AHD, EAHD and HPHD AHD (Adaptive Homogeneity-Directed), EAHD (Horvath's AHD) and HPHD (Heterogeneity-Projection Hard-Decision) are old methods which are generally slow and inferior to the other methods. IGV is also quite effective at mitigating moiré patterns. They will prevent false maze patterns from appearing, and prevent the image from looking washed-out due to heavy noise reduction.
RAWTHERAPEE 5.3 USER MANUAL ISO
LMMSE and IGV These are recommended when working with very noisy, high ISO images, in conjunction with the Noise Reduction tool. AMaZE can often be slightly superior in recovering details, while DCB can be better at avoiding false colors especially in images from cameras without anti-aliasing filters. DCB DCB produces similar results to AMaZE. RCD RCD ( Ratio Corrected Demosaicing) does an excellent job for round edges, for example stars in astrophotography, while preserving almost the same level of detail as AMaZE. In RawTherapee versions 2.4 and older VNG4 used to be the preferred algorithm for Olympus cameras, as AMaZE didn't exist yet and VNG4 eliminated certain maze pattern artifacts that might have been created by the other methods, but with the introduction of the AMaZE method in RawTherapee 3.0, Olympus users might prefer that instead. This can be useful for diagnostics, but you would not use it for photography.ĪMaZE AMaZE (Aliasing Minimization and Zipper Elimination) is the default demosaicing method, as it yields the best results in most cases. Mono Only useful for users of monochrome cameras, or cameras with the color filter array removed. They are, however, unsupported by RawTherapee.įast Very fast but simple and low quality demosaicing method, not recommended. On a side note, the Foveon X3 sensor does not use a color filter array and so images coming from camera with such a sensor do not need to be demosaiced. Concerning X-Trans cameras, 3-pass (Markesteijn) is generally the best method. The most visible effects of the choice of demosaicing algorithm include the rendering quality of fine detail and the visibility of artifacts in the form of maze-like patterns.Ĭoncerning Bayer cameras, AMaZE is generally the best method for lower-ISO images, while LMMSE or IGV are better for higher-ISO ones. However, as the demosaiced image constitutes the foundation upon which all other tools work, the choice of demosaicing algorithm can have a visually significant effect on the end result, particularly when viewed up close. The differences between them can be subtle - one might need to zoom in to 100% or more to discern them. RawTherapee offers several demosaicing algorithms, each with its own characteristics. and thus half (green) or three-fourths (red, blue) of each color channel consist of a lack of data (black, unexposed photosites, since there is for example only one red-filtered photosite out of every four).ĭisplaying an image from a camera with a Bayer or X-Trans sensor is therefore not straight-forward - the mosaic of discrete data points need to be converted into a cogent color image.There are twice as many green photosites as either red or blue,.
There is no concept of color yet, as each photosite registers only a single electric charge induced by the photons which pass through the filter and strike it,.As each photosite is responsible for capturing only a specific band of light, there are three main problems that need to be dealt with: There is also a filter arrangement called " X-Trans", used by some Fujifilm cameras, with a repetitive 6圆 matrix of patches. The " Bayer filter" is the most common - it uses a repetitive 2x2 matrix of green, blue, red and green patches. In order to capture color, a color filter array (CFA) is placed over the sensor, so that specific photosites register specific wavelengths of light. Most digital cameras use a sensor which contains millions of homogeneous light-sensitive elements, called sensels or photosites.
RAWTHERAPEE 5.3 USER MANUAL HOW TO
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