Horizontally scanning holography to enlarge both image size and viewing zone angle
Horizontally scanning holography to enlarge both image size and viewing zone angle
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水平扫描全息术可放大图像尺寸和可视区域角度
DOI：
10.1117/12.808831
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Y. Takaki
中科院分区：
文献类型：
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作者：
Naoya Okada;Y. Takaki
为了扩大全息图的图像尺寸和视场角，由高速空间光调制器（SLM）产生的图像通过变形成像系统转换成垂直长的图像，并且该图像通过电流扫描仪水平扫描。SLM的水平像素间距的减小提供了宽的观看区域角。图像高度的增加和水平扫描使图像尺寸增大。在本研究中，使用分辨率为1，024 ×768的数字微镜器件（DMD）作为高速SLM。使用波长为635 nm的激光二极管作为光源。畸变成像系统水平和垂直方向的放大率分别为0.183和5.0，可生成2.56 mm×52.5 mm的垂直长图像，水平像素间距减小到2.5 μm，可提供15°的水平视场角。电流扫描仪的水平扫描宽度为73.1mm，因此得到的图像尺寸为73.1mm × 52.5mm。电流扫描仪的扫描频率为60Hz，DMD的帧速率为13.333kHz，因此一个全息图由222个纵向长图像组成。垂直长图像以0.32 mm的水平间距显示，并且存在大量重叠。我们成功地生成了具有15°水平观看区域角和3.5”屏幕尺寸以及60 Hz帧速率的全息图像。
In order to enlarge the image size and viewing zone angle of a hologram, an image generated by a high-speed spatial light modulator (SLM) is converted into a vertically long image by an anamorphic imaging system, and this image is scanned horizontally by a galvano scanner. The reduction of the horizontal pixel pitch of the SLM provides a wide viewing zone angle. The increase of the image height and horizontal scan enlarge the image size. In this study, a digital micromirror device (DMD) with the resolution of 1,024×768 was used as a high-speed SLM. A laser diode with the wavelength of 635 nm was used as a light source. An anamorphic imaging system had the magnifications of 0.183 and 5.0 in the horizontal and vertical directions, respectively, to generate a vertically long image with the size of 2.56 mm×52.5 mm. The horizontal pixel pitch was reduced to 2.5 μm to provide the horizontal viewing zone angle of 15°. The horizontal scan width of the galvano scanner was 73.1 mm, so the resultant image size was 73.1 mm×52.5 mm. The scanning frequency of the galvano scanner was 60 Hz and the frame rate of the DMD was 13.333 kHz so that one hologram consisted of 222 vertically long images. The vertically long images were displayed with the horizontal pitch of 0.32 mm and there were substantial overlaps. We succeeded the generation of a hologram image having 15° horizontal viewing zone angle and 3.5" screen size with a 60 Hz frame rate.