A dot profile model to compensate dot shape irregularity errors of inkjet printers is proposed. Previous tabular approaches for parameterizing the printer model rely on the measurements of the gray level of various printed halftone patterns. However, lots of patterns need to be printed and scanned if the printer generates large drops of colorant. To solve this problem, we propose to simulate the appearance of the rendered patterns so that the model parameters can be computed analytically. The simulation uses the mean dot as the printer dot profile and saturated addition to resolve dot overlap. Besides, we incorporate a standard definition (SD) and a high definition (HD) equivalent gray-scale representation of the printed halftone image produced by the dot profile model into the direct binary search (DBS) algorithm. Experimental results show great improvement in the mid-tone and shadow regions over the printed image halftoned by the original DBS. The HD model further enhances details in the shadows.
Gamut mapping algorithms (GMAs) map all the colors within the input image to colors reproducible with a printer. In this paper we discuss a gamut mapping algorithm we’ve developed for a novel inkjet nail printer. The algorithm we used previously for this suffers from visible desaturation since it only exploits the part of the printer gamut that overlaps with the sRGB gamut. To solve this issue, we add a step we call gamut alignment, which enables the printer to fully exploit the entire printer gamut. We show digitally simulated gamut mapped images to illustrate that the proposed GMA indeed produced better saturated gamut mapped images.
Nowadays, inkjet printers are widely used all around the world. But how do they transfer the digital image to a map that can control nozzle firing? In this paper, we briefly illustrate that part of the printing pipeline that starts from a halftone image and end with Hardware Ready Bits (HRBs). We also describe the implementation of the multi-pass printing method with a designed print mask. HRBs are used to read an input halftone CMY image and output a binary map of each color to decide whether or not to eject the corresponding color drop at each pixel position. In general, for an inkjet printer, each row of the image corresponds to one specific nozzle in each swath so that each swath will be the height of the printhead [1]. To avoid visible white streaks due to clogged or burned out color nozzles, the method called multi-pass printing is implemented. Subsequently, the print mask is introduced so that we can decide during which pass each pixel should be printed.