Stylized 2D Fabrication of Non-photorealistic Images

A current trend in computer graphics is the use of programmable tools that allow non-experts to engage in object design. Within fabrication, one area of research focuses on non-photorealistic images which are stylized to depict a particular aesthetic quality or convey key information. In cases where authenticity is demanded or the images need to be manipulated, fabrication is necessary. Non-photorealistic image fabrication involves two challenges: identifying and abstracting key information during design and considering material restrictions during fabrication. This thesis showcases two examples for fabricating new types of non-photorealistic images, the first involving watercolors, and the second producing tactile images on microcapsule paper for improved shape understanding for the blind. The watercolor project is the first to fabricate watercolorized images and produces color-gradients using a wet-on-wet technique by limiting the usually unpredictable outcome of this medium. The tactile project implements a novel multi-projection line drawing design for the depiction of everyday 3D shapes, different from currently used designs. For the fabrication of watercolor images, we propose an image analysis pipeline which inputs an image, extracts key information elements such as color, gradients, and details, and combines them to design wood stamps produced by a laser cutter. We then paint the stamps with watercolors and press them on water-sprayed paper, following a carefully designed fabrication process. For the fabrication of the tactile images, we gather characteristics that convey shape information through touch from studies in cognitive psychology, human-computer interaction, and our own formative studies. We process a 3D pre-segmented object, compute a multi-projection line drawing of the shape's cross sections, and laser engrave the drawings as tactile images. We run user studies that show the usefulness of stylization on both image designs. These two pipelines highlight the importance of image and geometry processing and analysis, key approaches, in the two applications, one of an artistic and another of a utilitarian nature. These graphics approaches play the role of “painter” and “designer of tactile graphics” and allow non-experts accessibility to these challenging fabrication design spaces