Update distortion parameter return type/order

Author: elliott-imhoff

imgparse/parser.py

@@ -15,6 +15,7 @@
 from imgparse.types import (
     AltitudeSource,
     Dimensions,
+    DistortionParams,
     Euler,
     PixelCoords,
     Version,
@@ -274,11 +275,11 @@ def principal_point(self) -> PixelCoords:
                 "Couldn't find the principal point tag. Sensor might not be supported"
             )
 
-    def distortion_parameters(self) -> list[float]:
+    def distortion_parameters(self) -> DistortionParams:
         """
         Get the radial distortion parameters of the sensor that took the image.
 
-        Returns distortion params in [k1, k2, k3, p1, p2] order.
+        Returns distortion params in [k1, k2, p1, p2, k3] order.
         """
         try:
             if self.make() == "DJI":
@@ -293,11 +294,11 @@ def distortion_parameters(self) -> list[float]:
                     raise ValueError("Expected 9 numeric values after semicolon")
 
                 k1, k2, p1, p2, k3 = values[4:9]
-                return [k1, k2, k3, p1, p2]
+                return DistortionParams(k1, k2, p1, p2, k3)
             elif self.make() == "Sentera":
-                return list(
-                    map(float, str(self.xmp_data[self.xmp_tags.DISTORTION]).split(","))
-                )
+                distortion_data = str(self.xmp_data[self.xmp_tags.DISTORTION])
+                k1, k2, k3, p1, p2 = [float(v) for v in distortion_data.split(",")]
+                return DistortionParams(k1, k2, p1, p2, k3)
             raise ValueError("Sensor isn't supported")
         except (KeyError, ValueError):
             raise ParsingError(

imgparse/types.py

@@ -50,6 +50,16 @@ class Version(NamedTuple):
     patch: int
 
 
+class DistortionParams(NamedTuple):
+    """Distortion parameters in OpenCV order."""
+
+    k1: float
+    k2: float
+    p1: float
+    p2: float
+    k3: float
+
+
 class AltitudeSource(Enum):
     """Altitude source enum."""
 

tests/test_imgparse.py

@@ -356,7 +356,12 @@ def test_get_principal_point_bad(bad_sentera_parser: MetadataParser) -> None:
 
 def test_get_distortion_params_65r(sentera_65r_parser: MetadataParser) -> None:
     params = sentera_65r_parser.distortion_parameters()
-    assert params == [-0.127, 0.126, 0.097, 0.0, 0.0]
+    assert params == (-0.127, 0.126, 0.0, 0.0, 0.097)
+
+
+def test_get_distortion_params_dji(dji_ms_parser: MetadataParser) -> None:
+    params = dji_ms_parser.distortion_parameters()
+    assert params == (-0.412558, 0.3754, -2.47e-05, -2.47e-05, -0.457753)
 
 
 def test_get_distortion_params_bad(bad_sentera_parser: MetadataParser) -> None: