ADICT: Accurate Direct and Inverse Color Transformation

Abstract

Abstract. A color transfer function describes the relationship between the input and the output colors of a device. Computing this function is difficult when devices do not follow traditionally coveted properties like channel independency or color constancy, as is the case with most commodity capture and display devices (like projectors, camerass and printers). In this paper we present a novel representation for the color transfer function of any device, using higher-dimensional Bézier patches, that does not rely on any restrictive assumptions and hence can handle devices that do not behave in an ideal manner. Using this representation and a novel reparametrization technique, we design a color transformation method that is more accurate and free of local artifacts compared to existing color transformation methods. We demonstrate this method's generality by using it for color management on a variety of input and output devices. Our method shows significant improvement in the appearance of seamlessness when used in the particularly demanding application of color matching across multi-projector displays or multi-camera systems. Finally we demonstrate that our color transformation method can be performed efficiently using a real-time GPU implementation.

Dense sampling of 3D color transfer functions using HDR photography

“…Therefore, our method can also be used in conjunction with previous approaches, for example ADICT [7].…”

“…They use a sparse sampling of 13 3 measurements (with a higher density at lower intensities to accommodate for the nonlinear nature of the function) and linearly interpolate in between them. Sajadi, Lazarov and Majumder suggest using 3D Bézier volumes [7] for interpolation and report that using their method with 9 3 sample points yields comparable results to 16 3 samples with linear interpolation. They further report that highend DSLR cameras' color gamuts are wide enough to directly capture the color transfer function of most projectors, so that a 3×3 matrix may be applied to convert the camera's (RAW) sRGB images to XYZ.…”

Perceptually Based Appearance Modification for Compliant Appearance Editing

“…Our system acquires a model, calibrates the projectors and camera, and captures projector-to-camera light transport similar to [ALY08]. Radiometric calibration is performed using [SLM10] or [ALY08]. Then, a compliant appearance A c is computed for a given target appearance.…”

“…Radiometric calibration is used in AE as a means to increase the accuracy of reproducing colours (e.g. [NPGB03, GPNB04, WB07, GB08, SLM10]). However, radiometric calibration cannot compensate for strong colour changes where an insufficient amount of projector light radiance makes achieving a target colour fundamentally impossible.…”

Practical Non-linear Photometric Projector Compensation

“…The number of required samples can be minimized by sparsely sampling the colors and applying interpolation methods to compute the remaining values. While tri-linear interpolation obviously won't generate satisfying results, more complex interpolation methods as, for example, presented in [17], are able to minimize the errors significantly. This method, however, still requires more than 700 images to be acquired and thus is still not practical, especially if the data has be calculated and stored for each individual pixel.…”