In the field of printing, three-dimensional printing - stereoscopic printing - stereoscopic printing has become an important content in the special printing industry. The principle of stereography is to simulate the distance between two eyes, to shoot from different angles, to record the left and right pixels on the photosensitive material. When watching, the left eye can see the left pixel and the right eye see the right pixels. The printed product based on this principle is called stereoscopic printing.
Body printing has the following characteristics:
(1) the object can be reproduced vividly, and it has a strong sense of stereoscopic. Product images are clear and rich, vivid and profound artistic conception; (2) the original three-dimensional printing is often design or scene filming, and print generally choose quality of coated paper and high temperature resistant printing ink, so good gloss, bright color, not easy to fade;
(3) the surface of the printed product is covered with a concave convex column mirror gratings, which can directly watch the stereoscopic effect of the panoramic picture. From people's stereoscopic vision of objects, the stereoscopic vision of objects mainly comes from human's physiological factors, experience and psychological factors. <br: actually, stereo vision is in the process of the visual appeal of these complex factors and the formation of three-dimensional information together. From the physiological factors, there is disparity (monocular binocular parallax and motion parallax), convergence and adjustment.
Specifically, parallax is the fundamental factor for people to obtain stereo vision, is in daily life, people see objects because of interocular differences, perspective and other reasons, the image of the object will be around the eyes see the appearance of parallax, it gives people a sense of stereo.
The effect of the stereoscopic image must be reflected by the display technology. The stereoscopic display described here refers to the reproduction of three-dimensional information of the image, which is another basic condition for obtaining stereoscopic vision. There are two main methods to realize stereoscopic display, namely, two direction display method and multi direction display method.
(1) the two direction display method. Can be divided into stereoscopic method, color filter method, polarizing filter method and alternate segmentation method. No matter which method is taken, the stereovision is obtained by observing the images by the left and right eyes of two eyes.
Stereoscopy: the basic principle of stereoscopy is to use stereoscopy to observe the stereoscopic sense of the left and right graphics. This method has been widely used since its emergence in nineteenth Century, but special stereoscopic lenses must be used, otherwise there is no stereoscopic vision. Double color filter method: the left and right images are printed in the same plane with red and blue ink, respectively, and the method of observing the printed images by red and blue filters. Because of color and ink complementary color, so the image is not observed by color red and blue instead of black. Therefore, this method is limited to black and white photographs and is not suitable for color printing. Adding different wavelengths of light into the eyes, it is easy to make eye fatigue. Therefore, this method is rarely used in addition to the use of Aeronautical maps. polarizing filter method: the left and right image respectively through the polarizing filter mutually orthogonal projection on the same plane, the left and right eyes were also observed by polarizing filters of the same.
Although this method requires special glasses, it has been widely used in stereoscopic films and stereoscopic TV. Alternate segmentation: the left and right images are presented on the same plane alternately and the unnecessary parts of the same period are shaded to create a three-dimensional sense. This method has not been popularized so far because the effect of the residual image will cause the flash and the price of the glasses is high.
(2) multidirectional display method. There are mainly parallax shielding methods and cylindrical lens method. Parallax masking method: parallax shielding method, also called parallax slit method, was invented by F.E.Lves in 1930. Its working principle is to segment the left eye image and right eye image by slit and expose it on the film, then develop, print and print. If it is placed in the same position at the time of photography, the two eyes are placed in the position of the image, and the stereoscopic image can be seen. Using the parallax slit method, if two images are synthesized, the parallax stereoscopic image can be obtained. If the opening ratio of the slit is reduced, a number of images can be synthesized and a parallax panoramic image can be obtained.