added new filtration and fixed processing parameters

data_acq_and_processing/processing/data_processor/include/processing_live_config.hpp

@@ -45,8 +45,10 @@ struct ProcessingLiveConfig {
     float gpr_min_depth_m = 2.0F;
     float gpr_max_depth_m = 14.0F;
     float gpr_range_comp_power = 0.1F;
-    float gpr_angle_comp_power = 0.0F;
     float gpr_comp_power = 0.2F;
+    // BP object-detection stop level, as a fraction of the global peak (Python
+    // Horns_motion_3libre.py BP_OBJECT_MIN_FRAC); peaks below it are not objects.
+    float gpr_object_min_frac = 0.7F;
     std::string gpr_score_mode = "combined";
     // Backprojection intra-sweep speed-correction mode: "int_minus" (full
     // correction) or "int_focus" (focusing residual only). Mirrors the Python
@@ -73,13 +75,15 @@ struct ProcessingLiveConfig {
     // BP image is computed in the y=imaging_plane_y_m slice of the 3D grid.
     // Default 0 keeps legacy 1D antenna layouts imaging in the antenna plane.
     float gpr_imaging_plane_y_m = 0.0F;
-    // Locator filter parameters. Mode-dependent threshold (legacy_gpr uses
-    // `legacy_gpr_min_visible_pair_count`, everything else uses
-    // `gpr_min_visible_score`). Draw limits apply only to non-legacy modes.
-    float gpr_min_visible_score = 0.0F;
+    // Coherent BP object visibility (window + the draw limits below) is applied in
+    // the processor itself, matching Horns_motion_3libre.py — there is NO score
+    // threshold for it. Only legacy GPR still thresholds, on a pair count.
     float legacy_gpr_min_visible_pair_count = 0.0F;
     std::uint32_t gpr_max_detected_objects_to_draw = 0;
     std::uint32_t gpr_draw_top_m_objects = 0;
+    // Cross-frame approach filter: an object is shown only once it persists as a
+    // motion-consistent track over this many consecutive frames (<= 1 disables it).
+    std::uint32_t gpr_object_approach_min_frames = 3;
     // Visible X/Z window (metres). The locator clips broadcast objects to this
     // window so the socket emits only what the desktop plot actually shows.
     float gpr_visible_x_min_m = -2.0F;

data_acq_and_processing/processing/data_processor/src/data_processor.cpp

@@ -65,7 +65,7 @@ void DataProcessor::run(const std::atomic<bool>& stop_requested) {
     std::uint64_t last_applied_history_command_seq = 0;
     std::uint64_t error_count = 0;
     std::uint64_t consecutive_errors = 0;
-    // Fix #55: track the socket-fed speed used for the last reprocess so a change
+    // track the socket-fed speed used for the last reprocess so a change
     // arriving without a live-config revision bump still triggers a reprocess of
     // the current result (gated below by reprocess_current_result).
     std::optional<double> last_reprocessed_socket_speed = std::nullopt;
@@ -124,7 +124,7 @@ void DataProcessor::run(const std::atomic<bool>& stop_requested) {
                     publish_locator(replay_result, live_config);
                 }
                 last_replayed_revision = live_revision;
-                // Fix #55: record the speed we just reprocessed with so an
+                //record the speed we just reprocessed with so an
                 // unchanged socket value does not retrigger every iteration.
                 last_reprocessed_socket_speed = current_socket_speed;
             }
@@ -232,29 +232,23 @@ auto DataProcessor::build_locator_filter(const ProcessingLiveConfig& live_config
         live_config.processor_mode.empty() ? default_processor_mode_ : live_config.processor_mode;
 
     radar::locator::FilterParams filter{};
-    // Clip broadcast objects to the same visible X/Z window the desktop plot uses,
-    // so the socket emits only the objects the operator actually sees.
-    filter.visible_bounds = radar::locator::VisibleBounds{
-        .x_min = live_config.gpr_visible_x_min_m,
-        .x_max = live_config.gpr_visible_x_max_m,
-        .z_min = live_config.gpr_visible_z_min_m,
-        .z_max = live_config.gpr_visible_z_max_m,
-    };
     if (requested_mode == "legacy_gpr") {
+        // Legacy GPR emits its objects unfiltered, so the socket applies the legacy
+        // rule here: clip to the visible window and threshold on the pair count. The
+        // GUI disables "draw top N" for legacy, so we skip it on the wire to match.
+        filter.visible_bounds = radar::locator::VisibleBounds{
+            .x_min = live_config.gpr_visible_x_min_m,
+            .x_max = live_config.gpr_visible_x_max_m,
+            .z_min = live_config.gpr_visible_z_min_m,
+            .z_max = live_config.gpr_visible_z_max_m,
+        };
         filter.min_score = live_config.legacy_gpr_min_visible_pair_count;
-        // The GUI deliberately disables the "draw top N" capping for legacy
-        // GPR, so we also skip it on the wire to match observation semantics.
         filter.draw_limits.reset();
-    } else {
-        filter.min_score = live_config.gpr_min_visible_score;
-        if (live_config.gpr_max_detected_objects_to_draw > 0U
-            && live_config.gpr_draw_top_m_objects > 0U) {
-            filter.draw_limits = radar::locator::DrawLimits{
-                .max_detected_objects = live_config.gpr_max_detected_objects_to_draw,
-                .draw_top_objects = live_config.gpr_draw_top_m_objects,
-            };
-        }
     }
+    // Coherent BP already emits the FINAL visible object set from the processor
+    // (window + N/M, no score threshold — matching Horns_motion_3libre.py), so the
+    // socket forwards it verbatim. The default FilterParams passes everything through
+    // (it only drops non-finite rows), keeping the filtering logic in one place.
     return filter;
 }
 

data_acq_and_processing/processing/data_processor/src/processing_live_config.cpp

@@ -255,11 +255,11 @@ void apply_legacy_gpr_algorithm_alias(ProcessingLiveConfig& config, const std::s
         }
         config.gpr_range_comp_power = static_cast<float>(found->get<double>());
     }
-    if (const auto found = root.find("gpr_angle_comp_power"); found != root.end()) {
+    if (const auto found = root.find("gpr_object_min_frac"); found != root.end()) {
         if (!found->is_number()) {
-            throw std::runtime_error("processing.gpr_angle_comp_power must be number");
+            throw std::runtime_error("processing.gpr_object_min_frac must be number");
         }
-        config.gpr_angle_comp_power = static_cast<float>(found->get<double>());
+        config.gpr_object_min_frac = static_cast<float>(found->get<double>());
     }
     if (const auto found = root.find("gpr_comp_power"); found != root.end()) {
         if (!found->is_number()) {
@@ -355,12 +355,6 @@ void apply_legacy_gpr_algorithm_alias(ProcessingLiveConfig& config, const std::s
         }
         config.gpr_imaging_plane_y_m = static_cast<float>(found->get<double>());
     }
-    if (const auto found = root.find("gpr_min_visible_score"); found != root.end()) {
-        if (!found->is_number()) {
-            throw std::runtime_error("processing.gpr_min_visible_score must be number");
-        }
-        config.gpr_min_visible_score = static_cast<float>(found->get<double>());
-    }
     for (const auto& [key, target] : {
              std::pair{"gpr_visible_x_min_m", &config.gpr_visible_x_min_m},
              std::pair{"gpr_visible_x_max_m", &config.gpr_visible_x_max_m},
@@ -388,6 +382,10 @@ void apply_legacy_gpr_algorithm_alias(ProcessingLiveConfig& config, const std::s
         config.gpr_draw_top_m_objects =
             parse_u32_number(*found, "processing.gpr_draw_top_m_objects");
     }
+    if (const auto found = root.find("gpr_object_approach_min_frames"); found != root.end()) {
+        config.gpr_object_approach_min_frames =
+            parse_u32_number(*found, "processing.gpr_object_approach_min_frames");
+    }
     if (const auto found = root.find("ignore_socket_speed"); found != root.end()) {
         if (!found->is_boolean()) {
             throw std::runtime_error("processing.ignore_socket_speed must be bool");

data_acq_and_processing/processing/processors/include/gpr_processor.hpp

@@ -1,5 +1,6 @@
 #pragma once
 
+#include "object_approach_filter.hpp"
 #include "processor_interface.hpp"
 
 namespace radar::processing {
@@ -13,6 +14,11 @@ class GprProcessor final : public ProcessorInterface {
         std::span<const ipc::PreprocessedCollection> previous_collections,
         const ProcessingLiveConfig& live_config
     ) -> ipc::ResultCollection override;
+
+  private:
+    // Cross-frame "approach" track filter. Persists across collections because the
+    // owning processor instance is long-lived (one per data_processor run).
+    ObjectApproachFilter approach_filter_{};
 };
 
 class LegacyGprProcessor final : public ProcessorInterface {

data_acq_and_processing/processing/processors/include/object_approach_filter.hpp

@@ -0,0 +1,172 @@
+#pragma once
+
+#include <algorithm>
+#include <cmath>
+#include <cstddef>
+#include <cstdint>
+#include <deque>
+#include <limits>
+#include <vector>
+
+namespace radar::processing {
+
+// Temporal "approach" filter for coherent-BP detections — a port of the objects-only
+// filter in Horns_motion_3libre's demonstrate notebook.
+//
+// It keeps only objects that persist as a *motion-consistent track* across at least
+// `min_frames` consecutive frames: as the radar moves, a real target reappears at a
+// predictable, shifting (x, z), whereas a one-frame noise spike forms no track and is
+// dropped. The expected per-frame change in range is `speed * dt * cos(look_angle)`,
+// where `dt` is the real interval between consecutive frames (so dropped frames and a
+// varying frame period are handled naturally).
+//
+// CAUSAL: unlike the offline notebook (which can look forward over the whole sequence),
+// this confirms a track by looking *backward* — an object is kept once it ends a track
+// of `min_frames` frames seen so far. A target therefore first appears after it has
+// persisted `min_frames` frames; the early frames of its track are not shown
+// retroactively.
+//
+// Stateless across pipeline restarts is approximated by breaking tracks across a large
+// inter-frame gap (`kMaxFrameGapSeconds`), so a stale history from a previous run cannot
+// spuriously confirm objects.
+//
+// IDEMPOTENT under reprocessing: the data_processor re-runs the last collection (or
+// replays the whole window) whenever live settings or the socket speed change, with no
+// new sweep. The history is therefore keyed by `frame_id` (the strictly increasing
+// collection id): the same id replaces its entry (reprocess of the current frame), a
+// smaller id rebuilds from scratch (a replay restart), so repeated reprocessing never
+// duplicates frames or falsely confirms a track.
+class ObjectApproachFilter {
+  public:
+    struct Point {
+        double x_m;
+        double z_m;
+    };
+
+    // Record `objects` as frame `frame_id` and return, per object, whether it is
+    // confirmed (ends a >= `min_frames` motion-consistent track). `frame_id` is the
+    // collection id (identity/order, survives reprocessing); `frame_time_seconds` is the
+    // frame's wall-clock timestamp (drives the inter-frame interval); `speed_m_s`/
+    // `look_angle_deg` are the live motion estimate. `min_frames <= 1` disables filtering.
+    [[nodiscard]] auto confirm(
+        const std::vector<Point>& objects,
+        std::uint64_t frame_id,
+        double frame_time_seconds,
+        double speed_m_s,
+        double look_angle_deg,
+        std::size_t min_frames
+    ) -> std::vector<bool> {
+        record_frame(Frame{frame_id, frame_time_seconds, objects});
+        const std::size_t history_depth = std::max<std::size_t>(min_frames, 1U);
+        while (history_.size() > history_depth) {
+            history_.pop_front();
+        }
+
+        std::vector<bool> confirmed(objects.size(), min_frames <= 1U);
+        if (min_frames <= 1U || history_.size() < min_frames) {
+            return confirmed;  // disabled, or not enough history yet to confirm anything
+        }
+
+        const double range_step_per_second = std::abs(speed_m_s) * std::cos(to_radians(look_angle_deg));
+        for (std::size_t object_index = 0U; object_index < objects.size(); ++object_index) {
+            confirmed[object_index] = has_backward_track(objects[object_index], min_frames, range_step_per_second);
+        }
+        return confirmed;
+    }
+
+    void reset() { history_.clear(); }
+
+  private:
+    struct Frame {
+        std::uint64_t id;
+        double time_seconds;
+        std::vector<Point> objects;
+    };
+
+    // Append a genuinely new frame, replace the current one on reprocessing (same id),
+    // or rebuild from scratch when the id steps backward (a replay restart). This keeps
+    // the history one entry per distinct collection no matter how often settings change.
+    void record_frame(Frame frame) {
+        if (history_.empty() || frame.id > history_.back().id) {
+            history_.push_back(std::move(frame));
+        } else if (frame.id == history_.back().id) {
+            history_.back() = std::move(frame);
+        } else {
+            history_.clear();
+            history_.push_back(std::move(frame));
+        }
+    }
+
+    // Fixed matching tolerances (Horns_motion notebook 0.2 block). Range decreases as the
+    // radar approaches the target, hence the negative Z sign.
+    static constexpr double kXToleranceM = 0.45;
+    static constexpr double kRangeToleranceFraction = 0.85;
+    static constexpr double kRangeToleranceFloorM = 0.12;
+    static constexpr double kRangeSign = -1.0;
+    static constexpr double kMaxFrameGapSeconds = 2.0;
+
+    [[nodiscard]] static auto to_radians(double degrees) -> double {
+        return degrees * (M_PI / 180.0);
+    }
+
+    // Walk back from the current object through the history, matching a motion-consistent
+    // predecessor in each earlier frame. Confirmed iff a full chain of `min_frames` frames
+    // (the current one plus `min_frames - 1` predecessors) is found.
+    [[nodiscard]] auto has_backward_track(
+        const Point& object,
+        std::size_t min_frames,
+        double range_step_per_second
+    ) const -> bool {
+        const std::size_t newest = history_.size() - 1U;
+        Point current = object;
+        for (std::size_t step = 1U; step < min_frames; ++step) {
+            const std::size_t earlier_index = newest - step;
+            const Frame& earlier = history_[earlier_index];
+            const double dt = history_[earlier_index + 1U].time_seconds - earlier.time_seconds;
+            if (!(dt > 0.0) || dt > kMaxFrameGapSeconds) {
+                return false;  // non-monotonic time, or a gap that breaks the track
+            }
+            const double expected_range_shift = range_step_per_second * dt;
+            const Point* predecessor = match_predecessor(current, earlier.objects, expected_range_shift);
+            if (predecessor == nullptr) {
+                return false;
+            }
+            current = *predecessor;
+        }
+        return true;
+    }
+
+    // The best earlier-frame object consistent with `object` having moved by one frame:
+    // its range was larger by `expected_range_shift` (radar since approached), within the
+    // cross-range and range tolerances. Returns nullptr when nothing matches.
+    [[nodiscard]] static auto match_predecessor(
+        const Point& object,
+        const std::vector<Point>& candidates,
+        double expected_range_shift
+    ) -> const Point* {
+        const double target_z = object.z_m - (kRangeSign * expected_range_shift);
+        const double range_tolerance =
+            std::max(kRangeToleranceFloorM, kRangeToleranceFraction * expected_range_shift);
+
+        const Point* best = nullptr;
+        double best_cost = std::numeric_limits<double>::infinity();
+        for (const Point& candidate : candidates) {
+            const double dx = std::abs(candidate.x_m - object.x_m);
+            const double dz = std::abs(candidate.z_m - target_z);
+            if (dx > kXToleranceM || dz > range_tolerance) {
+                continue;
+            }
+            const double cost = (dx / kXToleranceM) * (dx / kXToleranceM)
+                + (dz / range_tolerance) * (dz / range_tolerance);
+            if (cost < best_cost) {
+                best = &candidate;
+                best_cost = cost;
+            }
+        }
+        return best;
+    }
+
+    std::deque<Frame> history_{};  // recent frames, newest at the back; capped to min_frames
+};
+
+}  // namespace radar::processing

data_acq_and_processing/processing/processors/src/gpr_backprojection_processor.ipp

@@ -21,7 +21,6 @@ constexpr double kSmoothSigma = 1.5;
 // same default 'reflect' (half-sample symmetric) extension — see reflect_index.
 constexpr double kGaussianTruncate = 4.0;
 constexpr std::size_t kMaxObjects = 10U;
-constexpr double kObjectMinFrac = 0.7;
 constexpr double kRegionThresholdFrac = 0.75;
 constexpr double kSuppressThresholdFrac = 0.20;
 constexpr double kSuppressRadiusXM = 0.80;
@@ -1405,7 +1404,8 @@ void apply_depth_gate(
 
 [[nodiscard]] auto find_bp_objects(
     const std::vector<double>& bp_image,
-    const GridDefinition& grid
+    const GridDefinition& grid,
+    double min_frac
 ) -> std::vector<ObjectRecord> {
     std::vector<ObjectRecord> objects{};
     if (bp_image.empty() || grid.x_grid.size() < 2U || grid.z_grid.size() < 2U) {
@@ -1414,7 +1414,7 @@ void apply_depth_gate(
 
     std::vector<double> work = bp_image;
     const double global_peak = max_value(work);
-    const double stop_level = kObjectMinFrac * global_peak;
+    const double stop_level = min_frac * global_peak;
     if (!(global_peak > 0.0)) {
         return objects;
     }
@@ -1740,7 +1740,15 @@ void add_bp_score_metrics(
     }
 }
 
-[[nodiscard]] auto output_objects_sorted(
+// Select the FINAL visible objects exactly as Horns_motion_3libre.py does, so the
+// processor is the single source of truth: the GUI plot and the locator socket both
+// consume this set verbatim (no second, duplicated filter). Steps, in order:
+//   1. drop sidelobe candidates (when enabled), then sort by score (peak tie-break);
+//   2. clip to the visible X/Z window (display window doubles as an object gate);
+//   3. apply the N/M draw rule (BP_MAX_DETECTED_OBJECTS_TO_DRAW / BP_DRAW_TOP_M_OBJECTS):
+//      if more than N survive, show none; otherwise keep the top M.
+// There is deliberately NO score threshold (the Python reference has none).
+[[nodiscard]] auto select_visible_objects(
     const std::vector<ObjectRecord>& objects,
     const ProcessingLiveConfig& live_config
 ) -> std::vector<const ObjectRecord*> {
@@ -1750,6 +1758,12 @@ void add_bp_score_metrics(
         if (live_config.gpr_remove_sidelobe_objects_enabled && object.sidelobe_candidate) {
             continue;
         }
+        if (object.x_m < live_config.gpr_visible_x_min_m
+            || object.x_m > live_config.gpr_visible_x_max_m
+            || object.z_m < live_config.gpr_visible_z_min_m
+            || object.z_m > live_config.gpr_visible_z_max_m) {
+            continue;
+        }
         visible.push_back(&object);
     }
 
@@ -1759,6 +1773,17 @@ void add_bp_score_metrics(
         }
         return left->selected_score > right->selected_score;
     });
+
+    // N/M draw rule (0 on either disables limiting, mirroring the GUI/locator default).
+    const auto max_detected = live_config.gpr_max_detected_objects_to_draw;
+    const auto draw_top = live_config.gpr_draw_top_m_objects;
+    if (max_detected > 0U && draw_top > 0U) {
+        if (visible.size() > max_detected) {
+            visible.clear();
+        } else if (visible.size() > draw_top) {
+            visible.resize(draw_top);
+        }
+    }
     return visible;
 }
 
@@ -1815,7 +1840,8 @@ void add_bp_score_metrics(
     const config::RunConfig& run_config,
     const ipc::PreprocessedCollection& collection,
     std::span<const ipc::PreprocessedCollection> previous_collections,
-    const ProcessingLiveConfig& live_config
+    const ProcessingLiveConfig& live_config,
+    ObjectApproachFilter& approach_filter
 ) -> ipc::ResultCollection {
     ipc::ResultCollection results{};
     results.collection_id = collection.collection_id;
@@ -1833,8 +1859,10 @@ void add_bp_score_metrics(
         return results;
     }
 
-    const double velocity_mps =
-        kSpeedOfLightMetersPerSec / std::sqrt(std::max(1e-6, static_cast<double>(run_config.gpr.relative_permittivity)));
+    // Coherent BP fixes the medium to vacuum/air (eps_r = 1), matching the Python
+    // reference Horns_motion_3libre.py (its 0.3 block hardcodes eps_r = 1.0). The
+    // configurable relative_permittivity stays a legacy-GPR-only knob.
+    const double velocity_mps = kSpeedOfLightMetersPerSec;
     const double start_hz = static_cast<double>(live_config.gpr_start_freq_mhz) * 1'000'000.0;
     const double stop_hz = static_cast<double>(live_config.gpr_stop_freq_mhz) * 1'000'000.0;
     const double min_depth_m = static_cast<double>(live_config.gpr_min_depth_m);
@@ -1920,7 +1948,7 @@ void add_bp_score_metrics(
         min_depth_m,
         max_depth_m,
         std::max(0.0, static_cast<double>(live_config.gpr_range_comp_power)),
-        std::max(0.0, static_cast<double>(live_config.gpr_angle_comp_power))
+        0.0  // angle compensation fixed off (Python Horns_motion_3libre.py COMP_ANGLE_POWER = 0.0)
     );
     if (bp.image.empty()) {
         return results;
@@ -1930,7 +1958,7 @@ void add_bp_score_metrics(
     const auto incoherent_display_map =
         normalize_bp_map(bp.incoherent, grid, min_depth_m, max_depth_m, kSmoothSigma);
 
-    auto objects = find_bp_objects(display_map, grid);
+    auto objects = find_bp_objects(display_map, grid, static_cast<double>(live_config.gpr_object_min_frac));
     add_local_prominence_metrics(objects, display_map, grid, min_depth_m, max_depth_m);
     add_incoherent_support_metrics(objects, incoherent_display_map, bp.coherence_factor);
     mark_sidelobe_candidates(objects, selected_traces, selection, imaging_plane_y_m);
@@ -1951,14 +1979,34 @@ void add_bp_score_metrics(
 
     results.collection_payloads.push_back(build_image_payload("gpr_accumulator", grid.x_grid, grid.z_grid, display_map));
 
+    // Final visible set (window + N/M), then the cross-frame approach filter: keep only
+    // objects confirmed as a >= min_frames motion-consistent track (Horns_motion notebook).
+    const auto visible = select_visible_objects(objects, live_config);
+    std::vector<ObjectApproachFilter::Point> visible_points{};
+    visible_points.reserve(visible.size());
+    for (const auto* object : visible) {
+        visible_points.push_back({object->x_m, object->z_m});
+    }
+    const auto confirmed = approach_filter.confirm(
+        visible_points,
+        collection.collection_id,
+        static_cast<double>(collection.monotonic_ns) * 1e-9,
+        static_cast<double>(live_config.gpr_speed_m_s),
+        static_cast<double>(live_config.gpr_look_angle_deg),
+        static_cast<std::size_t>(live_config.gpr_object_approach_min_frames)
+    );
+
     std::vector<std::vector<float>> point_rows{};
-    point_rows.reserve(objects.size());
-    for (const auto* object : output_objects_sorted(objects, live_config)) {
+    point_rows.reserve(visible.size());
+    for (std::size_t index = 0U; index < visible.size(); ++index) {
+        if (!confirmed[index]) {
+            continue;
+        }
         point_rows.push_back(
             {
-                static_cast<float>(object->x_m),
-                static_cast<float>(object->z_m),
-                static_cast<float>(object->selected_score),
+                static_cast<float>(visible[index]->x_m),
+                static_cast<float>(visible[index]->z_m),
+                static_cast<float>(visible[index]->selected_score),
             }
         );
     }

data_acq_and_processing/processing/processors/src/gpr_processor.cpp

@@ -36,7 +36,7 @@ auto GprProcessor::process_collection(
     std::span<const ipc::PreprocessedCollection> previous_collections,
     const ProcessingLiveConfig& live_config
 ) -> ipc::ResultCollection {
-    return process_backprojection_gpr(run_config, collection, previous_collections, live_config);
+    return process_backprojection_gpr(run_config, collection, previous_collections, live_config, approach_filter_);
 }
 
 auto LegacyGprProcessor::name() const -> std::string {