A method for simple and reliable displacement measurement with nanoscale resolution is proposed. The measurement is realized by combining a common optical microscopy imaging of a specially coded nonperiodic microstructure, namely two-dimensional zero-reference mark (2-D ZRM), and subsequent correlation analysis of the obtained image sequence. The autocorrelation peak contrast of the ZRM code is maximized with well-developed artificial intelligence algorithms, which enables robust and accurate displacement determination. To improve the resolution, subpixel image correlation analysis is employed. Finally, we experimentally demonstrate the quasi-static and dynamic displacement characterization ability of a micro 2-D ZRM.
A large size RGB LED backlight unit and its local dimming algorithm are presented in this paper. The LED backlight
unit and the LCD panel are controlled synchronously to enhance image contrast and improve power efficacy. Based on
the image content, the backlight intensity is locally dimmed, and pixel values are compensated according to the backlight
brightness distribution. In addition, a linear function algorithm typical for a backlight system is applied to remove the
grid artifacts between LED blocks. Our newly developed 32" RGB LED backlight LCD-TV prototype shows that a static
display contrast of over 20000:1 can be achieved. Compared with CCFL backlight LCD-TV, an average of about 30% of
the power can be saved depending on the image content.
The paper presents a novel optical approach to realize tracking on glass based on speckle effect produced by
vertical-cavity surface-emitting laser (VCSEL). The range of incident angle has been investigated which shows incident
angle in the range of 75 to 90 degrees is favorable to acquire a pure speckle field with purity better than 90%. In the
system, nearly grazing angle of incidence 85 degrees is introduced, and big operating current of VCSEL and high gain of
CCD are adopted to ensure signal detected. We analyze the cause of background contained in the image and remove
them by placing a barrier between the laser diode and charge coupled device (CCD) and an infrared filter in front of
CCD. After above-mentioned improvement of the system, a good linear dependence between displacement of speckle
images and amount of glass translation is proved by experiment and the slope of the fitted line agrees well with
theoretical predictions, the accuracy of tracking system is better than 4%.