The reconstructed image from digital holography are laden with many distortions. The main cause of these distortions is known as the finite size of pixels in the display panel/chip. Due to this finite size, the starting position of the reconstructed rays in each pixel can be any place in the pixel. Hence the starting position can be different from the recording beam position which is usually considered as the center of each pixel. This difference makes that the reconstructed rays are no longer the phase conjugated rays of their corresponding recording rays. The reconstructed rays are somewhat distorted in their wavefronts. To estimate these wavefront distortions, a Shack-Hartmann wavefront sensor is used in the pathway of the reconstructed beam. The phase distribution obtained with the sensor reveal that the distortion is more for the bigger pixel size and for the images with more reconstructed image points as expected. This result indicates that the sensor is a reasonable method of estimating the distortions in the reconstructed image. The same sensor is also used to estimate the functional performance of holographic optical elements for image projection.
A design concept of a goggle type HMD (Head Mount Display) which is capable of controlling automatically user’s interocular distance is introduced. A linear motor is hired for each of the left and right pupillary distance control based on the measurement of the interocular distance with a micro-camera located at the top of the microprojector for each eye. A half mirror for each eye is used to connect the projector/camera to a corresponding eye. Each camera measures its corresponding eye’s pupil with a high accuracy under the illumination of infrared light located at near the camera. The distance range of the controlling is 55 mm to 75 mm. The maximum travelling distance of each linear motor with the four optical components is 10 mm.
An aperture sharing camera to acquire multiview images are introduced. The camera is built with a mirrorless camera and a high speed LC shutter array which is located at the entrance pupil of the camera’s objective, to divide the pupil into a number of sections with an equal dimension, The LC shutters in the array is opened one at a time in synchronizing with the camera shutter. The images from neighboring shutters reveal a constant disparity between them. The disparity between the images from the camera matches closely with that calculated from theory and is proportional to the distance of the each LC shutter from the camera’s optical axis.