Dot placement analysis using a line scan camera and rigid body rotation

Printer manufacturers design print heads and halftone patterns to result in specific types of image characteristics. Many image quality artifacts are a result of differences in actual dot placement from intended dot placement. Quantifying dot placement variations can be a complex endeavor requiring image capture at high magnification for adequate sampling. Large dot fields are imaged in pieces, which requires re-stitching of images prior to assessment, and extensive post processing to calculate actual dot positions compared with intended positions. This paper discusses a novel approach to dot placement analysis. This method includes a single, high magnification image, which is captured using a line-scan camera. Once the image is captured, the image is analyzed using principles of rigid body rotation to match a set of actual dot positions to a template of expected positions. Using this method, errors in dot placement can be assessed rapidly without errors that stem from image stitching.