simulate confidence for object detection and populate classId and computed confidence level in Java (while building the PhotonTrackedTarget)

Author: shdalton

photon-lib/py/photonlibpy/simulation/photonCameraSim.py

@@ -368,6 +368,15 @@ def distance(target: VisionTargetSim):
                     noisyTargetCorners,
                 )
 
+            # Compute object detection confidence if this is an obj det target
+            classId = tgt.objDetClassId
+            conf = tgt.objDetConf
+            if classId >= 0 and conf < 0:
+                # Simulate confidence using sqrt-scaled area for a more realistic
+                # curve. Raw areaPercent/100 is tiny for most targets; sqrt scaling
+                # gives reasonable values even for small-but-visible objects.
+                conf = max(0.0, min(1.0, math.sqrt(areaPercent / 100.0) * 2.0))
+
             smallVec: list[TargetCorner] = []
             for corner in minAreaRectPts:
                 smallVec.append(TargetCorner(corner[0], corner[1]))
@@ -381,6 +390,8 @@ def distance(target: VisionTargetSim):
                     area=areaPercent,
                     skew=math.degrees(centerRot.X()),
                     fiducialId=tgt.fiducialId,
+                    objDetectId=classId,
+                    objDetectConf=conf,
                     detectedCorners=cornersFloat,
                     minAreaRectCorners=smallVec,
                     bestCameraToTarget=pnpSim.best if pnpSim else Transform3d(),

photon-lib/src/main/java/org/photonvision/simulation/PhotonCameraSim.java

@@ -525,15 +525,25 @@ public PhotonPipelineResult process(
                                 .get();
             }
 
+            // Compute object detection confidence if this is an obj det target
+            int classId = tgt.objDetClassId;
+            float conf = tgt.objDetConf;
+            if (classId >= 0 && conf < 0) {
+                // Simulate confidence using sqrt-scaled area for a more realistic
+                // curve. Raw areaPercent/100 is tiny for most targets; sqrt scaling
+                // gives reasonable values even for small-but-visible objects.
+                conf = (float) Math.max(0.0, Math.min(1.0, Math.sqrt(areaPercent / 100.0) * 2.0));
+            }
+
             detectableTgts.add(
                     new PhotonTrackedTarget(
                             -Math.toDegrees(centerRot.getZ()),
                             -Math.toDegrees(centerRot.getY()),
                             areaPercent,
                             Math.toDegrees(centerRot.getX()),
                             tgt.fiducialID,
-                            -1,
-                            -1,
+                            classId,
+                            conf,
                             pnpSim.best,
                             pnpSim.alt,
                             pnpSim.ambiguity,

photon-lib/src/main/java/org/photonvision/simulation/VisionTargetSim.java

@@ -36,6 +36,12 @@ public class VisionTargetSim {
 
     public final int fiducialID;
 
+    /** The object detection class ID, or -1 if not applicable. */
+    public int objDetClassId = -1;
+
+    /** The object detection confidence, or -1 if not applicable. */
+    public float objDetConf = -1;
+
     /**
      * Describes a vision target located somewhere on the field that your vision system can detect.
      *

photon-lib/src/main/native/cpp/photon/simulation/PhotonCameraSim.cpp

@@ -220,6 +220,17 @@ PhotonPipelineResult PhotonCameraSim::Process(
           tgt.GetModel().GetVertices(), noisyTargetCorners);
     }
 
+    // Compute object detection confidence if this is an obj det target
+    int classId = tgt.objDetClassId;
+    float conf = tgt.objDetConf;
+    if (classId >= 0 && conf < 0) {
+      // Simulate confidence using sqrt-scaled area for a more realistic
+      // curve. Raw areaPercent/100 is tiny for most targets; sqrt scaling
+      // gives reasonable values even for small-but-visible objects.
+      conf = static_cast<float>(
+          std::clamp(std::sqrt(areaPercent / 100.0) * 2.0, 0.0, 1.0));
+    }
+
     std::vector<std::pair<float, float>> tempCorners =
         OpenCVHelp::PointsToCorners(minAreaRectPts);
     std::vector<TargetCorner> smallVec;
@@ -237,7 +248,7 @@ PhotonPipelineResult PhotonCameraSim::Process(
         -centerRot.Z().convert<units::degrees>().to<double>(),
         -centerRot.Y().convert<units::degrees>().to<double>(), areaPercent,
         centerRot.X().convert<units::degrees>().to<double>(), tgt.fiducialId,
-        tgt.objDetClassId, tgt.objDetConf,
+        classId, conf,
         pnpSim ? pnpSim->best : frc::Transform3d{},
         pnpSim ? pnpSim->alt : frc::Transform3d{},
         pnpSim ? pnpSim->ambiguity : -1, smallVec, cornersDouble);