As the number of iterations increases, it's a good idea to decrease the speed to avoid issues.įirst order derivatives are linked to simple diffusion, such as hazing and light leaks. The speed of diffusion is a general factor applied to all strengths settings at once. If they happen, you need to dampen your derivatives (strength and/or regularization). Overshoots cause artifacts, such asnoise, gradient reversals (halos, fringes), etc. The value of the regularization drives the speed of the transition between the low and high magnitude. * low magnitude derivatives (zero and close) are never affected by the regularization parameter. * low values apply a lower (or even close to none) penalty to derivatives of high magnitude, allowing stronger effects but also overshoots. * high values apply an higher penalty to derivatives of high magnitude, to avoid overshoot and gradient reversals around edges, * low values makes the 2D derivatives more uniform (isotropic), in a radial direction, more like usual blurs, * high values make the 2D derivatives more directional (anisotropic), following a direction perpendicular to the steepest gradient * negative values make that derivative more oscillatory (sharpening), * positive values make that derivative smoother (diffusion), Details below.Įvery order of derivatives comes with 3 sliders: 1 to 2 iterations are ok, up to 4 iterations is meh, more than 4 iterations is something you can do before taking a walk. The module is slow… Not much I can do besides providing an OpenCL kernel. The filter is applied on linear RGB so it's really suited to remove non-uniform lens blur. Notice that it respects the depth of field fairly well and does not display halos. Before/After 1/After 2/After 3 (images at 1:1): For this, the module is put right after exposure. This seems to make dt crash sometimes, even though it's hard to know what is responsible for the crashes these days.ĭeblur. This is achieved by underlaying a framing module, for which I had to remove the iop_order fences in rawoverexposed.c and finalscale.c. The motivation for this module was to spill image colors outside of its borders, as a special effect for prints: highlights inpainting (although I'm not convinced by the results). anisotropic diffusion, or directional blur if you prefer, propagating colors in the perpendicular direction of edges, (so, eitherĥ. blind deconvolution by gradient descent, following the steepest gradient direction,Ģ.

The module comes with 4 presets to showcase what it can do, since it's quite close to physics and can be used in a variety of situations:ġ. Basically, it allows to make pixels spill (or un-spill) on their neighbours. It's very close in logic to the filmic highlights reconstruction. The algorithm is adapted for a wavelets framework, which makes it super slow (OpenCL incoming ASAP) but allows to include spatiality in the parameters. However, I have found that it doesn't really reconstruct anything unless you apply a large amount of iterations, which is not compatible with dt's 'realtime'-ish purpose. This implements an heat transfer partial derivative equations solver, adapted fr … om and originally meant for image inpainting and reconstruction.

Gimp gradient magnitude