Light Homogenization Method for Multi-Source Large-Scale Surface Exposure 3D Printing

An energy homogenization method for multiple-projector large-scale mask projection 3D printing comprising the steps of:

• Step 100:
• using at least two projectors as a light-source for mask projection, and locating the projectors to be adjacent to each other so that there is an overlapped area between the projection areas of the projectors, wherein the two projectors project two images with the same property but with different pure colors, a first color and a second color, and the overlapped area between the projection areas of the projectors has a third color;
• then, using a camera to capture an image of the projection areas and the overlapped area, and analyzing the image using a computer, wherein the height and width of the overlapped area are denoted as H0 and W0 respectively;
• Step 200:
• based on the information of the height H0 and the width W0 of the overlapped area, segmenting a preprocessed slice which is obtained from the captured image to create two slices which are denoted as P1 and P2 respectively;
• recording the width W1 and W2 and the H1 and H2 of the two slices P1 and P2;
• and then generating two corresponding gray leveled pictures P3 and P4 having the same property with the two slices;
• Step 300:
• measuring the output energy at the same position on a printing area with discrete gray levels;
• by analyzing the measured data, obtaining a mapping function T[r(x, y)] by using curve fitting;
• and based on the mapping function T[r(x,y)], optimizing the generated pictures P3 and P4 using gray level interpolation;
• and
• Step 400:
• fusing the pictures P3 and P4 treated above with the two slices P1 and P2 to generate a series of 3D printed slices with energy homogenization.