Tone Reproduction Research Articles

Assessment of a CRT Display System

The use of cathode ray tube (CRT) monitors and graphics cards for the display of pictorial images is common. Certain applications require the characteristics of the display device or medium to be accurately understood. One such application is the use of CRT based displays in experiments involving subjective analysis of viewed images. In this paper we describe a series of experiments performed to characterize a display device used in our laboratories prior to its use in a subjective assessment experiment. The tone reproduction characteristics are studied using transfer functions and gamma. Colour reproduction is studied in temporal and spatial dimensions. Finally, spatial effects are characterized by use of modulation transfer function (MTF) analysis.

Resolution Performance of Images Printed by Laser Dye Thermal Transfer

Microscopic optical image density and resolution performance are discussed for laser thermal transfer printing of the dye sublimation type. This printing method provides high resolution because of the high converging property of the laser beam. In this study, optical density profiles of line images printed by dye sublimation type laser thermal transfer printing were measured and compared with images of the wax type in order to clarify the spread of the printed dots. These profiles were explained numerically, using tone reproduction curves. Resolution performance was evaluated, quantitatively, and the maximum resolution was found to be 10,160 dpi. This value was confirmed by the printed microcharacters. Laser dye transfer printing is feasible for printing not only full-color images, but also fine patterns and microcharacters.

静電誘引形インクジェットの飛翔インクが階調画像記録に及ぼす影響の基礎的検討

静電誘引形インクジェットの飛翔インクが階調画像記録に及ぼす影響の基礎的検討

An MTF Analysis of Papers

Resolution and tone reproduction characteristics of all hardcopy images on paper are significantly influenced by the way light scatters in the paper. However, little has been published on experimental techniques for measuring light scattering and resolution characteristics of paper. Three experimental techniques are discussed in the current work. The first is a direct measure of paper MTF by microdensitometric scans of illuminated edges projected onto the paper. This technique is tedious and of intrinsically low precision. The second technique is based on Kubelka-Munk theory and derives MTF behavior from the Kubelka-Munk equations and experimental measurements of paper reflectance. This technique has the advantage of relating paper MTF to the fundamental metrics of light scattering and light absorption.However, the accuracy of the technique is questionable due to the assumptions intrinsic to Kubelka-Munk theory. The third technique involves modeling the Yule-Nielsen effect of optical dot gain and fitting the model to experimental data. The data are generated by image analysis of idealized halftone patterns formed by placing high-resolution halftone line screens in close mechanical contact with the paper under analysis. This technique is shown to provide estimates of paper MTF with significantly higher precision than traditional microdensitometry scans of illuminated edges. Experimental data are collected for a wide variety of hardcopy substrates, and the results are used to examine some of the assumptions inherent in applying Kubelka-Munk theory to papers.

Digital image publication for backscatter SEM micrographs

A number of limitations impede visualization and interpretation of backscatter SEM images reproduced photographically in technical journals and proceedings. The size of the image presented is often too small to visualize all of the details discussed by the author. Often the loss of contrast and of detail in the half tone reproduction processes used severely limits the information actually conveyed to the reader. In contrast, digital images can be readily reproduced in any desired size without loss of detail. Such images can be readily obtained, stored and manipulated (if necessary) in computer files, and printed out by standard laser printers. The writer is of the opinion that the publication of such digital images instead of conventional photographic reproductions vastly increases the clarity and effectiveness of the visual information actually transmitted to the reader. Several examples of backscatter SEM images of concrete are provided to illustrate the potentials of this method.

ハードコピー ハードコピーの階調再現

ハードコピー ハードコピーの階調再現

Gamma Correction and Tone Reproduction in Scanned Photographic Images

Gamma has slightly different meanings in photo graphy and video, and the convergence of these two technologies in digital imaging has produced some confusion regarding the concept of gamma-corrected values in digital image files. This article reviews the concept of gamma as a means of quantifing one characteristic of an imaging system and examines the rationale for using gamma correction in scanned photo graphic images. It suggests one way in which gamma correction can be incorporated into a procedure for standardizing the relationship between digital file values and densities on color negatives

Digital halftoning by iterative isotropic error feedback

An error diffusion scheme for digital halftoning is proposed. The scheme is an iterative and isotropic error feedback process. Also, to compensate for the nonlinear tone reproduction by laser printers due to ink drop overlaps, we incorporate Pappas-Neuhoff's simplified printer model into the new error diffusion scheme. It appears that the proposed halftoning technique enhances the perceived tone continuity of halftone hard copies, and it alleviates the objectionable structured halftone textures of some existing methods. In addition, a mechanism is suggested to preview a halftone print on a gray-level CRT monitor. The user can interactively set the desired brightness of the halftone print and balance image contrast and tone continuity, which are two mutually exclusive subjective criteria for halftone reproduction.

Tone reproduction for realistic images

Radiosity and other global illumination methods for image synthesis calculate the real world radiance values of a scene instead of the display radiance values that will represent them. Though radiosity and ray tracing methods can compute extremely accurate and wide-ranging scene radiances, modern display devices emit light only in a tiny fixed range. The radiances must be converted, but ad-hoc conversions cause serious errors and give little assurance that the evoked visual sensations are truly equivalent. Sensation-preserving conversions for display, already known in photography, printing, and television as tone reproduction methods, are discussed. Computer graphics workers can apply the existing photographic methods, but may also extend them to include more complex and subtle effects of human vision using the published findings of vision researchers. Ways of constructing a sensation-preserving display converter, or tone reproduction operator, for monochrome images are demonstrated. >

Tone Reproduction by Intensity Modulated Laser Scanning Exposure (II)

Tone Reproduction by Intensity Modulated Laser Scanning Exposure (II)

インクジェットプロッタによる階調画像再生

インクジェットプロッタによる階調画像再生

Pulse Laser Observation of Electrostatically Extracted Ink Jet and its Application to Tone Reproduction

Pulse Laser Observation of Electrostatically Extracted Ink Jet and its Application to Tone Reproduction

Tone Reproduction in Photography

Tone Reproduction in Photography

Tone Reproduction and Color in Printing

Tone Reproduction and Color in Printing

Tone Reproduction by Intensity Modulated Laser Scanning Exposure

Tone Reproduction by Intensity Modulated Laser Scanning Exposure

ジグザグ走査を利用した静電誘引形インクジェットの階調画像再生

ジグザグ走査を利用した静電誘引形インクジェットの階調画像再生

Half Tone Reproduction in Imaging

Half Tone Reproduction in Imaging

インクジェットのレーザ観測と階調画像再生

インクジェットのレーザ観測と階調画像再生

Computer Simulation for Tone Reproduction Properties of Dot with Microscopic Edge Shape Fluctuations.

Computer Simulation for Tone Reproduction Properties of Dot with Microscopic Edge Shape Fluctuations.

The Characteristic Curve

Hurter and Driffield used the char-acteristic curve as a convenient way of expressing the yield of silver following exposure and subsequent development of the photographic emulsion. Investigators, including Hurter and Driffield, have derived useful parameters from experimentally determined characteristic curves and a number of these parameters are in common use to this day as descriptors of emulsion performance. Attempts have been made, by a number of workers, to fit specific mathematical functions to characteristic curz’es and, in some of the more recent examples, to use the results for the elucidation of fundamental latent-image mechanisms. This work at the microscopic level has been matched by macroscopic studies of tone reproduction, the investigation of preferred tone reproduction, and the construction of materials, for special purposes, with unusual characteristic curve shapes. Characteristic curves of colour reproduction systems are also used in both the assessment of conventional properties, such as speed and contrast, and the study of mechanisms at work within colour emulsions during processing. These aspects of the characteristic curve are reviewed, together with illustrative examples, in this paper.