Sometimes pithy photographic explanations, although valid and meaningful for the cognoscenti, can need some unpacking for most folk. Consider that Ansel Adams and others have used whole books, with charts, tables, graphs, and examples, just to say “expose for the shadows, develop for the highlights.” Thus it is — possibly, anyway — with photon noise. This post… [Read More]
Search Results for: resampling
Dither and image detail, natural scene
For the past few days, I’ve been trying to determine — yet again, with new criteria — how much read noise is necessary to properly dither an analog to digital converter of a given precision. Specifically, I’m trying to figure out what the relationship is between dither and quantizing precision when resolving detail is the… [Read More]
What’s MTF50 = x look like: sim pix
Last week, I wrote this post on producing images that show visually the effect of image capture blur on Bayer-CFA cameras. I briefly discussed this simulation-based approach: Start out with a slanted edge. Dial in some diffraction, some motion blur, some defocusing, take the captured image, run it through a slanted edge analyzer, and get… [Read More]
Noise performance of downsampling with eliptical weighted averaging
Over on the Luminous Landscape forum, Nicolas Robidoux, Bart van der Wolf, Alan Gibson, and others have been working on developing downsampling algorithms. They’re using the command-line image editor ImageMagick as the engine to do the work, so their methodology is to write scripts that call ImageMagick. Some of their algorithms are producing impressive results,… [Read More]
Comparing downsampling algorithms, Fuji still life
This is the fourth in a series of posts showing images that have been downsampled using several different algorithms Photoshop’s bilinear interpolation Ps bicubic sharper Lightroom export with no sharpening Lr export with Low, Standard, and High sharpening for glossy paper A complicated filter based on Elliptical Weighted Averaging (EWA), performed at two gammas and… [Read More]
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