Fix ALPR Batch and memory leak

modules/ANSLPR/ANSLPR.cpp

@@ -304,11 +304,18 @@ namespace ANSCENTER {
 				p.framesSinceLastSeen++;
 			}
 
-			// Periodic pruning: remove stale entries
-			static thread_local int pruneCounterById = 0;
-			pruneCounterById++;
-			if (pruneCounterById >= 30 && plates.size() > 20) {
-				pruneCounterById = 0;
+			// Periodic pruning: remove stale entries.
+			// NOTE: previously used `static thread_local int pruneCounterById`.
+			// LabVIEW dispatches calls across a worker-thread pool, so the
+			// thread-local counter fragmented across threads and pruning
+			// effectively stopped firing — `trackedPlatesById[cameraId]` then
+			// grew unbounded (one entry per frame when trackIds never repeat),
+			// which manifested as a slow LabVIEW-side memory leak. The counter
+			// is now a plain instance member guarded by `_mutex` (taken above),
+			// so every 30th call across the whole engine triggers a prune pass.
+			_pruneCounterById++;
+			if (_pruneCounterById >= 30 && plates.size() > 20) {
+				_pruneCounterById = 0;
 				int staleThreshold = maxFrames * 3;
 				for (auto it = plates.begin(); it != plates.end(); ) {
 					if (it->second.framesSinceLastSeen > staleThreshold) {
@@ -521,6 +528,36 @@ namespace ANSCENTER {
 	ANSALPR::~ANSALPR(){};
 	bool ANSALPR::Destroy() { return true; };
 
+	// Default batch implementation — fallback that loops RunInference over
+	// vehicle crops one at a time. Subclasses should override this with a
+	// true batched path (see ANSALPR_OD::RunInferencesBatch and
+	// ANSALPR_OCR::RunInferencesBatch) to issue a single LP-detect and a
+	// single OCR call per frame instead of N. The fallback preserves the
+	// "transform bboxes back to frame coordinates" contract so a subclass
+	// that never overrides still produces valid output.
+	std::vector<Object> ANSALPR::RunInferencesBatch(
+		const cv::Mat& input,
+		const std::vector<cv::Rect>& vehicleBoxes,
+		const std::string& cameraId)
+	{
+		std::vector<Object> out;
+		if (input.empty() || vehicleBoxes.empty()) return out;
+		const cv::Rect frameRect(0, 0, input.cols, input.rows);
+		out.reserve(vehicleBoxes.size());
+		for (const auto& r : vehicleBoxes) {
+			cv::Rect c = r & frameRect;
+			if (c.width <= 0 || c.height <= 0) continue;
+			const cv::Mat crop = input(c);
+			std::vector<Object> perVehicle = RunInference(crop, cameraId);
+			for (auto& obj : perVehicle) {
+				obj.box.x += c.x;
+				obj.box.y += c.y;
+				out.push_back(std::move(obj));
+			}
+		}
+		return out;
+	}
+
 	std::vector<cv::Rect> ANSCENTER::ANSALPR::GetBoundingBoxes(const std::string& strBBoxes) {
 		std::vector<cv::Rect> bBoxes;
 		bBoxes.clear();