Mathematica Assert[ ]

I’ve been using my own Assert[] function in Mathematica for quite some time. In Mathematica version 8, it was implemented as a built-in. I skipped version 8, but recently installed version 9. When I first used the new Assert, I was confused: Assert[True] returned unevaluated! I quickly discovered that you need to enable the Assert function through evaluating     On@Assert I found nothing on Google; …

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Mathematica RawArray, ArrayObject

I skipped Mathematica Version 8, going directly from 7 to 9, so I’m not sure exactly when RawArray and ArrayObject were added to Mathematica. These are apparently compact forms, roughly comparable to Packed Array, of lists of: unsigned bytes (“Byte”), unsigned (16‑bit) halfwords (“Bit16”), unsigned (32‑bit) words (“Integer32”, or “Integer”, which maps to “Integer32”), machine float single (“Real32”), and …

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Greyscale charts in video and HD

Nine-step (“EIA”) charts have reflectance values arranged in an exponential relationship, r = 0.030 10^(0.18175 k), where k ranges 0 through 8. The reflectance steps correspond to uniform increments of optical density. These charts are typically called “logarithmic.” Eleven-step (“ITE‑J”) charts are designed to have reflectances that, when imaged by a video camera (having an OECF comparable …

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Gamma in studio and CE

HD content (a Blu‑ray movie for example) is properly and commonly mastered with displays (such as Sony BVM‑D32) having 2.4 gamma, at 100 nt reference white, with about 1 lx ambient illuminance, and a surround of about 1 nt (that is, 1% of reference white, a “very dim” surround). The 2.4 gamma is specified in BT.1886, and is well approximated by …

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