The principle and characteristics of three-dimensional printing

The principle of three-dimensional printing is to simulate the distance between two eyes of a person and shoot from different angles. The left and right pixels are recorded on the photosensitive material. When viewed, the left eye sees the left pixel and the right eye sees the right pixel. The printed matter produced according to this principle is called For three-dimensional printing.

Three-dimensional printing has the following characteristics:

(1) Can reproduce objects realistically, with a strong sense of three-dimensional. Product images are clear, rich levels, vivid image, profound artistic conception;

(2) The three-dimensional printing manuscript is often made of a design or scene shooting, and the printed matter is generally selected for high-quality coated paper and high-temperature ink printing, so the gloss is good, the color is bright, and it is not easy to fade;

(3) The surface of the printed product is covered with a concave and convex lenticular lens grating plate, and the three-dimensional effect of the panoramic picture can be directly viewed.

From the perspective of people's stereoscopic vision of objects, the stereoscopic vision produced by objects is mainly based on human physiological factors, experience, and psychological factors. In fact, stereo vision is the stereoscopic information formed by the integration of the complex factors of appeal in the visual process. In terms of physiological factors, there are parallax (parallax in both eyes and parallax in monocular movement), convergence, and adjustment. Specifically, binocular parallax is a fundamental factor for people to obtain stereoscopic vision. In everyday life, when people observe objects, due to the perspective between the two eyes, the images of the objects seen by the left and right eyes will be different. Parallax, it gives people three-dimensionality.

The effect of stereoscopic images must be reflected by display technology. The stereoscopic display here refers to the reproduction of stereoscopic information in the three-dimensional space of an image, which is another basic condition for obtaining stereoscopic vision. There are two main ways to achieve stereoscopic display, namely two-way display method and multi-directional display method.

(1) Two-way display method. Can be divided into three-dimensional mirror method, two-color filter method, polarizing filter method and alternating division method. Regardless of the method used, stereopsis is obtained by using the binocular parallax and left and right eyes to observe the image separately. Stereoscopic method: The basic principle of the stereoscopic method is to use a stereoscopic mirror to observe the left and right graphics and create a three-dimensional sense. This method has been widely adopted since the advent of the 19th century, but special stereoscopes must be used, otherwise there would be no stereo vision. Two-color filter method: the left and right images are respectively printed on the same plane with red and blue inks, and the printed images are observed through red and blue filters. Since the color filter and the ink are complementary to each other, the image observed through the color filter is not red and blue but black. Therefore, this method is limited to black-and-white photographs and is not suitable for color prints. In addition, light of different wavelengths enters into both eyes, and it is easy to make eyes fatigued. Therefore, this method is rarely used except for air maps. Polarized filter method: The left and right images are respectively projected on the same plane by the polarized filters that are orthogonal to each other, and the left and right eyes are also observed by the same polarizing filter. Although this method requires special glasses, it has been widely used in stereoscopic movies and stereoscopic televisions. Alternate splitting method: The left and right images are alternately presented on the same plane and the unnecessary parts of the same period are masked to create a three-dimensional effect. Since the afterimage effect causes flashes, masking glasses are expensive, so this method has not been popular so far.

(2) Multi-directional display method. There are parallax shielding methods and cylindrical lens methods. Parallax Shielding Method: Parallax Shielding Method, also known as parallax slit method, was invented by FELves in 1930. Its working principle is to divide the left-eye image and right-eye image by slits and exposure on the film, and then develop, Shaiban and printing. If you place it in the same position at the time of photography, and both eyes are placed at the position where the image is placed, stereo images can be seen. Using the parallax slit method, parallax stereo images can be obtained by combining two images. If the aperture ratio of the slit is reduced and the synthesis of a plurality of images can be completed, a parallax panoramic image can be obtained. The parallax slit method is essentially an inescapable reduction in the amount of light.

Therefore, it is rarely used except for the cylindrical lens method. Cylindrical lens method: A cylindrical lens can be viewed as a lens plate composed of a plurality of convex lens pieces side by side, which has an imaging effect. The back of this lens coincides with the focal plane. Due to the separation of the lens, the images A, B, C, and D in each direction can be separated into a, b, c, and d and recorded on the focal plane, as long as the left and right eyes are placed on the B and C. Position, you can see stereo images.