diff --git a/public/js/exhibit.js b/public/js/exhibit.js
index 54a9164..5dbd805 100644
--- a/public/js/exhibit.js
+++ b/public/js/exhibit.js
@@ -34,6 +34,26 @@ let tracking = { markers: 0, lastSeen: 0 };
 const clockOffsetSamples = [];
 let clockOffset = 0; // serverNow - clientNow
 
+// Debug pose readout (dev mode): shows the fused camera orientation so orientation
+// bugs can be diagnosed from numbers instead of eyeballing. Filled each fused frame.
+const _dbgEuler = new THREE.Euler();
+const _dbgV = new THREE.Vector3();
+let dbgEl = null;
+function updateDbg(fusedQuat, markerCount) {
+  if (!dbgEl) return;
+  const deg = r => (r * 180 / Math.PI).toFixed(0).padStart(4);
+  // raw fused (CV-frame) orientation as YXZ euler
+  _dbgEuler.setFromQuaternion(fusedQuat, 'YXZ');
+  const rawLine = `raw  P${deg(_dbgEuler.x)} Y${deg(_dbgEuler.y)} R${deg(_dbgEuler.z)}`;
+  // after correction: camera view (-Z) and up (+Y) in world
+  const view = _dbgV.set(0, 0, -1).applyQuaternion(camera3.quaternion).clone();
+  const up = _dbgV.set(0, 1, 0).applyQuaternion(camera3.quaternion).clone();
+  const v3 = v => `(${v.x.toFixed(2)},${v.y.toFixed(2)},${v.z.toFixed(2)})`;
+  dbgEl.textContent =
+    `markers ${markerCount}\n${rawLine}\nview ${v3(view)}\nup   ${v3(up)}\n` +
+    `pos  ${v3(camera3.position)}`;
+}
+
 async function boot() {
   info = await (await fetch('/api/info')).json();
   installErrorReporter(info.mode === 'dev');
@@ -111,6 +131,9 @@ async function start() {
   detector = createDetector();
   fuser = new WorldFuser();
 
+  // dev-mode pose readout
+  if (info.mode === 'dev') { dbgEl = $('#dbg'); if (dbgEl) dbgEl.style.display = 'block'; }
+
   // network
   const net = new ExhibitNet();
   net.on('scene', (m) => {
@@ -220,6 +243,7 @@ function loop(t) {
         camera3.position.copy(fused.position);
         // convert OpenCV camera frame -> Three.js (OpenGL) camera frame
         camera3.quaternion.copy(fused.quaternion).multiply(CV_TO_GL);
+        updateDbg(fused.quaternion, fused.markerCount);
       }
     }
   }