Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2001-11-13
2003-10-07
Nguyen, Lamson (Department: 2861)
Incremental printing of symbolic information
Ink jet
Controller
Reexamination Certificate
active
06629746
ABSTRACT:
This application claims priority under 35 U.S.C. §§119 and/or 365 to 00 124 253.6 filed in Europe on Nov. 10, 2000; the entire content of which is hereby incorporated by reference.
FILED OF THE INVENTION
The present invention relates to processes for the reduction of artefacts in the reproduction or display of images, especially photographic images which include an multitude of image points. The invention further relates to image reproducing devices, such as printers (inkjet printers, laser printers, thermal printers, and so on), monitors (for example, ICD monitors or cathel gray monitors or CRT monitors) and devices for the capturing of images on radiation sensitive (especially light sensitive) media (for example photographic paper), for example photoprinters or DMD's (digital mirror devices) functioning with lasers or monitors. Particularly, the invention relates to image reproducing devices which reproduce photographs, whereby the reproduction of photographs also includes the generation of photographs on media, especially photographic paper or normal paper. The image data are especially photographic image data, which were captured with an image capturing apparatus, such as, for example, a photographic apparatus, a camera (for example film camera, digital camera, video camera).
The invention further relates to photographic labs, especially minilabs, which use an image reproducing device, an error correction process or a large space lab.
The invention relates further to programs which carry out error correction process.
BACKGROUND ART
A high quality is demanded especially in the photographic field for images which are based on digital image data. A series of different image reproducing devices are used for the reproduction, especially in the photographic field, besides monitors, especially image reproducing devices which will reproduce the image on a medium. Different printers or writing devices are especially used which reproduce images on radiation sensitive media (light sensitive media) by beams (for example, light beams or particle beams or electrode beams). It is common to all image reproduction techniques that image data which define the image to be reproduced, are converted into image data which are suited for the control of the image reproducing device so that the image reproducing device produces the most exact as reproduction possible of the image defined by the original image data.
The present invention relates to devices and processes wherein an image (especially bitmap image) is reproduced with a multitude of individual image points and the image data describe the nominal properties of the individual image points. The properties of the image points are appearance properties, which describe the visual impression which the image point at a certain position in an image has on a human observer, or which, in other words, influence or determine the visual or optical appearance of the image point in the image. The appearance properties of the image points include especially the geometric properties of the image point, such as its relative position (distance) to the adjacent image points or deviation from a nominal position and image point size and image point shape. Properties of the image point are, for example, also its color value or its position in the color space, which can be described, for example, by a lab vector, such as, for example, color, color saturation, color tone, brightness, luminance, and so on. The appearance properties can also be defined for a defined illumination of the image, for example, with a standard light source (for example. D65) at a given aperture angle. Appearance properties can also be determined by the color values of adjacent image points of an image point and their color interaction for the observer as well as by properties of a medium (for example, glossy paper, matte paper) especially with respect to the reflection of an illumination light.
Prior processes for the image reproduction rely on the image reproducing device always answering the same to each arriving image data, irrespective of the location or position of the image point in the image. For this purpose, so called profiles of the image reproducing device are generated to reproduce, for example, a color defined by the arriving image data in a desired manner. Irrespective of the location where the image point is produced, input GB data are converted, for example, into exiting CMYK data for each image point and in the same manner.
This approach produces satisfying results when the image reproducing device answers in the same manner to incoming image data for each image point to be reproduced. However, this is not the case in reality. For example, in an inkjet printer, not all image points are reproduced at the intended position, with the intended dot size and with the intended color value. The actual appearance properties of the image points therefore do not correspond (depending on the position) with the desired appearance properties. The same applies to the other above-mentioned image reproducing devices. For example, the different lasers of a laser printer can produce different image point sizes or the LCD transistors of the monitor can be unevenly spaced.
In order to prevent such errors in the image reproduction as much as possible, a high mechanical effort is made in order to guarantee the most uniform answer possible of the image reproducing device to all the image points to be produced, or one attempts an averaging of the deviations in the control of the image reproducing device. Examples for ink-jet printers are found, for example, in U.S. Pat. No. 5,844,585 and U.S. Pat. No. 5,289,208, the disclosures of which are hereby incorporated by reference in their entireties.
The problems of the prior art are discussed in more detail in the following with reference to inkjet printers. A frequent problem in inkjet printers is the incorrect placement of image points (dots) which is produced by an incorrect orientation or different ejection speeds of the individual nozzles. Furthermore, the individual nozzles can produce different dot sizes. If several printing heads are used, the exact orientation of the printing heads to one another also constitutes a problem. In order to solve these problems, a frequent cleaning of the nozzles was suggested at least in part A solution for an increase in the accuracy of the mutual orientation and control of the printing heads was suggested (U.S. Pat. No. 5,289,208). Further suggested were multiple printing passes with the same nozzles and in the same printing region (U.S. Pat. No. 5,844,585).
However, with the suggested solutions, the printing speeds decreased in the case of several printing passes, the ink consumption increases in the case of frequent cleaning and the cost increases in the case of an increased mechanical precision.
SUMMARY OF THE INVENTION
It is now an object of the invention to provide an improved image quality in the image reproduction even at a lower mechanical precision of the image reproducing device.
This object is achieved in accordance with the invention with a process for the reduction of artefacts in reproduced images wherein control values for the reproduction of the image points by the image reproducing device are set based on the image data associated with the image points and taking into consideration the influences on the appearance properties of the image points to be reproduced. The influences are determined based on the device characteristics and depending on the position of the image points.
In the process in accordance with the invention, at least part of the appearance properties (such as, for example, color value and/or position deviation) of the individual image points, which result with a specific image reproducing device, are used as the basis for the reduction of artefacts in the image reproduction. It is a further advantageous aspect of the invention that in particular the position dependent influence (image point position) on the appearance properties is considered by way of the characteristic
Keller Guido
Kündig Armin
Waldner Stephan
Burns Doane , Swecker, Mathis LLP
Gretag Imaging Trading AG
Nguyen Lamson
LandOfFree
Reduction of artefacts in reproduced images does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reduction of artefacts in reproduced images, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reduction of artefacts in reproduced images will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3173665