CoreImage

Core Image Colorspace?

I've made a macro utilizing the CIToneCurve node to offer similar functionality to what you would get out of levels in Photoshop. More recently, I decided to try to write a CIFilter node to do the same thing. I THINK it worked, but the results differ between the two.

The one I wrote in the CIFilter gets darker much faster, but aside from that, the results are pretty similar. The details for the CIToneCurve node say that "The curve is applied in a perceptual (gamma 2) version of the working space." The Core Image Filter makes no mention of color space though, so I'm attributing this difference in results to the Core Image Filter calculating in linear light space, but I'm not sure. However, if this is true, I think it may be worth going back and replacing the tone curve macro with the CIFilter in some of my previous projects.

Would anyone be willing to step in here and confirm my suspicion?

I've attached a reference Quartz Document with an exploded version of the aforementioned macro, the CIFilter, and a multiplexer to quickly compare results between the two. (feel free to use any resource contained within any of your own projects)

Peptide Synthesis (Composition by smokris)

Download (12.78 KB)

Chained Hexagonal Pixellate CoreImage filters with not-quite-synchronized Interpolation behaving in a vaguely-fractal-like manner.

Image Energy (Composition by smokris)

Download (2.88 KB)

Performs a 2D spatially-restricted normalization of the input image, to provide an even-contrast output image.

Useful for getting some discernable output, if you have some random image that's either really dark or really bright. Possibly also useful as preprocessing for some computer-vision algorithms.

TransparentLight image addition filter (Composition by bbinkovitz)

Download (9.35 KB)

This is a filter for superimposing images on one another. It uses a multiply superimposition method, making for opaque blacks and transparent whites. (If you want a version with transparent blacks, see TransparentDark)

It also finds the shortest dimension of each image and scales the larger one down to that dimension. Aspect ratio is not preserved in this version. I'm hoping to add that at some point though.

Enjoy.

TransparentDark image multiply filter (Composition by bbinkovitz)

Download (9.34 KB)

This is a filter for superimposing images on one another. It uses an additive method, making for opaque whites and transparent blacks. (If you want one with transparent whites, see TransparentLight)

It also finds the shortest dimension of each image and scales the larger one down to that dimension. Aspect ratio is not preserved in this version. I'm hoping to add that at some point though.

Enjoy.