room temperature and red-hot glowing steel bars were measured. The advantages and disadvantages for each technology are shown on the basis of these tests. Finally, a laser profiler was manufactured with the CMOS-camera and successfully implemented in a steel-mill.