Glossary

Bidirectional reflectance distribution function

Diagram showing vectors used to define the BRDF.

“The bidirectional reflectance distribution function (BRDF) is a function of four real variables that defines how light is reflected at an opaque surface. It is employed in the optics of real-world light, in computer graphics algorithms, and in computer vision algorithms.”

~ Wikipedia on BRDF

A BRDF model is a 7 dimensional model containing geometry, textures and reflectance of the subject.

The seven dimensions of the BRDF model are as follows:

• 3 cartesian X,Y,Z
• 2 for the entry angle
• 2 for the exit angle of the light.

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Covert modeling

Covert modeling refers to both covertly modeling aspects of a subject i.e. without express consent.

Main known cases are

• Covertly modeling the human appearance into 7-dimensional [[#Bidirectional reflectance distribution function|]] model or other type of model.
• Covertly modeling the human voice

There is work ongoing to model e.g. human's style of writing, but this is probably not as drastic a threat as the covert modeling of appearance and of voice.

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Deepfake

“Deepfake (a portmanteau of "deep learning" and "fake") is a technique for human image synthesis based on artificial intelligence. It is used to combine and superimpose existing images and videos onto source images or videos using a machine learning technique called a "generative adversarial network" (GAN).”

~ Wikipedia on Deepfakes

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Digital look-alike

When the camera does not exist, but the subject being imaged with a simulation of a (movie) camera deceives the watcher to believe it is some living or dead person it is a digital look-alike.

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Digital sound-alike

When it cannot be determined by human testing, is some synthesized recording a simulation of some person's speech, or is it a recording made of that person's actual real voice, it is a digital sound-alike.

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Generative adversial network

“A generative adversarial network (GAN) is a class of g systems. Two neural networks contest with each other in a zero-sum game framework. This technique can generate photographs that look at least superficially authentic to human observers, having many realistic characteristics. It is a form of unsupervised learning]].”

~ Wikipedia on generative adversarial network

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Light stage

The ESPER LightCage - 3D face scanning rig is a modern light stage

“A light stage or light cage is equipment used for shape, texture, reflectance and motion capture often with structured light and a multi-camera setup.”

~ Wikipedia on light stages

Media forensics

Media forensics deal with ascertaining genuinity of media.

“Wikipedia does not have an article on w:Media forensics”

~ juboxi on 2019-04-05

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Synthetic terror porn

Synthetic terror porn is pornography synthesized with terrorist intent. Synthetic rape porn is probably by far the most prevalent form of this, but it must be noted that synthesizing consentual looking sex scenes can also be terroristic in intent and effect.