Image processing of pixelised images
AssigneeOce-Technologies B.V.
InventorsHubertus M.J.M. Boesten, Peter M. Van Der Sanden
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Abstract
An image processing system and method are provided for judging whether a pixelised image or a part thereof is a monochrome or a colour image. To increase the reliability of the judgement, instead of making the judgement on the level of an individual pixel, the judgement is made for substantially all the pixels of the image or image part at the same time by analyzing the cumulative histogram, wherein the distance of each pixel to the gray axis versus the logarithm of the cumulative pixel count is plotted. An advantage of the present system and the method of operating this system is their high sensitivity for detecting small colour objects in monochrome images.
Claims19
An image processing method for processing a pixelised image, the method comprising the steps of:
- analyzing pixel data representative of said pixelised image in a colour space and based thereon determining a gray axis defined as a straight line connecting a white point with a black point;
- determining for each pixel of said pixelised image the shortest distance to said gray axis;
- forming a cumulative histogram by plotting for the pixels of said pixelised image a value of said shortest distance versus a cumulative pixel count being the number of associated pixels having at least said value of said shortest distance;
- and
- analyzing a relationship between the pixels in said cumulative histogram and based thereon judging whether said pixelised image is to be processed as a monochrome image or a colour image.
An image processing system for processing a pixelised image, the system comprising:
- a pre-processor for analyzing pixel data representative of said pixelised image in a colour space and based thereon determining a gray axis defined as a straight line connecting a white point with a black point, and determining for each pixel of said pixelised image the shortest distance to said gray axis;
- an analyzer for analyzing a relationship between the pixels of said pixelised image in a cumulative histogram, said cumulative histogram being formed by plotting for the pixels of said pixelised image a value of said shortest distance versus a cumulative pixel count being the number of associated pixels having at least said value of said shortest distance;
- and
- a judging unit for judging, based on said relationship between the pixels in said cumulative histogram, whether said pixelised image is to be processed as a monochrome image or a colour image.
Dependencies are inferred from the claim text.