US 6,271,940 B1 · Color negative scanning and transforming into colors of original scene

Abstract

An apparatus and a method are disclosed for digitizing a color negative picture and correcting the image signals in a way that they are linearly related to the luminance of the photographed scene for grey tones in the scene. A second embodiment allows obtaining on the basis of the color-corrected image signals a reproduction of true color of the scene on a color display unit. For determining the correction, use is made of the characteristic system curve indicating for each of the color components the relation between the luminance of a neutral color swatch in the scene and the density sensed by the scan system. Several methods for drafting said system curve are described. Furthermore, the way of obtaining the color-corrected image signals by means of a color transformation and the way of determining the transformation are explained.

Claims10

Dependent claims

A method for generating digital colour values, representing an original scene from a colour negative image of the original scene recorded onto an image carrier, said original scene including at least one neutral colour area, comprising the following steps:

scanning said colour negative image with a colour image scanner;
separating the colour negative image in a plurality of colour components;
converting each colour component into a plurality of electrical colour values, each electrical colour value corresponding to a portion of the colour negative image;
establishing a relation between the plurality of electrical colour values of each colour component and a luminance of the at least one neutral colour area;
and,
transforming said plurality of electrical colour values into a plurality of corresponding digital colour values according to said relation.

3 more elements

A colour image scanner for scanning a colour negative image of an original scene recorded onto a transparent image carrier, wherein the scene includes at least one neutral colour area, the scanner comprising:

an illuminating lamp emitting light in a broad spectrum for passing through the transparent image carrier such that the illuminating light is filtered by the colour negative image recorded thereon;
a plurality of colour filters for filtering the illuminating light after it has passed through the image carrier thereby separating the illuminating light into a plurality of colour components, one colour component corresponding to each of the plurality of colour filters;
a photosensitive member illuminated by the filtered illuminating light from each of the plurality of colour filters, said photosensitive member providing an electrical signal in proportion to an illuminance level of the filtered illuminating light falling thereon;
and,
a processing system for generating a plurality of electrical colour values according to the electrical signal received from the photosensitive member, each electrical colour value corresponding to a portion of the colour negative image, said processing system being configured to establish a relation between the plurality of electrical colour values of each colour component and a luminance of the at least one neutral colour area.

2 more elements

Dependencies are inferred from the claim text.

Color negative scanning and transforming into colors of original scene

Life of this patent

Color negative scanning and transforming into colors of original scene

Life of this patent

Abstract

Claims10