Merge pull request #911 from luxonis/fix_formulas

Fix docs formulas for calibration readers

docs/source/samples/calibration/calibration_reader.rst

@@ -27,7 +27,7 @@ Here's theoretical calculation of the focal length in pixels:
 
 .. math::
 
-  focalLength = width_px * 0.5 / tan(hfov * 0.5 * pi / 180)
+  f_x = \text{width}_x \cdot \frac{1}{\tan \left(\frac{\text{HFOV}_x}{2}\frac{\pi}{180}\right)}
 
 To get the HFOV you can use `this script <https://gist.github.com/Erol444/4aff71f4576637624d56dce4a60ad62e>`__, which also works for wide-FOV cameras and allows you to
 specif alpha parameter.
@@ -36,13 +36,14 @@ With 400P (640x400) camera resolution where HFOV=71.9 degrees:
 
 .. math::
 
-  focalLength = 640 * 0.5 / tan(71.9 * 0.5 * PI / 180) = 441.25
+  f_x = 640 \cdot \frac{1}{\tan \left(\frac{71.9}{2}\frac{\pi}{180}\right)} = 441.25
 
 And for 800P (1280x800) camera resolution where HFOV=71.9 degrees:
 
 .. math::
 
-  focalLength = 1280 * 0.5 / tan(71.9 * 0.5 * PI / 180) = 882.5
+  f_x = 1280 \cdot \frac{1}{\tan \left(\frac{71.9}{2}\frac{\pi}{180}\right)} = 882.5
+
 
 
 

docs/source/tutorials/configuring-stereo-depth.rst

@@ -34,13 +34,13 @@ Let's first look at how the depth is calculated:
 
 .. math::
 
-   depth [mm] = focalLength [pix] * baseline [mm] / disparity [pix]
+   \text{depth[mm]} =f_{x}\text{[px]} \cdot \frac{\text{baseline[mm]}}{\text{disparity[px]}}
 
 Examples for calculating the depth value, using the OAK-D (7.5cm baseline OV9282), for 400P resolution and disparity of 50 pixels:
 
 .. math::
 
-  depth = 441.25 * 7.5 / 50 = 66.19 cm
+  \text{depth} = 441.25 \cdot \frac{7.5}{50} = 66.19 \text{ cm}
 
 `RVC2 <https://docs.luxonis.com/projects/hardware/en/latest/pages/rvc/rvc2.html>`__-based cameras have a **0..95 disparity search** range,
 which limits the minimal depth perception. Baseline is the distance between two cameras of the