Expand technical review with literature methodology and full architecture
Browse files
docs/OrbitSight_Full_Technical_Proposal_Review.md
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@@ -93,6 +93,86 @@ recall, F1, and AP/mAP at IoU 0.5. The competition additionally calls for end-to
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below 40 ms on an Intel Core i9-12900H CPU. There is no track-ID column, so tracking matters
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only when it improves the emitted detection stream.
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## 2. Development history at a glance
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The following table separates comparable leakage-free results from historical development
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`5f176b9baffc3478b1aaada13277e2c6093ba02439b76b8330cb8d654f5f554d`
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-
## 10.
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-
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| Component | Heavy V5/V7 branch | CPU student |
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|---|---:|---:|
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| Input | 3×640×640 | 3×640×640 |
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| Backbone widths | 32, 64, 128, 256 | 4, 8, 16, 32 |
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| Parameters | 8,588,339 | 135,111 |
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| Runtime role | Training teacher | Deployed CPU model |
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The
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That is the correct trade for tiny targets: channel width costs computation, while spatial
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resolution protects localization.
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###
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3. **Stages 2–4:** spatial resolution decreases while channels and context grow. Dilations
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allow later stages to see wider neighborhoods without a large kernel.
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4. **Feature pyramid:** features at different scales are passed to the detector so a tiny,
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medium, or bright elongated response can be localized at an appropriate level.
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5. **Anchor-free head:** each grid location predicts objectness, center offset, width, and
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height. The student is single-class: the question is RSO versus background.
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6. **NMS and top-one ranking:** overlapping proposals are suppressed and the best remaining
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proposal is sent to tracking.
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-
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inference. The quality head and sensor-conditioning branch are disabled. Keeping unused
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training-only work out of inference protects the latency budget.
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-
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-
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that appears consistently over consecutive windows. Removing recurrence would save compute,
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but it would discard the most direct answer to signal starvation.
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The detector proposes appearance-based boxes. The tracker imposes short-horizon physical
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consistency. Each track maintains:
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motion was slow enough that consecutive boxes overlap. IoU association was therefore more
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reliable than a complex motion-only discriminator.
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##
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Before the final no-retrain adjustments, the distilled checkpoint produced:
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the steady-state p95 objective locally, but scheduling outliers still existed in the longer
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profile.
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##
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With the checkpoint and architecture frozen, only low-cost constants were screened:
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The gains are modest but consistent across both aggregate views. No weight, layer, or tensor
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shape changed.
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##
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| Recording | Sensor | F1 | AP | Precision | Recall | Main interpretation |
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|---|---|---:|---:|---:|---:|---|
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##
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The final Linux/amd64 image is designed to be inspected and run without network access. It
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contains:
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mount contract, output schema, model hash, runtime dependencies, calibration constants,
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tracker settings, and baked model-structure text.
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##
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Three different claims must not be confused:
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have still been used for diagnostics. “Leakage-free” here means free of that known training-
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session contamination, not untouched by all development decisions.
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##
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The heavy hybrid has the best local accuracy but fails the CPU requirement by an order of
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magnitude. V5 has a cleaner scientific history but its corrected full-tail latency exceeded
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This is a practical systems decision rather than a claim that the student is universally
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more accurate than every predecessor.
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##
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If new recordings become available, the next work should be data-centered rather than another
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threshold sweep:
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- measure container startup, file reading, formatting, workbook creation, and disk output on
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the organizer's exact i9-12900H hardware.
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##
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OrbitSight progressed from an honest sub-0.1 baseline to a complete real-time CPU system by
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treating data contracts, localization, temporal reasoning, deployment, and evaluation as one
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## Selected references
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1.
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European Conference on Space Debris, 2025.
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Event Cameras,” CVPR, 2023.
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## Primary local evidence
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below 40 ms on an Intel Core i9-12900H CPU. There is no track-ID column, so tracking matters
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only when it improves the emitted detection stream.
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+
## Literature review and design lineage
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+
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OrbitSight is an application-specific synthesis rather than a direct reproduction of one published
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network. Its design draws on neuromorphic sensing, recurrent event detection, anchor-free dense
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detection, model compression, and detection-assisted tracking.
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### Event cameras and space situational awareness
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Gallego et al. formalize the event-camera model: a pixel reports a change in log intensity rather
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than an absolute image sample. The literature emphasizes microsecond timing, high dynamic range,
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low motion blur, and sparse output, while warning that frame algorithms require an event
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representation or event-native computation. OrbitSight preserves polarity and within-window timing,
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but packs events into 40 ms tensors so convolutional and recurrent operations run efficiently on a
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CPU. [Gallego et al., *Event-based Vision: A Survey*, TPAMI 2020](https://doi.org/10.1109/TPAMI.2020.3008413).
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Afshar et al. demonstrated event-based RSO detection and tracking across sensors and observing sites.
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Ralph et al. subsequently studied astrometric calibration and source characterization for event-based
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space imaging. These works motivate OrbitSight's explicit sensor profiles, native-coordinate
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reconstruction, and treatment of preprocessing and coordinate mapping as part of the model contract.
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[Afshar et al., *Event-based Object Detection and Tracking for Space Situational Awareness*,
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2019](https://arxiv.org/abs/1911.08730); [Ralph et al., *Astrometric Calibration and Source
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Characterisation of Neuromorphic Event-based Cameras for Space Imaging*,
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2022](https://arxiv.org/abs/2211.09939).
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### Recurrent event-based object detection
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Perot et al.'s Recurrent Event-camera Detector showed that direct event representations combined with
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recurrent memory outperform feed-forward event detectors because state integrates evidence through
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time. RVT later showed that multi-stage recurrent backbones can obtain a favorable latency/accuracy
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tradeoff. OrbitSight adopts direct event tensors, multi-scale features, and persistent temporal state,
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but uses narrow convolutions and ConvLSTM instead of a transformer for an offline CPU target and tiny
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objects. [Perot et al., *Learning to Detect Objects with a 1 Megapixel Event Camera*, NeurIPS
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2020](https://proceedings.neurips.cc/paper/2020/hash/c213877427b46fa96cff6c39e837ccee-Abstract.html);
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[Gehrig and Scaramuzza, *Recurrent Vision Transformers for Object Detection With Event Cameras*,
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CVPR 2023](https://openaccess.thecvf.com/content/CVPR2023/html/Gehrig_Recurrent_Vision_Transformers_for_Object_Detection_With_Event_Cameras_CVPR_2023_paper.html).
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+
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ConvLSTM replaces fully connected state transitions with spatial convolutions, retaining *where* weak
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evidence occurred. OrbitSight places one after every downsampling stage and uses dilations 1, 2, 4,
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and 8 to enlarge spatial context without changing tensor shapes. [Shi et al., *Convolutional LSTM
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Network*, NeurIPS 2015](https://proceedings.neurips.cc/paper/2015/hash/07563a3fe3bbe7e3ba84431ad9d055af-Abstract.html).
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### Anchor-free detection, imbalance, and localization
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+
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FCOS established fully convolutional anchor-free prediction; YOLOX paired anchor-free boxes with a
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decoupled head. OrbitSight adopts those ideas with custom assignment and scoring for one RSO class.
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It predicts raw center offsets and log sizes on three scales without an anchor bank. [Tian et al.,
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*FCOS*, ICCV 2019](https://openaccess.thecvf.com/content_ICCV_2019/html/Tian_FCOS_Fully_Convolutional_One-Stage_Object_Detection_ICCV_2019_paper.html);
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[Ge et al., *YOLOX*, 2021](https://arxiv.org/abs/2107.08430).
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+
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Dense event tensors create tens of thousands of background cells for at most one target. Focal loss
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suppresses easy negatives so hard examples control learning. OrbitSight uses sigmoid focal BCE for
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objectness. CIoU combines overlap, center distance, and aspect-ratio consistency, aligning training
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more closely with the IoU≥0.5 metric than independent coordinate L1. [Lin et al., *Focal Loss for
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Dense Object Detection*, ICCV 2017](https://openaccess.thecvf.com/content_ICCV_2017/papers/Lin_Focal_Loss_for_ICCV_2017_paper.pdf);
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[Zheng et al., *Distance-IoU Loss*, AAAI 2020](https://ojs.aaai.org/index.php/AAAI/article/view/6999).
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### Distillation and tracking
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Knowledge distillation transfers useful behavior from an expensive model or ensemble into a smaller
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deployable network. OrbitSight follows that deployment logic but does not blindly copy teacher output:
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human boxes remain authoritative, matched teacher boxes provide low-weight targets, and proposals in
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human-empty windows become negative evidence. [Hinton, Vinyals, and Dean, *Distilling the Knowledge
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in a Neural Network*, 2015](https://arxiv.org/abs/1503.02531).
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+
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ByteTrack showed the value of associating lower-confidence detections. OrbitSight evaluated that
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two-tier idea, but production emits only stable global top-one at 0.10, making the nominal low tier
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unreachable. The final system is therefore a single-tier constant-velocity Kalman/coast tracker using
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the same association machinery. [Zhang et al., *ByteTrack*, ECCV
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2022](https://www.ecva.net/papers/eccv_2022/papers_ECCV/papers/136820001.pdf).
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### OrbitSight's design contribution
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- a polarity/recency representation with sensor-specific event denoising;
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- a full-resolution but ultra-narrow recurrent detector;
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- single-class objectness decoding without a redundant class multiplier;
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- selective, human-authoritative distillation from a sensor-routed teacher;
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- weights bound to preprocessing and coordinate-mapping fingerprints;
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- exact stable top-one decoding that avoids NMS without changing the selected box;
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- one evaluated detector/tracker/writer deployment contract.
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+
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## 2. Development history at a glance
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The following table separates comparable leakage-free results from historical development
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|
| 487 |
`5f176b9baffc3478b1aaada13277e2c6093ba02439b76b8330cb8d654f5f554d`
|
| 488 |
|
| 489 |
+
## 10. Final-model methodology
|
| 490 |
+
|
| 491 |
+
This section describes how the final student was produced and evaluated. Section 11 then defines
|
| 492 |
+
the frozen network and inference path component by component.
|
| 493 |
+
|
| 494 |
+
### 10.1 Research questions and temporal unit
|
| 495 |
+
|
| 496 |
+
Development asked whether one model could localize tiny RSOs across all three sensor families,
|
| 497 |
+
inherit useful sensor-specific behavior from the heavy hybrid, and keep the complete deployed path
|
| 498 |
+
below 40 ms. The atomic example is a half-open 40,000 µs event interval. Window phase is anchored to
|
| 499 |
+
the sequence timestamp contract. Recurrent, BA, and tracker state are initialized at the start of a
|
| 500 |
+
sequence, advanced exactly once per window, and destroyed at the boundary.
|
| 501 |
+
|
| 502 |
+
Training uses ordered segments, not shuffled independent frames. Final distillation used 20 consecutive
|
| 503 |
+
windows per segment—0.8 seconds of temporal context—and batches of 16 independent segments. Each batch
|
| 504 |
+
member carries its own four hidden/cell state pairs before truncated backpropagation detaches them.
|
| 505 |
+
|
| 506 |
+
### 10.2 Data preparation
|
| 507 |
+
|
| 508 |
+
For every window the method:
|
| 509 |
+
|
| 510 |
+
1. memory-maps and timestamp-slices events;
|
| 511 |
+
2. applies the sensor-specific neighborhood/time BA rule;
|
| 512 |
+
3. builds positive-count, negative-count, and latest-event-recency planes;
|
| 513 |
+
4. area-resizes the planes to 640×640;
|
| 514 |
+
5. maps human boxes with the same pixel-center convention;
|
| 515 |
+
6. builds the optional per-event auxiliary target.
|
| 516 |
|
| 517 |
+
Counts remain raw. Stateful BA, sensor FiLM, hot-pixel changes, and target-event thinning are disabled
|
| 518 |
+
in the final route. Cache fingerprints bind the source, sensor profile, 40 ms phase, input size, count
|
| 519 |
+
transform, area resize, and coordinate mapping. This prevents a shape-compatible checkpoint from being
|
| 520 |
+
used with semantically different preprocessing, the failure that invalidated V6.
|
| 521 |
+
|
| 522 |
+
### 10.3 Human-authoritative teacher evidence
|
| 523 |
+
|
| 524 |
+
The V5/V7 router runs offline. Its pre-tracker proposals are stored in sidecars aligned one-to-one with
|
| 525 |
+
student windows and marked as matched or unmatched against human GT. Post-tracker teacher boxes are
|
| 526 |
+
diagnostic only. The selective objective is:
|
| 527 |
+
|
| 528 |
+
```text
|
| 529 |
+
L_total = L_human
|
| 530 |
+
+ 0.15 L_teacher-objectness-on-matched-GT
|
| 531 |
+
+ 0.25 L_teacher-box-on-matched-GT
|
| 532 |
+
+ 0.35 L_teacher-empty-window-negative
|
| 533 |
+
```
|
| 534 |
+
|
| 535 |
+
Teacher scores below 0.05 are ignored. Matched proposals supply a BCE confidence target and Smooth-L1
|
| 536 |
+
encoded-box target. A proposal in a human-empty window pushes the corresponding student objectness
|
| 537 |
+
toward zero. An unmatched teacher proposal never creates a positive label. The teacher is therefore a
|
| 538 |
+
ranking guide and hard-negative miner, not a replacement annotator.
|
| 539 |
+
|
| 540 |
+
### 10.4 Optimization protocol
|
| 541 |
+
|
| 542 |
+
The final A100 run used 36 epochs, 260 updates per epoch, and 9,360 optimizer steps:
|
| 543 |
+
|
| 544 |
+
| Item | Final setting |
|
| 545 |
+
|---|---:|
|
| 546 |
+
| Optimizer | Adam |
|
| 547 |
+
| Initial / minimum LR | 5×10⁻⁴ / 1×10⁻⁵ |
|
| 548 |
+
| Warm-up / schedule | 100 steps / cosine decay |
|
| 549 |
+
| Precision | FP32; TF32 disabled |
|
| 550 |
+
| Gradient-norm clip | 1.0 |
|
| 551 |
+
| Batch / segment | 16 / 20 windows |
|
| 552 |
+
| Negative/positive target | 2.0 |
|
| 553 |
+
| Maximum oversampling | 4.0× |
|
| 554 |
+
| Human box loss | pixel-inclusive CIoU, weight 2.0 |
|
| 555 |
+
| Auxiliary segmentation | BCE, weight 0.5 |
|
| 556 |
+
| Objectness target floor | 1.0 throughout |
|
| 557 |
+
| Quality head / loss | disabled / 0.0 |
|
| 558 |
+
| Seed | 1337 |
|
| 559 |
+
|
| 560 |
+
Adam state, scheduler, RNG, batching order, partial epoch progress, preprocessing fingerprint, and the
|
| 561 |
+
training contract were included in exact-resume checkpoints. A remote disconnect therefore resumed
|
| 562 |
+
the same stochastic run rather than launching a similar but different experiment.
|
| 563 |
+
|
| 564 |
+
### 10.5 Evaluation methodology
|
| 565 |
+
|
| 566 |
+
Predictions are scored only after native mapping, calibration, tracking, clipping, top-one selection,
|
| 567 |
+
sensor output gating, and integer writer projection. IoU uses the official pixel-inclusive convention.
|
| 568 |
+
Metrics are reported for the three-sequence leakage-free aggregate and all four local recordings.
|
| 569 |
+
Because every remaining recording has influenced diagnostics, these are reproducibility and local
|
| 570 |
+
comparison results—not blind-generalization proof. Latency is measured after warm-up at streaming
|
| 571 |
+
batch one and reports mean, per-sequence p95, and maximum rather than forward-pass mean alone.
|
| 572 |
+
|
| 573 |
+
## 11. Final model architecture: complete component reference
|
| 574 |
+
|
| 575 |
+
### 11.1 Frozen architecture contract
|
| 576 |
+
|
| 577 |
+
| Property | Final value |
|
| 578 |
+
|---|---:|
|
| 579 |
+
| Class | `OrbitSightDetector` |
|
| 580 |
+
| Inference input | 1×3×640×640 |
|
| 581 |
+
| Backbone widths | 4, 8, 16, 32 |
|
| 582 |
+
| ConvLSTM dilations | 1, 2, 4, 8 |
|
| 583 |
+
| Detection scales | stride 4, 8, 16 |
|
| 584 |
+
| Head width | 16 |
|
| 585 |
+
| Classes | one RSO foreground class |
|
| 586 |
+
| Stored parameters | 135,111 |
|
| 587 |
+
| Quality head / sensor FiLM | absent / absent |
|
| 588 |
+
| Auxiliary segmentation | stored; training-only execution |
|
| 589 |
+
| Classification towers | stored for compatibility; never executed |
|
| 590 |
+
|
| 591 |
+

|
| 592 |
+
|
| 593 |
+
### 11.2 Compression decision
|
| 594 |
|
| 595 |
| Component | Heavy V5/V7 branch | CPU student |
|
| 596 |
|---|---:|---:|
|
| 597 |
| Input | 3×640×640 | 3×640×640 |
|
| 598 |
| Backbone widths | 32, 64, 128, 256 | 4, 8, 16, 32 |
|
| 599 |
+
| Head width | 128 | 16 |
|
| 600 |
+
| Dilations | 1, 2, 4, 8 | 1, 2, 4, 8 |
|
| 601 |
| Parameters | 8,588,339 | 135,111 |
|
| 602 |
+
| Runtime role | Offline teacher | Deployed model |
|
|
|
|
| 603 |
|
| 604 |

|
| 605 |
|
| 606 |
+
The 63.6× reduction comes mainly from channel width. Input resolution, recurrence, the finest stride-4
|
| 607 |
+
grid, and three detection scales remain because spatial quantization is expensive for 6–11 pixel targets.
|
|
|
|
|
|
|
| 608 |
|
| 609 |
+
### 11.3 Input representation
|
| 610 |
|
| 611 |
+
`X ∈ R^(B×3×640×640)` is float32. Channel 0 counts positive-polarity events; channel 1 counts negative
|
| 612 |
+
events; channel 2 records normalized recency of the latest event. Empty pixels are zero. This preserves
|
| 613 |
+
brightness-change sign and within-window order without reconstructing an intensity image.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 614 |
|
| 615 |
+
### 11.4 Stem
|
|
|
|
|
|
|
| 616 |
|
| 617 |
+
```text
|
| 618 |
+
(B,3,640,640)
|
| 619 |
+
→ Conv2d(3→4, kernel 3, stride 1, pad 1)
|
| 620 |
+
→ BatchNorm2d(4) → SiLU
|
| 621 |
+
= (B,4,640,640)
|
| 622 |
+
```
|
| 623 |
+
|
| 624 |
+
The stem has 120 parameters. SiLU is `x·sigmoid(x)`. There is no pooling or tokenization.
|
| 625 |
+
|
| 626 |
+
### 11.5 Four downsampling and recurrent stages
|
| 627 |
+
|
| 628 |
+
Each stage performs 3×3 stride-2 convolution, BatchNorm, SiLU, then ConvLSTM. There are no residual
|
| 629 |
+
blocks, attention layers, transformer tokens, or active sensor-conditioning layers.
|
| 630 |
+
|
| 631 |
+
| Stage | Down mapping | Feature and state | Dilation | Down params | ConvLSTM params | Head input? |
|
| 632 |
+
|---|---|---|---:|---:|---:|---|
|
| 633 |
+
| 1 | 4→4 | B×4×320×320 | 1 | 156 | 1,168 | No |
|
| 634 |
+
| 2 | 4→8 | B×8×160×160 | 2 | 312 | 4,640 | Yes, stride 4 |
|
| 635 |
+
| 3 | 8→16 | B×16×80×80 | 4 | 1,200 | 18,496 | Yes, stride 8 |
|
| 636 |
+
| 4 | 16→32 | B×32×40×40 | 8 | 4,704 | 73,856 | Yes, stride 16 |
|
| 637 |
+
|
| 638 |
+
Stage 1 still matters: its high-resolution recurrent output feeds all later stages. The last three
|
| 639 |
+
tensors are independent multi-scale features. Unlike a classical FPN, there is **no top-down pathway,
|
| 640 |
+
lateral addition, or cross-scale fusion**.
|
| 641 |
+
|
| 642 |
+
### 11.6 Every ConvLSTM operation
|
| 643 |
|
| 644 |
+
At time `t`, current feature `X_t` and previous hidden state `H_(t−1)` are concatenated. One dilated
|
| 645 |
+
3×3 convolution emits four channel groups:
|
|
|
|
|
|
|
| 646 |
|
| 647 |
+
```text
|
| 648 |
+
[I,F,O,G] = Conv3×3_dilated([X_t,H_(t−1)])
|
| 649 |
+
i=sigmoid(I), f=sigmoid(F), o=sigmoid(O), g=tanh(G)
|
| 650 |
+
C_t = f ⊙ C_(t−1) + i ⊙ g
|
| 651 |
+
H_t = o ⊙ tanh(C_t)
|
| 652 |
+
```
|
| 653 |
+
|
| 654 |
+
The input, forget, and output gates govern writing, retaining, and exposing memory. Both `H_t` and
|
| 655 |
+
`C_t` persist. At inference the four pairs have shapes 1×4×320×320, 1×8×160×160,
|
| 656 |
+
1×16×80×80, and 1×32×40×40. Dilation gives effective 3×3, 5×5, 9×9, and 17×17 footprints without
|
| 657 |
+
adding weights. State begins at zero and resets only at sequence boundaries.
|
| 658 |
+
|
| 659 |
+
### 11.7 Three active detection heads
|
| 660 |
+
|
| 661 |
+
For each returned feature, the active regression/objectness tower is:
|
| 662 |
+
|
| 663 |
+
```text
|
| 664 |
+
feature C×H×W
|
| 665 |
+
→ Conv2d(C→16,3×3,pad1) → SiLU
|
| 666 |
+
→ Conv2d(16→16,3×3,pad1) → SiLU
|
| 667 |
+
├→ Conv2d(16→4,1×1): raw box vector
|
| 668 |
+
└→ Conv2d(16→1,1×1): objectness logit
|
| 669 |
+
```
|
| 670 |
+
|
| 671 |
+
| Scale | Feature | Tower + box + objectness params | Outputs |
|
| 672 |
+
|---|---:|---:|---|
|
| 673 |
+
| stride 4 | 8×160×160 | 3,488 + 68 + 17 | 4×160×160 and 1×160×160 |
|
| 674 |
+
| stride 8 | 16×80×80 | 4,640 + 68 + 17 | 4×80×80 and 1×80×80 |
|
| 675 |
+
| stride 16 | 32×40×40 | 6,944 + 68 + 17 | 4×40×40 and 1×40×40 |
|
| 676 |
+
|
| 677 |
+
There are 25,600 + 6,400 + 1,600 = **33,600 candidate cells**. Four regression channels encode raw
|
| 678 |
+
x/y offsets and log width/height. Objectness alone asks whether an RSO occupies the cell.
|
| 679 |
+
|
| 680 |
+
### 11.8 Compatibility classification modules
|
| 681 |
+
|
| 682 |
+
Three classification towers and 1×1 predictors remain in the checkpoint so historical state-dictionary
|
| 683 |
+
keys load strictly. They contain 15,123 parameters, but `compute_cls=False`: their convolutions are not
|
| 684 |
+
executed, their logits are not trained by the final loss, and the decoder never reads them. In a
|
| 685 |
+
single-class problem, multiplying objectness by a redundant class probability would square/compress
|
| 686 |
+
confidence without adding information. Final score is `sigmoid(objectness)`. No quality head exists.
|
| 687 |
+
|
| 688 |
+
### 11.9 Auxiliary segmentation head
|
| 689 |
+
|
| 690 |
+
A nine-parameter 1×1 convolution maps the eight-channel stride-4 feature to one 160×160 logit plane.
|
| 691 |
+
Per-event labels supervise it with BCE at weight 0.5, helping the finest features retain target-local
|
| 692 |
+
structure. It runs only while `model.training` is true; deployment skips it entirely.
|
| 693 |
+
|
| 694 |
+
### 11.10 Target assignment and hard loss
|
| 695 |
+
|
| 696 |
+
A human box is assigned to the scale whose `4×stride` nominal size is closest to its maximum dimension.
|
| 697 |
+
The rounded center and radius-1 neighborhood—up to 3×3 cells—are positive. At cell `(g_x,g_y)`:
|
| 698 |
+
|
| 699 |
+
```text
|
| 700 |
+
t_x=c_x/s−g_x, t_y=c_y/s−g_y,
|
| 701 |
+
t_w=w/s, t_h=h/s
|
| 702 |
+
```
|
| 703 |
+
|
| 704 |
+
Objectness uses focal BCE with alpha 0.25 and gamma 2.0, normalized by positive assigned cells and
|
| 705 |
+
clamped to one on empty windows. The positive objectness floor was 1.0 during final distillation.
|
| 706 |
+
Regression uses pixel-inclusive CIoU: `1−IoU`, normalized center distance, and aspect-ratio penalty.
|
| 707 |
+
It therefore supplies gradient even before two tiny boxes overlap. Auxiliary BCE and the selective KD
|
| 708 |
+
terms described in Section 10 complete the objective.
|
| 709 |
+
|
| 710 |
+
### 11.11 Anchor-free decode
|
| 711 |
+
|
| 712 |
+
For raw `(r_x,r_y,r_w,r_h)` at grid cell `(g_x,g_y)` and stride `s`:
|
| 713 |
+
|
| 714 |
+
```text
|
| 715 |
+
c_x=(g_x+r_x)s c_y=(g_y+r_y)s
|
| 716 |
+
w=exp(clamp(r_w,6))s h=exp(clamp(r_h,6))s
|
| 717 |
+
score=sigmoid(objectness)
|
| 718 |
+
```
|
| 719 |
+
|
| 720 |
+
Offsets are intentionally raw, matching training. Exponentiation guarantees positive sizes and the
|
| 721 |
+
upper clamp prevents overflow.
|
| 722 |
+
|
| 723 |
+
### 11.12 Exact stable top-one decode
|
| 724 |
+
|
| 725 |
+
Production requests one proposal. The decoder concatenates three score maps in fixed scale/grid order,
|
| 726 |
+
masks values below 0.10, and applies `argmax`. Exact ties select the first index deterministically. Only
|
| 727 |
+
the winning cell's box is decoded.
|
| 728 |
+
|
| 729 |
+
This exactly matches the first result of score-ordered NMS: the global maximum is selected before any
|
| 730 |
+
overlap comparison can suppress it. Thus production avoids materializing/sorting 33,600 boxes and the
|
| 731 |
+
Python NMS loop without approximating or changing the selected prediction. Generic pixel-inclusive NMS
|
| 732 |
+
and its 1,000-candidate pre-bound remain only for multi-detection diagnostics.
|
| 733 |
+
|
| 734 |
+
### 11.13 Native-coordinate reconstruction
|
| 735 |
+
|
| 736 |
+
The winning box is inverted through recorded area-resize geometry with pixel-center rounding. DVX
|
| 737 |
+
width/height receives the frozen 0.98 calibration before association. Geometry is clipped in native
|
| 738 |
+
sensor coordinates, but remains floating point until the writer performs final legal integer projection.
|
| 739 |
+
|
| 740 |
+
### 11.14 Complete parameter inventory
|
| 741 |
+
|
| 742 |
+
| Module group | Parameters | Deployment execution |
|
| 743 |
+
|---|---:|---|
|
| 744 |
+
| Stem | 120 | Yes |
|
| 745 |
+
| Four downsampling blocks | 6,372 | Yes |
|
| 746 |
+
| Four ConvLSTM cells | 98,160 | Yes |
|
| 747 |
+
| Three regression towers | 15,072 | Yes |
|
| 748 |
+
| Box predictors | 204 | Yes |
|
| 749 |
+
| Objectness predictors | 51 | Yes |
|
| 750 |
+
| Compatibility classification modules | 15,123 | No |
|
| 751 |
+
| Auxiliary segmentation | 9 | No |
|
| 752 |
+
| **Total** | **135,111** | — |
|
| 753 |
+
|
| 754 |
+
### 11.15 End-to-end state machine
|
| 755 |
+
|
| 756 |
+
For each sequence: identify sensor and reset state; slice 40 ms; denoise; form the 3×640×640 tensor;
|
| 757 |
+
run stem and four ConvLSTMs; run three active heads; choose/decode global top-one; map/calibrate native
|
| 758 |
+
geometry; update Kalman/coast state; retain at most one box; apply the sensor gate; project integer
|
| 759 |
+
fields; write the row; and reset everything before another sequence. Docker latency covers this path,
|
| 760 |
+
not merely the neural forward call.
|
| 761 |
+
|
| 762 |
+
## 12. Detection to tracking
|
| 763 |
|
| 764 |
The detector proposes appearance-based boxes. The tracker imposes short-horizon physical
|
| 765 |
consistency. Each track maintains:
|
|
|
|
| 785 |
motion was slow enough that consecutive boxes overlap. IoU association was therefore more
|
| 786 |
reliable than a complex motion-only discriminator.
|
| 787 |
|
| 788 |
+
## 13. Distilled student results
|
| 789 |
|
| 790 |
Before the final no-retrain adjustments, the distilled checkpoint produced:
|
| 791 |
|
|
|
|
| 810 |
the steady-state p95 objective locally, but scheduling outliers still existed in the longer
|
| 811 |
profile.
|
| 812 |
|
| 813 |
+
## 14. Final no-retrain improvements
|
| 814 |
|
| 815 |
With the checkpoint and architecture frozen, only low-cost constants were screened:
|
| 816 |
|
|
|
|
| 841 |
The gains are modest but consistent across both aggregate views. No weight, layer, or tensor
|
| 842 |
shape changed.
|
| 843 |
|
| 844 |
+
## 15. Current per-sequence behavior
|
| 845 |
|
| 846 |
| Recording | Sensor | F1 | AP | Precision | Recall | Main interpretation |
|
| 847 |
|---|---|---:|---:|---:|---:|---|
|
|
|
|
| 861 |
|
| 862 |

|
| 863 |
|
| 864 |
+
## 16. Docker and reproducibility architecture
|
| 865 |
|
| 866 |
The final Linux/amd64 image is designed to be inspected and run without network access. It
|
| 867 |
contains:
|
|
|
|
| 894 |
mount contract, output schema, model hash, runtime dependencies, calibration constants,
|
| 895 |
tracker settings, and baked model-structure text.
|
| 896 |
|
| 897 |
+
## 17. Evidence boundaries and scientific honesty
|
| 898 |
|
| 899 |
Three different claims must not be confused:
|
| 900 |
|
|
|
|
| 912 |
have still been used for diagnostics. “Leakage-free” here means free of that known training-
|
| 913 |
session contamination, not untouched by all development decisions.
|
| 914 |
|
| 915 |
+
## 18. Why the final student is the recommended submission
|
| 916 |
|
| 917 |
The heavy hybrid has the best local accuracy but fails the CPU requirement by an order of
|
| 918 |
magnitude. V5 has a cleaner scientific history but its corrected full-tail latency exceeded
|
|
|
|
| 932 |
This is a practical systems decision rather than a claim that the student is universally
|
| 933 |
more accurate than every predecessor.
|
| 934 |
|
| 935 |
+
## 19. Recommended next work
|
| 936 |
|
| 937 |
If new recordings become available, the next work should be data-centered rather than another
|
| 938 |
threshold sweep:
|
|
|
|
| 952 |
- measure container startup, file reading, formatting, workbook creation, and disk output on
|
| 953 |
the organizer's exact i9-12900H hardware.
|
| 954 |
|
| 955 |
+
## 20. Conclusion
|
| 956 |
|
| 957 |
OrbitSight progressed from an honest sub-0.1 baseline to a complete real-time CPU system by
|
| 958 |
treating data contracts, localization, temporal reasoning, deployment, and evaluation as one
|
|
|
|
| 968 |
|
| 969 |
## Selected references
|
| 970 |
|
| 971 |
+
1. G. Gallego et al., “Event-based Vision: A Survey,” IEEE TPAMI, 2020.
|
| 972 |
+
DOI: 10.1109/TPAMI.2020.3008413.
|
| 973 |
+
2. S. Afshar et al., “Event-based Object Detection and Tracking for Space Situational
|
| 974 |
+
Awareness,” arXiv:1911.08730, 2019.
|
| 975 |
+
3. N. O. Ralph et al., “Astrometric Calibration and Source Characterisation of the Latest
|
| 976 |
+
Generation Neuromorphic Event-based Cameras for Space Imaging,” arXiv:2211.09939, 2022.
|
| 977 |
+
4. Y. Alkendi et al., “Dynamic Space Object Detection with Neuromorphic Vision Sensors,”
|
| 978 |
European Conference on Space Debris, 2025.
|
| 979 |
+
5. E. Perot et al., “Learning to Detect Objects with a 1 Megapixel Event Camera,” NeurIPS, 2020.
|
| 980 |
+
6. M. Gehrig and D. Scaramuzza, “Recurrent Vision Transformers for Object Detection with
|
| 981 |
Event Cameras,” CVPR, 2023.
|
| 982 |
+
7. X. Shi et al., “Convolutional LSTM Network: A Machine Learning Approach for Precipitation
|
| 983 |
+
Nowcasting,” NeurIPS, 2015.
|
| 984 |
+
8. Z. Tian et al., “FCOS: Fully Convolutional One-Stage Object Detection,” ICCV, 2019.
|
| 985 |
+
9. Z. Ge et al., “YOLOX: Exceeding YOLO Series in 2021,” arXiv:2107.08430, 2021.
|
| 986 |
+
10. T.-Y. Lin et al., “Focal Loss for Dense Object Detection,” ICCV, 2017.
|
| 987 |
+
11. Z. Zheng et al., “Distance-IoU Loss: Faster and Better Learning for Bounding Box
|
| 988 |
+
Regression,” AAAI, 2020. DOI: 10.1609/aaai.v34i07.6999.
|
| 989 |
+
12. G. Hinton, O. Vinyals, and J. Dean, “Distilling the Knowledge in a Neural Network,”
|
| 990 |
+
arXiv:1503.02531, 2015.
|
| 991 |
+
13. Y. Zhang et al., “ByteTrack: Multi-Object Tracking by Associating Every Detection Box,”
|
| 992 |
+
ECCV, 2022.
|
| 993 |
|
| 994 |
## Primary local evidence
|
| 995 |
|