Quadratically Transformed Luminance Chrominance Spaces

Several color spaces defined in the literature are obtained from the RGB space through non-linear transforms, potentially limiting their applicability in a regularization context. Therefore, in this paper, we introduce three new color spaces, QTLC- r∗2, QTLC- g∗2, and QTLC- r∗g∗, and the corresponding quadratic mappings from the RGB space. To test their uniformity, we use them to consider the image defading problem through a novel two-step technique: first, we define a fast heuristic to restore the natural color saturation; then, we propose a regularization technique to deblur the image. We experimentally observe that presumably thanks to its higher uniformity, the QTLC- r∗g∗ space produces natural-looking images in the reconstruction and should be preferred to the QTLC- r∗2 and QTLC- g∗2 spaces. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.