27 lines
1.6 KiB
Markdown
27 lines
1.6 KiB
Markdown
---
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id: facial-landmark
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title: Facial Landmark
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---
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Facial landmarks refer to specific regions of the face, with x, y, and z coordinates for each facial landmark variable indicating where in the image frame that specific region of the face is located.
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<figure>
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<img src="/docs/assets/facial-landmark-1.png" width="500" alt="Visual representation of the facial landmarks calculated by OpenDBM, which relies on OpenFace and OpenCV for its measurements." />
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<figcaption>Visual representation of the facial landmarks calculated by OpenDBM, which relies on OpenFace and OpenCV for its measurements.</figcaption>
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</figure>
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OpenDBM calculates overall change in facial landmark positioning and in doing so measures facial musculature movements at the level of individual facial landmarks. Individual movement of a total of 68 facial landmarks is measured using the raw and derived variables listed in the tables below.
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## Raw Variables
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| Variable | Description |
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| ----------- | ----------- |
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| `fac_lmkXXdisp` | **Landmark displacement.** Frame-wise change in landmark positioning i.e. the euclidean distance in the xyz plane, where XX can be any number between 01 and 68, referring to all individual facial landmarks. |
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## Derived Variables
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| Variable | Description |
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| ----------- | ----------- |
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| `fac_lmkXXdisp_mean` | **Landmark displacement mean.** The mean value of fac_lmkXXdisp for the inputted video. |
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| `fac_lmkXXdisp_std` | **Landmark displacement standard deviation.** The standard deviation value of fac_lmkXXdisp for the inputted video. | |