Eastman-kodak Company

Donald C Bellis, Jr

Kenneth Alan Parulski

Edward J Giorgianni

Robert H Hibbard

Stephen E Johnson

Elizabeth McInerney

A technique for improving the tone and color reproduction of print and slide images which are photographed onto color negative film, scanned by a Photo CD negative scanner and transferred onto Photo CD discs is disclosed. The technique incorporates a calibration method for (1) producing color negatives (or slides) using normal scanner calibration targets, (2) producing controlled prints from the negatives, (3) re-photographing the prints (or slides) onto a second color negative film, and (4) performing the normal scanner calibration using this second 'cascaded' film. The calibration step not only 'compensates for' the second color negative film (as is the case when calibrating for 'normal' film exposed from the original scenes) but also 'compensates for' the first negative film 'print through' (or slide) characteristics. This means that the image data recorded on the Photo CD disc will more closely resemble the data which would be produced if the original scene had been photographed on color negative film and scanned directly.

Method and apparatus for forming a source-independent image data metric

The present invention involves taking a three color signal produced by an electronic color image sensor, such as the Kodak KAF-1400 sensor with a 3G CFA filter, and performing additive-type color correction processing in a linear domain suitable for performing additive-type color correction. The additive-type processing can be performed by a matrix multiplier using three 3 element correction equations. The linear color corrected signals are converted into a domain, such as the log domain, suitable for performing subtractive-type color correction. Subtractive-type color correction is performed using three 3 element correction equations, or three 9 element correction equations. The color corrected sigtnals are then converted to an appropriate format for input to a color printer. To reduce noise enhancement problems, the color correction is performed on lowpass color signals, and the color corrected lowpass signals are combined with the original high frequency color signals. To enhance the sharpness of the color print, edge enhancement is performed in a three color enhancement space using an appropriately quantized and filtered green color signal, and coring and clipping type noise removal.

Method and apparatus for improving the color rendition of hardcopy

An additive display is driven from a digital source, such as a frame memory, to produce red and blue luminances that exceed the respective white point luminances of the display, thus producing saturated colors including red and blue and accordingly extending the gamut of the display system. The signals input to the frame memory are initially processed by a circuit, such as a color matrix, that is capable of corrections exceeding the white point of the image source. The processed signals are then encoded with more 'headroom' for exceeding the respective white points of red and blue color values than for green color values. In one embodiment, the full red and blue bit resolution is bit-shifted and stored in the frame memory, with the red and blue white points stored as lesser code values than the green white point. The display drive signals produced from the encoded color values are then equalized for a common white point signal value before being applied to the additive display, such as a color CRT monitor.

Growing community of inventors

Rochester, NY, United States of America

Donald C Bellis, Jr