The development of the toner density sensor for closed-loop feedback laser printer calibration

A new infrared (IR) sensor was developed for application in closed-loop feedback printer calibration as it relates to monochrome (black toner only) laser printers. The toner density IR sensor (TDS) was introduced in the early 1980’s; however, due to cost and limitation of technologies at the time, implementation was not accomplished until within the past decade. Existing IR sensor designs do not discuss/address: • EMI (electromagnetic interference) effects on the sensor due to EP (electrophotography) components • Design considerations for environmental conditions • Sensor response time as it affects printer process speed The toner density sensor (TDS) implemented in the Lexmark E series printer reduces these problems and eliminates the use of the current traditional “open-loop” (meaning feedback are parameters not directly affecting print darkness such as page count, toner level, etc.) calibration process where print darkness is adjusted using previously calculated and stored EP process parameters. The historical process does not have the ability to capture cartridge component variation and environmental changes which affect print darkness variation. The TDS captures real time data which is used to calculate EP process parameters for the adjustment of print darkness; as a result, greatly reducing variations uncontrolled by historical printer calibration. Specifically, the first and primary purpose of this research is to reduce print darkness variation using the TDS. The second goal is to mitigate the TDS EMI implementation issue for reliable data accuracy

Evaluation of the press calibration methods by simulation

Press calibration is an approach to adjust the behavior of ink, paper, and press with the use of a CTP platemaking system to achieve a specified reference printing condition. Reference printing condition defines a common color space for color image data exchange between various output devices. The advantage of a reference printing condition is to improve color image quality and reduce cost and time. Corner points of the color gamut, TVI curves, and grey reproduction are the three significant elements in a reference printing condition, which make them essential in press calibration. There are usually two press runs in press calibration. The first press run (Run 1) is to adjust ink system of a press to achieve the color gamut conformance to the reference aims with linear plates. The second press run (Run 2) is to either adjust tonality or neutrality of the press with curved plates based on the Run 1 printing condition. Thus, the question is whether the two press calibration runs can meet the three requirements achieving full conformance according to the reference aims? This research assessed two cases starting with two real Run 1 printing conditions. In the both cases, ISO Type 1 paper was used and the color gamut was in conformance to the reference CGATS TR006 printing condition. Run 2 was a simulated calibration press run with the adjustment of either tonality or neutrality of the press. The use of A-to-B tag and B-to-A tag of the Run 1 ICC profile with absolute colorimetric rendering intent was the essential idea to simulate a calibrated Run 2 printing condition. The advantage is that no printing drafts would occur in the simulation approach, which guarantees repeatability from Run 1 to Run 2. The calibration results were verified to be in conformance first before other assessments. In other words, TVI curves of the TVI-based calibrated results were verified to be in conformance first before grey reproduction conformance was assessed; and grey reproduction of G7-based calibration results was verified to be in conformance first before TVI curves\u27 conformance was assessed. The research results show that (1) if deviations of TVI curves and grey reproduction in Run 1 printing conditions are close to the reference aims, either of the two calibration methods can achieve full conformance; and (2) if discrepancies of TVI curves and grey reproduction conformance in Run 1 printing conditions are far from the reference aims, a third requirement may not be in conformance unless adjustments will be iterated within specified tolerances

Project Tech Top study of lunar, planetary and solar topography Final report

Data acquisition techniques for information on lunar, planetary, and solar topograph

A Colorimetric investigation of soft proofing

The color proof has become one of the most important tools for quality control in the printing industry today3. Customers, publishers, separators, and printers depend upon its accuracy for indicating the quality of separations. The color proof is the most practical method for communicating how the color should appear and is easy to understand and use for comparison. The analog color proof is compared to the original to determine if the desired result has been achieved. The proof is sent to the customer to indicate how the image will appear when printed. If this proof is accepted, it is sent to the press room to indicate what is expected in the final reproduction. The color proof visually simulates how a set of films will print on the final production press with the production inks and stock. However, all too often, what is seen on the proof is not what the customer receives

Calibration Systems of the KATRIN Experiment and Systematics Inherent in the Search for Sterile Neutrinos at the keV Scale

The presence of non-zero neutrino mass is one of the most important discoveries of physics beyond the standard model. Experiments in neutrino oscillation have established the mass splittings and mixing parameters of the (as of now) three known mass states, but the absolute scale of neutrino masses remains a mystery. In addition, evidence has mounted suggesting that the current picture of the three neutrino species may not be complete.The KATRIN (Karlsruhe Tritium Neutrino) experiment aims to measure the neutrino mass to 0.2 eV, representing an order of magnitude improvement in any direct measurement of the absolute scale. KATRIN will accomplish this task by measuring the endpoint spectrum of beta decay electrons from molecular tritium. The high precision beta spectroscopy will be performed via magnetic collimation electrostatic (MAC-E) filter spectroscopy. This measurement technique presents several sources of systematic error. In particular, it is of utmost importance that the activity and column density is of tritium is known to high precision. The presence of backscattered electrons also have the potential to alter the shape of the tritium endpoint. This document contains discussion of these systematic uncertainties, along with the design and construction of calibration systems that aim to reduce those systematics.The question of electron backscattering, and how it applies to the KATRIN measurement has also been explored experimentally for the first time. A measurement has been performed using a scanning electron microscope and custom-designed electrostatic spectrometer to measure the energy spectrum of backscattered electrons close to the tritium endpoint energy. An analysis has also been performed to explore the possible systematics originating from backscattered electrons on a possible keV-scale sterile neutrino search.The electron backscattering experiment has measured Auger electrons from gold in the energy range 6-11 keV produced at a rate of $10^{-4}$ Auger electrons per incident electron. An investigation of proposed keV sterile neutrino search analysis methods show that this rate of Auger electron production is problematic, and work needs to be done to reduce this source of background if a keV-scale sterile neutrino search is to be successful

Automated color correction for colorimetric applications using barcodes

[eng] Color-based sensor devices often offer qualitative solutions, where a material change its color from one color to another, and this is change is observed by a user who performs a manual reading. These materials change their color in response to changes in a certain physical or chemical magnitude. Nowadays, we can find colorimetric indicators with several sensing targets, such as: temperature, humidity, environmental gases, etc. The common approach to quantize these sensors is to place ad hoc electronic components, e.g., a reader device. With the rise of smartphone technology, the possibility to automatically acquire a digital image of those sensors and then compute a quantitative measure is near. By leveraging this measuring process to the smartphones, we avoid the use of ad hoc electronic components, thus reducing colorimetric application cost. However, there exists a challenge on how-to acquire the images of the colorimetric applications and how-to do it consistently, with the disparity of external factors affecting the measure, such as ambient light conditions or different camera modules. In this thesis, we tackle the challenges to digitize and quantize colorimetric applications, such as colorimetric indicators. We make a statement to use 2D barcodes, well-known computer vision patterns, as the base technology to overcome those challenges. We focus on four main challenges: (I) to capture barcodes on top of real-world challenging surfaces (bottles, food packages, etc.), which are the usual surface where colorimetric indicators are placed; (II) to define a new 2D barcode to embed colorimetric features in a back-compatible fashion; (III) to achieve image consistency when capturing images with smartphones by reviewing existent methods and proposing a new color correction method, based upon thin-plate splines mappings; and (IV) to demonstrate a specific application use case applied to a colorimetric indicator for sensing CO2 in the range of modified atmosphere packaging, MAP, one of the common food-packaging standards.[cat] Els dispositius de sensat basats en color, normalment ofereixen solucions qualitatives, en aquestes solucions un material canvia el seu color a un altre color, i aquest canvi de color és observat per un usuari que fa una mesura manual. Aquests materials canvien de color en resposta a un canvi en una magnitud física o química. Avui en dia, podem trobar indicadors colorimètrics que amb diferents objectius, per exemple: temperatura, humitat, gasos ambientals, etc. L'opció més comuna per quantitzar aquests sensors és l'ús d'electrònica addicional, és a dir, un lector. Amb l'augment de la tecnologia dels telèfons intel·ligents, la possibilitat d'automatitzar l'adquisició d'imatges digitals d'aquests sensors i després computar una mesura quantitativa és a prop. Desplaçant aquest procés de mesura als telèfons mòbils, evitem l'ús d'aquesta electrònica addicional, i així, es redueix el cost de l'aplicació colorimètrica. Tanmateix, existeixen reptes sobre com adquirir les imatges de les aplicacions colorimètriques i de com fer-ho de forma consistent, a causa de la disparitat de factors externs que afecten la mesura, com per exemple la llum ambient or les diferents càmeres utilitzades. En aquesta tesi, encarem els reptes de digitalitzar i quantitzar aplicacions colorimètriques, com els indicadors colorimètrics. Fem una proposició per utilitzar codis de barres en dues dimensions, que són coneguts patrons de visió per computador, com a base de la nostra tecnologia per superar aquests reptes. Ens focalitzem en quatre reptes principals: (I) capturar codis de barres sobre de superfícies del món real (ampolles, safates de menjar, etc.), que són les superfícies on usualment aquests indicadors colorimètrics estan situats; (II) definir un nou codi de barres en dues dimensions per encastar elements colorimètrics de forma retro-compatible; (III) aconseguir consistència en la captura d'imatges quan es capturen amb telèfons mòbils, revisant mètodes de correcció de color existents i proposant un nou mètode basat en transformacions geomètriques que utilitzen splines; i (IV) demostrar l'ús de la tecnologia en un cas específic aplicat a un indicador colorimètric per detectar CO2 en el rang per envasos amb atmosfera modificada, MAP, un dels estàndards en envasos de menjar.

Handbook of Optical and Laser Scanning

From its initial publication titled Laser Beam Scanning in 1985 to Handbook of Optical and Laser Scanning, now in its second edition, this reference has kept professionals and students at the forefront of optical scanning technology. Carefully and meticulously updated in each iteration, the book continues to be the most comprehensive scanning resource on the market. It examines the breadth and depth of subtopics in the field from a variety of perspectives. The Second Edition covers: Technologies such as piezoelectric devices Applications of laser scanning such as Ladar (laser radar) Underwater scanning and laser scanning in CTP As laser costs come down, and power and availability increase, the potential applications for laser scanning continue to increase. Bringing together the knowledge and experience of 26 authors from England, Japan and the United States, the book provides an excellent resource for understanding the principles of laser scanning. It illustrates the significance of scanning in society today and would help the user get started in developing system concepts using scanning. It can be used as an introduction to the field and as a reference for persons involved in any aspect of optical and laser beam scanning

Print engine color management using customer image content

The production of quality color prints requires that color accuracy and reproducibility be maintained to within very tight tolerances when transferred to different media. Variations in the printing process commonly produce color shifts that result in poor color reproduction. The primary function of a color management system is maintaining color quality and consistency. Currently these systems are tuned in the factory by printing a large set of test color patches, measuring them, and making necessary adjustments. This time-consuming procedure should be repeated as needed once the printer leaves the factory. In this work, a color management system that compensates for print color shifts in real-time using feedback from an in-line full-width sensor is proposed. Instead of printing test patches, this novel attempt at color management utilizes the output pixels already rendered in production pages, for a continuous printer characterization. The printed pages are scanned in-line and the results are utilized to update the process by which colorimetric image content is translated into engine specific color separations (e.g. CIELAB-\u3eCMYK). The proposed system provides a means to perform automatic printer characterization, by simply printing a set of images that cover the gamut of the printer. Moreover, all of the color conversion features currently utilized in production systems (such as Gray Component Replacement, Gamut Mapping, and Color Smoothing) can be achieved with the proposed system

Innovative color management methods for RGB printing

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (leaf 50).Re-calibrating a printer in response to systematic changes is measurement and labor intensive. In this study, a fast correction method with cycle-to-cycle control was proposed. The process includes two steps: the creation of look-up table using a characterization data set, and image color compensation in conjunction with Windows printing architecture. Several types of correction models for determining printer characterization were proposed and evaluated, including polynomial models and neural network models. The most successful of these methods was the quadratic spline interpolation model, which removed most errors introduced by the changes of colorant and printing substrate. A significant reduction in error was realized by incorporating this technique into the color management program.by Wei Dong.M.Eng