Changes related to #13: Adds focal, fov

visu3d/dc_arrays/camera_spec.py

@@ -107,6 +107,7 @@ class implementation.
       repr=False,
       init=False,
   )
+  focal_length: Tuple[float, float]
 
   @property
   def h(self) -> int:
@@ -118,14 +119,60 @@ def w(self) -> int:
 
   @property
   def hw(self) -> tuple[int, int]:
-    """`(Height, Width)` in pixel (for usage in `(i, j)` coordinates)."""
+    """`(Height, Width)` in pixel (for usage in `(u, v)` coordinates)."""
     return (self.h, self.w)
 
   @property
   def wh(self) -> tuple[int, int]:
-    """`(Width, Height)` in pixel (for usage in `(u, v)` coordinates)."""
+    """`(Width, Height)` in pixel (for usage in `(i, j)` coordinates)."""
     return (self.w, self.h)
 
+  @property
+  def fw(self) -> float:
+    """Focal length (along x-axis) in pixels (for usage in `(i, j)` coordinates)."""
+    return self.focal_length[0]
+
+  @property
+  def fh(self) -> float:
+    """Focal length (along y-axis) in pixels (for usage in `(i, j)` coordinates)."""
+    return self.focal_length[1]
+
+  @property
+  def focal_px_wh(self) -> tuple[float, float]:
+    """Focal length in pixel (`(fw, fh)`)."""
+    return (self.fw, self.fh)
+
+  @property
+  def focal_px(self) -> float:
+    """Unique Focal length in pixels (when fw == fh)."""
+
+    def _err_msg():
+      return (
+          'Cannot get `CameraSpec.focal_px` when fw and fh are '
+          f'different: {self.focal_px_wh}'
+      )
+
+    if self.fw != self.fh:
+      raise ValueError(_err_msg())
+
+    return self.fw
+
+  @property
+  def fov_w(self) -> float:
+    """Field of view (horizontal) in radians (for usage in `(i, j)` coordinates)."""
+    return 2 * self.xnp.arctan(self.w / (2 * self.fw))
+
+  @property
+  def fov_h(self) -> float:
+    """Field of view (vertical) in radians (for usage in `(i, j)` coordinates)."""
+    return 2 * self.xnp.arctan(self.h / (2 * self.fh))
+
+  @property
+  def fov(self) -> float:
+    """Field of view in radians (`(fov_w, fov_h)`)."""
+
+    return (self.fov_w, self.fov_h)
+
   # @abc.abstractmethod
   @property
   def px_from_cam(self) -> transformation.TransformBase:
@@ -300,8 +347,7 @@ def from_focal(
         [0, 0, 1],
     ])
     return cls(
-        K=K,
-        resolution=resolution,
+        K=K, resolution=resolution, focal_length=(focal_in_px, focal_in_px)
     )
 
   @property

visu3d/dc_arrays/camera_spec_test.py

@@ -26,6 +26,11 @@
 
 H, W = 640, 480
 
+FOCAL_PX = 35.
+
+FIELD_OF_VIEW_W_RADIANS = 2 * np.arctan(W / (2 * FOCAL_PX))
+FIELD_OF_VIEW_H_RADIANS = 2 * np.arctan(H / (2 * FOCAL_PX))
+
 
 def make_camera_spec(
     *,
@@ -34,7 +39,7 @@ def make_camera_spec(
 ) -> v3d.PinholeCamera:
   spec = v3d.PinholeCamera.from_focal(
       resolution=(H, W),
-      focal_in_px=35.,
+      focal_in_px=FOCAL_PX,
       xnp=xnp,
   )
   spec = spec.broadcast_to(shape)
@@ -58,6 +63,13 @@ def test_camera_spec_init(
   assert spec.hw == (H, W)
   assert spec.shape == spec_shape
   assert spec.K.shape == spec_shape + (3, 3)
+  assert spec.fw == FOCAL_PX
+  assert spec.fh == FOCAL_PX
+  assert spec.focal_px_wh == (FOCAL_PX, FOCAL_PX)
+  assert spec.focal_px == FOCAL_PX
+  assert spec.fov_w == FIELD_OF_VIEW_W_RADIANS
+  assert spec.fov_h == FIELD_OF_VIEW_H_RADIANS
+  assert spec.fov == (FIELD_OF_VIEW_W_RADIANS, FIELD_OF_VIEW_H_RADIANS)
 
   if xnp is None:
     xnp = np

visu3d/dc_arrays/camera_test.py

@@ -24,8 +24,11 @@
 # Activate the fixture
 set_tnp = enp.testing.set_tnp
 
-
 H, W = 64, 128
+FOCAL_PX = 34.
+
+FIELD_OF_VIEW_W_RADIANS = 2 * np.arctan(W / (2 * FOCAL_PX))
+FIELD_OF_VIEW_H_RADIANS = 2 * np.arctan(H / (2 * FOCAL_PX))
 
 
 def _make_cam(
@@ -34,7 +37,7 @@ def _make_cam(
     shape: v3d.typing.Shape,
 ) -> v3d.Camera:
   """Create a camera at (0, 4, 0) looking at the center."""
-  spec = v3d.PinholeCamera.from_focal(resolution=(H, W), focal_in_px=34.)
+  spec = v3d.PinholeCamera.from_focal(resolution=(H, W), focal_in_px=FOCAL_PX)
   cam = v3d.Camera.from_look_at(
       spec=spec.as_xnp(xnp),
       pos=[0, 4, 0],  # Camera on the `y` axis
@@ -59,6 +62,13 @@ def test_camera_properties(xnp: enp.NpModule, shape: v3d.typing.Shape):
   assert cam.w == W
   assert cam.wh == (W, H)
   assert cam.hw == (H, W)
+  assert cam.spec.fw == FOCAL_PX
+  assert cam.spec.fh == FOCAL_PX
+  assert cam.spec.focal_px_wh == (FOCAL_PX, FOCAL_PX)
+  assert cam.spec.focal_px == FOCAL_PX
+  assert cam.spec.fov_w == FIELD_OF_VIEW_W_RADIANS
+  assert cam.spec.fov_h == FIELD_OF_VIEW_H_RADIANS
+  assert cam.spec.fov == (FIELD_OF_VIEW_W_RADIANS, FIELD_OF_VIEW_H_RADIANS)
 
 
 @enp.testing.parametrize_xnp()