Folding Paper Boxes For Facial Mask Design of three-dimensional printing

Folding Paper Boxes For Facial Mask Design of three-dimensional printing

 

1. The relationship between grid distance (p), thickness (d) and observation distance (D)

Due to the influence of human eye resolution, we can distinguish more details of near objects, and the ability to detect details of distant objects will decline a lot. For the raster on the stereo image, if we can clearly distinguish the raster column mirror, it will interfere with our visual experience and affect the performance of the stereo image. When the thickness is constant, the decrease of grid distance will increase the observation distance. Therefore, we can not only change the grid distance, but also consider the thickness factor. When the grating plate thickness is reduced under a specific grid distance, the observation distance will be smaller. Therefore, the grating plate for close observation should be thin and dense. For the raster plate used for remote observation, some details of the drawing image are lost when the grid distance is too small, but the observation effect will be affected. Similarly, in order to meet the requirements of wide grid spacing, the thickness of the grating plate must be increased. Therefore, the grating plate used for remote observation should be thick and sparse.

 

To sum up, in the manufacture of grating plates, it is necessary to first determine the appropriate grating distance according to the required observation distance, and then determine the thickness of the grating according to the observation distance and grating distance.

 

2. Parameter analysis

The above is analyzed from the relationship between parameters, and the following is analyzed from the impact of parameter selection on the image effect.

 

① Number of grating lines (LR)
The number of grating lines is the number of grating bars per inch unit and is the reciprocal of the grating distance p. The number of lines in the grating is expressed as LPI, which is the number of cylindrical mirrors in 1 inch. Generally there are grating suitable for printing 75LPI, 100LPI, 120LPI, 150LPI and so on.

 

The number of raster lines determines the accuracy of the stereo image and limits the resolution of the raster image. The higher the line number of the raster, the higher the resolution of the raster image is required, and the accuracy of the three-dimensional image produced will be higher. If the number of lines of the grating is lower, the resolution of the grating image is not too high, and the accuracy of the final three-dimensional image is relatively low. The higher the resolution of the raster image, the higher the requirements for its output equipment, and the natural output cost is higher. Therefore, when choosing the number of grating plate lines, it should be based on the actual situation, and the production cost should be kept in a reasonable range while meeting the accuracy requirements.

 

The human eye's resolution of details is limited by the observation distance, so in actual production, the number of lines of the grating should be selected according to the observation distance. The grating plate with high line number should be selected for close observation, and the grating plate with thick line number should be selected for distant observation.

 

Usually, when the observation distance is less than 80cm, the grating plate of 75LPI~90LPI should be selected, and the grating plate is thinner at this time. When the observation distance is less than 50cm, 75LPI~150LPI should be selected. In addition, the choice of the line number of the grating is also affected by the size of the image. When the image format is less than A5, the grating plate above 75LPI is applied, and the three-dimensional picture picture produced at this time is delicate and soft.

 

② Viewing Angle range (φ)
Angle of view refers to the maximum Angle that can be allowed when forming an image or viewing an image. The smaller the Angle of view, the sharper the changes in the image. Therefore, the raster plate with a small Angle of view can perform the three-dimensional effect very well and very fine, and the raster plate with a large Angle of view is mainly used to perform animation, transformation and other effects.

 

③ Transmittance (τ)
The transmittance is used to describe the transparency of the grating, which is determined by the grating material and processing technology. The higher the transmittance, the better its transparency. Since the stereogram we discussed is reproduced through the refraction of the grating plate, the transparency of the grating plate will directly affect the performance of the stereo image. If the transmittance is high, the loss of the image information is less after the refraction of the grating plate, and the brightness of the reconstructed image will be stronger. On the contrary, if the transmittance is too low, the image information will have more loss after being refracted by the grating plate, which will affect the quality and brightness of the reproduced image. Therefore, try to choose materials with high transmittance to make grating plates.

 

④ Refractive index (n)
The refractive index is determined by the grating material itself. Under certain other conditions, the grating plate with a high refractive index has a larger Angle of view θ1, and the image separation is good.

 

3. Production method of raster image

In general, there are three ways to make raster images: stereo photography, computer generation, image processing software processing.

 

① stereophotography
Stereophotography is a traditional raster image production method, the key to operation is to take stereoscopic photos, and the layout, distance, Angle, center point and so on need to be accurately calculated before shooting. It is divided into direct method and indirect method. The direct method is to place the cylindrical lens grating plate in front of the photoreceptor, move the camera in a certain field of view, and shoot the subject continuously; The indirect rule is to take more than two pictures of a particular location and then combine them accurately into one. When the raster image is made by stereophotography, the details of the image are accurately projected to the surface of the photosensitive material through the raster, and the pitch of the raster fringe matches the width of the image details, so it is very accurate. The resulting stereoscopic image has good stereoscopic effect. However, because the stereoscopic method requires special equipment, and the operation is more troublesome, the scope of use of this method has certain limitations, so there are few uses of this method.

 

② Computer generation method
This method is based on the production principle of raster image, using the computer to use the corresponding algorithm, each frame in the image sequence is cut into vertical strip image and then synthesized alternately in order, and then compressed to generate the final raster image. This method does not require special shooting equipment, and the operation is simple. Raster images can be synthesized by using image software such as Photoshop after some processing of ordinary images. Therefore, it has been widely used.

 

③ Image processing software processing method
This method uses image processing software such as Photoshop to manually segment each frame in the image sequence. Then collage the required raster image. Although the principle of using this method is simple, it is more troublesome to operate and requires certain skills. And the use of Photoshop image processing software for image synthesis, the resulting image details of the dislocation arrangement is not the actual requirements of the dislocation arrangement, so often the synthetic image will appear very obvious sawtooth phenomenon, under the amplification of the grating will seriously affect the quality of stereo image.

 

Through the analysis and comparison of the above three raster image generation methods, we believe that computer generation is indeed a more feasible method, so our company developed its own three-dimensional design software on the basis of combining the advantages of similar software in the market.