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52 lines
1.5 KiB
Elixir
52 lines
1.5 KiB
Elixir
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defmodule PhilomenaMedia.Features do
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@moduledoc """
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Features are a set of 768 weighted classification outputs produced from a
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vision transformer (ViT). The individual classifications are arbitrary and
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not meaningful to analyze, but the vectors can be used to compare similarity
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between images using the cosine similarity measurement.
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Since cosine similarity is not a metric, it is substituted for normalized L2
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distance by the feature extractor; every vector that it returns is normalized,
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and traversing the k nearest neighbors in a vector space index will iterate
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vectors in the same order as their cosine similarity.
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"""
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alias PhilomenaMedia.Remote
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@type t :: %__MODULE__{
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features: [float()]
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}
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defstruct [:features]
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@doc """
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Gets the features of the given image file.
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The image file must be in the PNG or JPEG format.
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> #### Info {: .info}
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>
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> Clients should prefer to use `PhilomenaMedia.Processors.features/2`, as it handles
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> media files of any type supported by this library, not just PNG or JPEG.
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## Examples
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iex> Features.file("image.png")
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{:ok, %Features{features: [0.03156396001577377, -0.04559657722711563, ...]}}
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iex> Features.file("nonexistent.jpg")
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:error
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"""
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@spec file(Path.t()) :: {:ok, t()} | :error
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def file(input) do
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case Remote.get_features(input) do
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{:ok, features} ->
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{:ok, %__MODULE__{features: features}}
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_error ->
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:error
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end
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end
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end
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