Hewlett-packard Development Company, L.p.

Hewlett-packard Company

Robert D Blanton

Gregory D Nelson

Otto Kenneth Sievert

Otto K Sievert

David Bradley Short

Patrick J Chase

Padmanabhan Ramchandran

Steve T Breidenbach

Shawn B Nielson

Michael Hall

Joseph E Powell

Hamadi Jamali

In one example, a projection capture system includes: a visible light projector to project a pattern on to a surface of a GUI control object placed on or above a work surface; a visible light camera to capture an image of the pattern projected on to the surface of the control object; and a controller operatively connected to the projector and the camera. Programming on the controller determines (1) a lateral position of the pattern relative to a reference position associated with the work surface based on the pattern image captured by the camera and (2) a height of the pattern above the work surface based on the lateral position of the pattern.

Determining position in a projection capture system

A printing component receives media, applies print imaging thereto, and delivers the media to a first location. The apparatus selectively applies at least one calibration mark as the print imaging. An imaging component receives the imaged media at a second location and produces scan data representative thereof. The apparatus selectively analyzes the at least one calibration mark and produces calibration data.

Printing apparatus calibration

Nonoptical properties of inks can be brought to bear in locating ink that is invisible to an automatic sensor. Physical characteristics of inks as liquids can be exploited to reveal their locations with surprising precision. The system includes an optical sensor. Using ink that is visible to the sensor, a preferably fractional fill pattern is printed on a region of a printing medium. Using ink that is invisible to the sensor, calibration indicia or other patterns are printed on particular portions of the same region. Bleed (running together of the liquids of the two inks) tends to convert the fractional fill pattern into a solid fill, within the particular portions that were also printed with the 'invisible' ink. Resulting optoelectronic signals provide amply high contrast between (1) fractional fill in the particular portions where the 'invisible' ink is applied and (2) the original fractional fill elsewhere. The sensor responds to areas where bleed has converted the fractional fill pattern into a relatively more solid fill. Preferably, to enhance contrast, the visible-ink fractional pattern is printed as aggregations of multiple adjacent pixels, rather than individual, mutually separated pixels--but these aggregations are spaced apart. These two preferences together lead to a pattern that bleeds most effectively of any that were tested. Ideal fill density is roughly twenty-five percent.

Systems and method for determining presence of inks that are invisible

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San Diego, CA, United States of America

Robert D Blanton