| Popis: |
In this work, we have achieved for the first time an effective speckle noise reduction simply by means of just high frequency LD driving current superposition for an ultla compact micro-electro-mechanical-systems (MEMS) based high resolution scanning beam RGB-laser projectors including the direct green emission LD. In the experiments, we have carried out quantitative evaluations of the speckle noise by overlaying the projected images using a CCD camera with histogram based estimation of speckle noise intensities. Moreover, we have examined the reduction of granular images seen by humane eyes in higher ratios in color stereo image pairs using double-stimulus continuous-quality scale (DSCQS) method. As a consequence, the noise reduction rate of 53.5% for the red laser diode, 80.1% for the green laser diode, and 50.3% for the blue laser diode was attained with histogram based estimation, and the image quality was also enhanced by speckle noise reduction with all RGB LD's using DSCQS method. Moreover, we have also investigated the noise reduction mechanisms in these RGB LD's in relation with the relaxation oscillation frequencies from viewpoint of chaotic multi-mode oscillations with existence of optical feedback. |
