{'fraction_non_alphanumeric': 0.01637107776261937, 'fraction_numerical': 0.0034106412005457027, 'mean_word_length': 5.06198347107438, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
The Perceptibility of Random Streaking

A printer with good macrouniformity is capable of producing large uniform areas that would occur in business graphics. One class of macrouniformity defects arises from some aspect of marking that varies in space (such as inkjet printhead uniformity) or time (such as noise in a gear). These process deficiencies can cause visible print density variations that appear as bands or streaks. The change in print density is quantified by measuring the color variation perpendicular to the direction of the banding or streaks. The print density variations can be categorized into three classes: isolated, periodic, or random. Experimental measurements on prints show that often the Fourier spectrum of the print density is characterized by a 1/f noise spectrum. This presentation reports on a psychophysical study on the perceptibility of 1/f noise. A series of monochrome images with random streaks characterized by a 1/f noise frequency spectrum were created on a high quality printer which created very little additional noise. The samples differ by the amplitude of the noise and the average optical density of the print. The perceptibility of the streaks was evaluated by 15 observers. The perceptibility depended only on the standard deviation of L* and was independent of the average density. People are very sensitive to this type of streaks, consistent with published data for sensitivity to sinusoidal lightness variation.