Method of Designing Color Transfer Function for Volume Rendering for Color Blindness

Abstract

The invention discloses a volume rendering method for designing a color transmission function for color blindness. The method comprises the following steps of: importing volume data into a volume drawing system, designing the color transmission function and an opacity transmission function, and drawing by using the volume rendering method based on a light ray projection algorithm to obtain a result image; re-coloring the result image by using a re-coloring method for the color blindness; setting a color value which is included by the color transmission function to be unknown, sampling part ofnon-background pixels in a window, respectively projecting light rays to the pixels, accumulating weight values about unknown colors, and thus obtaining linear combinations of the unknown colors; setting each linear combination to be equal to the color of a re-colored image at corresponding pixel position, solving to obtain the unknown colors and constructing a new color transmission function; and drawing the volume data by using the new color transmission function and using a new color fusion operator for the color blindness, and thus obtaining the result image which can be explored by a color blindness observer.

Description

technical field [0001] The invention relates to a method for assisting users in designing a color transfer function suitable for color-blind observers for direct volume rendering, belonging to the fields of volume data visualization and image processing. Background technique [0002] Volume data visualization is widely used as an effective tool for communicating and analyzing volume data. However, about 8% of the total population faces different degrees of visual impairment (color blindness and color weakness). These observers also have the ability to browse and explore volume data. demand. The traditional improvement methods for color-blind observers are mainly based on image recoloring, which are mainly divided into two categories: 1) partial color shifting by setting some parameters; 2) color contrast enhancement optimization for the overall color types contained in the image, Each pixel of the image is then recolored. The former needs to adjust the parameters, the inte...

AI Technical Summary

Problems solved by technology

Since the browsing of volume data is an interactive process, users need to observe the results of volume rendering through operations such as rotation and translation, and the image-based recoloring scheme needs to be optimized for each frame of rendering results, so it usually faces performance problems. problems that prevent users from getting a satisfactory interactive experience

In addition, between two frames of different viewing angles, different image content generates different optimization results, and the change of the optimization results leads to color inconsistencies in the same structural parts in the recolored volume rendering results (color shift problem); When the optimization results of two adjacent frames are different, it may cause the color tone to be reversed (timing inconsistency problem)

In particular, the traditional color addition operator is aimed at the fusion of colors in two RGB color spaces, that is, the R, G, and B components of the two colors are linearly interpolated to obtain a new color, while the visual color perception of color-blind observers The space is two intersecting half planes in the LMS color space (for related techniques, please refer to H.Brettel, F.Vienot, and J.D.Mollon., 1997, Computerized simulation of color appearance fordichromats), so that the fusion color obtained after linear interpolation and The relationship between the two input colors is no longer linear in the visual perception of color-blind observers, so to a certain extent, the fused color will lose the information it should express, and interfere with the exploration of image content by color-blind observers (For example, the color obtained by combining two colors according to a certain opacity using the traditional method may be too close to the color perception distance of one of the original two colors in the visual perception of color-blind observers, resulting in inability to case of distinguishing three different colors, causing an incorrect interpretation of the resulting image)

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