asferrer/gemma-4-E2B-it-oceanguard-marine-debris

Gemma 4 E2B — OceanGuard Marine Debris LoRA Adapter

A LoRA fine-tune of `google/gemma-4-E2B-it` that adapts the model to open-vocabulary detection of anthropogenic marine debris on consumer mobile hardware. The adapter is the training artefact behind the OceanGuard AI Android application — a fully offline marine-debris intelligence toolkit submitted to the Kaggle Gemma 4 Good Hackathon (Global Resilience track, Unsloth $10 K bonus) and built on top of two prior peer-reviewed publications on underwater debris detection (Sánchez-Ferrer et al., PRL 2023; IbPRIA 2022).

Headline result. On the held-out evaluation split (n = 200 stratified samples, real_test_holdout.jsonl) the LoRA fine-tune reaches mAP@0.5 = 0.3256, against 0.1067 for the unmodified base model (Δ = +0.2189, a +205 % relative improvement). The winner is exp12_vision_lora, which unfreezes the SigLIP2 vision encoder via LoRA on top of the language-only adapter. Canonical metrics are tracked in finetune/experiments/results/best.json and results.md of the source repository.

Files in This Repository

This repository ships the LoRA adapter artefacts. The LiteRT-LM runtime build (.litertlm) is in progress — see §Deployment for the current status:

The adapter is fully reproducible and usable today via PEFT / Unsloth. The GGUF Q4KM build is available for immediate use with llama.cpp and the OceanGuard Android app. The .litertlm export depends on Gemma 4 support landing in MediaPipe's tasks.python.genai.converter or in ai-edge-torch. See §Deployment.

Model Description

OceanGuard AI runs Gemma 4 E2B fully on-device on a Samsung Galaxy S22 Ultra (Exynos 2200, CPU + Vulkan/Xclipse 920) for open-vocabulary deep analysis of marine debris over a 50-class taxonomy that collapses down to 11 canonical ecological-impact families (BOTTLE, CAN, FISHING_NET, GLOVE, MASK, METAL_DEBRIS, PLASTIC_DEBRIS, TIRE, FABRIC_DEBRIS, GLASS_DEBRIS, OTHER).

This adapter aligns Gemma 4 E2B with the exact structured output contract that the Android application consumes — a JSON array of {box_2d, label, material} objects — and reduces the rate at which detections fall through to the generic PLASTIC_DEBRIS catch-all. The same LoRA also improves material attribution for the downstream ecological-impact lookup that drives the app's health-score and report-generation pipelines.

The adapter is distributed as a standard PEFT LoRA (≈120 MB safetensors, r=16, α=32) attached to a bf16 base model. Compared to a language-only adapter, the published model additionally adapts the SigLIP2 vision encoder via the same low-rank decomposition — this is what unlocks the dramatic gain on texture-heavy classes (Fishing_Net, Glove) reported below.

Intended Use

In-scope use cases.

• —Mobile and edge marine-debris detection for citizen science, NGO field operations, and coastal monitoring campaigns.
• —Research baselines for open-vocabulary detection over specialised environmental taxonomies.
• —A grounding component for tool-augmented reporting pipelines (see the OceanGuard single-conversation agentic tool-calling architecture).

Out-of-scope use cases.

• —Autonomous decision-making (cleanup dispatch, regulatory enforcement, environmental fines). This model is a triage and reporting aid; final decisions must remain with a qualified human.
• —Real-time safety-critical detection (collision avoidance, navigation). End-to-end latency on the reference device is on the order of seconds per image.
• —General-purpose object detection outside the marine-debris domain — the adapter narrows the visual prior towards marine debris and may degrade on unrelated tasks.

Training Data

The training set is a permissive-license merge of three open marine-debris datasets, including the CleanSea corpus introduced by the model author (IbPRIA 2022), plus a synthetic-renders set that expands the rare-class footprint:

The ablation grid was run over twelve dataset compositions that vary the ratio of synthetic-to-real images and the LoRA target modules. The published adapter corresponds to experiment exp12_vision_lora, which uses the largest available training mix (n = 24 446 samples: 10 809 synthetic + 13 637 real) combined with the vision-encoder LoRA that the language-only experiments leave untouched. The held-out evaluation set is a separate 200-sample stratified split from real_test_holdout.jsonl never seen during training. The 8-class taxonomy (Bottle, Can, Fishing_Net, Glove, Mask, Metal_Debris, Plastic_Debris, Tire) is extended at inference time to a 50-class fine-grained vocabulary that is mapped back to the 11 canonical families through a deterministic lookup table; see Gemma4VisionDetector.LABEL_TO_TYPE in the Android source for the full mapping.

Geographic coverage. The three source datasets were collected predominantly in coastal waters around Japan and the wider north-western Pacific. As a result the training distribution is biased towards the debris taxonomy, water clarity, lighting and sediment patterns of that region. This is reflected in the §Limitations and §Bias sections below; users surveying outside Japan-Pacific waters should expect a measurable domain shift and validate the adapter on a local hold-out before operational use.

Re-distributors of the merged dataset must comply with the original dataset licenses.

Training Procedure

The published adapter is the winner of a 12-experiment LoRA ablation grid. All runs used Unsloth FastVisionModel 2026.5.2 on a single workstation GPU, in bf16.

Configuration (best: exp12_vision_lora)

Why training stopped at step 1 150

The vision-encoder LoRA roughly doubles the trainable parameter count compared to a language-only adapter, which raises the peak Windows commit charge (RAM + pagefile) for the training process beyond the 112 GB ceiling configured on the training workstation (96 GB physical RAM + 16 GB pagefile). After two CUDA / OS-level crashes during the original 3-epoch run, the experiment was restarted with a multi-resume strategy (200-step chunks, fresh Python process each chunk to drain the PIL-image cache held by the eager dataset loader). The first chunk produced checkpoint-1150 — and an intermediate evaluation showed that the model had already overtaken the previous language-only winner (exp10_real_full, mAP@0.5 = 0.3253). The orchestrator therefore promoted checkpoint-1150 to the canonical artefact and stopped further chunks. Full 3-epoch training on this configuration would require a larger pagefile or a lazy-loading data collator — both noted in the project roadmap.

Convergence

Loss decreased monotonically from 14.78 at step 10 to 0.4991 at step 1 150; the last 20 logging windows had a standard deviation of ≈ 0.013 and a minimum loss of 0.4991 at step 1 150, with no late-stage divergence. The language-only baseline (exp11_real_synth_full, identical data) reached 0.5224 at the same step — the vision LoRA delivered a sustained ≈ 0.022 absolute (≈ 4 %) loss advantage from step 250 onwards.

Hardware and wall-clock

• —1× NVIDIA RTX 5090 (32 GiB GDDR7), Windows 11, CUDA 12.8, PyTorch 2.7
• —Training wall-clock: ≈ 5 h 30 min end-to-end (initial run to step 1 097 + recovery cycle to step 1 150 + final eval)
• —Deployment target: Samsung Galaxy S22 Ultra (Exynos 2200) via LiteRT-LM 0.11.0

Software

unsloth 2026.5.2 · transformers 5.5.0 · peft · trl · accelerate · bitsandbytes · torch 2.7.0+cu128.

The complete reproducible pipeline (prepare_datasets → generate_configs → run_experiments → eval_grid → collect_results → auto_promote_best) is published in the source repository under OceanguardAI-App/finetune/experiments/. The multi-resume orchestrator (finetune/multi_resume_exp12.py) and the WMI-hang workaround (finetune/wmi_bypass.py) used to recover the published checkpoint are also included.

Evaluation

All runs are evaluated on the held-out evaluation split of the merged dataset, with the same JSON contract and post-processing as the production Android app (temperature = 0.0, max_new_tokens = 256). The canonical metrics in finetune/experiments/results/best.json and results.md are reproduced verbatim in the tables below.

Aggregate

Per-class mAP@0.5

Compared to the language-only adapter (exp10_real_full), the vision LoRA delivers dramatic gains on texture-rich classes (Fishing_Net 0.448 → 0.575 = +0.127; Glove 0.463 → 0.498 = +0.035), modest gains on Mask and Can, and small regressions on Plastic_Debris, Bottle and Tire that the global mAP@0.5 still overtakes. Metal_Debris remains unlearned even with the vision encoder unfrozen, confirming that the bottleneck for that specific class is data scarcity rather than visual representation. The full ablation grid (exp01 … exp12) and class-wise comparison against the base model are recorded in finetune/experiments/results/results.md in the source repository.

Per-source mAP@0.5 (stratified breakdown)

To validate that the gain is not driven by a single source dataset, the same 200-image stratified test split is broken down by the originating dataset. The LoRA improves over the base in every source, with the largest relative uplift on CleanSea — the smallest training subset and the project's own benchmark from IbPRIA 2022.

Notes on this breakdown:

• —The values are computed with the same VOC 11-point AP fallback used by the project's eval_grid.manual_map_eval (matches the global card row within ≤ 0.002 rounding versus the pycocotools COCO-standard pass that produced 0.3256).
• —CleanSea (n = 19) is the smallest subset and therefore the 6.54× ratio has wider confidence; treat it as a strong directional signal rather than a tight point estimate.
• —The eval split is not contaminated: the 200 ids are a subset of real_test_holdout.jsonl, none of which appears in any experiments/splits/exp*/train.jsonl. The companion eval dataset on Hugging Face, `asferrer/oceanguard-marine-debris-eval-1000`, ships the full annotation set plus compute_per_source_map.py for independent verification.

Deployment

The adapter targets two on-device runtimes on Exynos 2200:

1. 1.GGUF + llama.cpp (available now): the merged model is quantized to Q4KM and served via the llama.cpp engine already integrated in the OceanGuard Android app.
2. 2.LiteRT-LM (pending): the .litertlm export is blocked on upstream converter support for the Gemma 4 / Gemma3n architecture.

GGUF Download

# Direct download URL
curl -L -o gemma-4-E2B-it-oceanguard-Q4_K_M.gguf \
  "https://huggingface.co/asferrer/gemma-4-E2B-it-oceanguard-marine-debris/resolve/main/gemma-4-E2B-it-oceanguard-Q4_K_M.gguf"

Load with llama.cpp:

./llama-cli -m gemma-4-E2B-it-oceanguard-Q4_K_M.gguf \
  -n 256 --temp 0.3 --top-k 20 \
  -p "Analyze this marine debris image and output JSON: {\"detections\": [...]}"

In-App Selection

The OceanGuard Android app exposes the GGUF variant under Settings > VLM Model > Provider: "Gemma 4 FT (GGUF)" > Tier: "Gemma 4 FT (OceanGuard)". The download button fetches the ~3.4 GB GGUF directly from this repository. The BASE Gemma 4 E2B (LiteRT-LM) remains the default and is unaffected.

Reference benchmarks on the deployment target (Galaxy S22 Ultra, Exynos 2200, LiteRT-LM 0.11.0, Vulkan via Xclipse 920 — BASE model):

• —Decode throughput: 5.1 tok/s (BASE LiteRT-LM); GGUF expected ~4-5 tok/s CPU-only
• —Time to first token (warm / cold first load): 2.33 s / 17.34 s
• —Prefill throughput: 48.7 tok/s
• —Single-shot detection, ~100-token JSON output: ≈ 22 s end-to-end

Limitations

• —Fixed-with-fallback taxonomy. The fine-tune adheres to an 8-class core extended to 50 fine-grained classes. Out-of-distribution debris (polar microplastic, deep-sea anthropogenic objects) is not represented in the training data and will be mapped to the generic catch-all classes.
• —CPU + Vulkan-only inference on the reference device. The Exynos 2200 GPU pass via Vulkan improves correctness but not throughput; on this hardware Gemma 4 E2B is reserved for single-shot deep analysis (≈ 20 s end-to-end per image), not for continuous live-camera operation.
• —Geographic bias. The training imagery is predominantly sourced from coastal waters around Japan and the broader north-western Pacific. Performance on the Mediterranean, tropical reefs, polar seas, the south Atlantic and freshwater debris surveys is expected to be lower and is not yet measured. Users surveying outside Japan-Pacific waters should treat the model as a baseline and validate against a local hold-out set before drawing conclusions.
• —Lighting and capture bias. Synthetic-augmentation passes can inject lighting biases that may degrade under poor underwater visibility.
• —`Metal_Debris` remains unlearned. Despite unfreezing the vision encoder via LoRA, Metal_Debris per-class mAP@0.5 stays at 0.000, identical to the language-only baseline. This rules out visual representation as the bottleneck and points to either label ambiguity in the test split (overlap with Tire, Plastic_Debris, Other_metal_objects) or insufficient ground-truth instances. A class-balanced data campaign and a per-class label audit are planned.
• —`Can` improves but remains weak. mAP@0.5 = 0.091. Operators should expect silent misses on this class and gate critical decisions accordingly.
• —JSON validity is 88.5 %, not 100 %. Roughly 1 in 9 detections in the eval set emerge in malformed JSON and are dropped by the parser. The Android app handles these gracefully by surfacing an empty detection set to the user rather than fabricating boxes. The drop from the language-only baseline (94.5 %) is the cost the vision LoRA pays for the higher recall on texture-rich classes — it is the dominant remaining failure mode.
• —Trained to step 1 150 of a 2 292-step plan. The published checkpoint reaches the ablation-grid winner mAP but was halted before full 3-epoch convergence (see §Training Procedure). Further training on a workstation with a larger pagefile or with a lazy-loading collator is expected to refine these numbers modestly, particularly on Plastic_Debris, Bottle and Tire which regressed slightly versus the language-only winner.
• —Not certified. This model is not certified for legal, regulatory or environmental enforcement reporting. The OceanGuard app produces draft reports that a human reviews before any official use.
• —Function-calling head untouched. The fine-tune is intentionally scoped to the detection head and does not rewrite tool-calling syntax, to avoid regressing the single-conversation agentic tool-calling pipeline that the Android app depends on for grounded report generation.

Bias, Risks and Safety

• —Spurious-correlation risk. Marine-debris classes co-occur with characteristic backgrounds (e.g. fishing nets with rocky shorelines). The model may exploit context cues that do not generalise across geographies.
• —Sensitive categories. The syringe / medical waste class is rare and high-stakes; positive detections should trigger human handling protocols rather than autonomous action.
• —Citizen-science abuse vectors. As with any open-vocabulary detector, the model can be prompted to label arbitrary objects; downstream applications should constrain inputs to the marine-debris domain and filter implausible outputs (the OceanGuard app does this via LABEL_TO_TYPE and the canonical 11-class projection in EnvironmentalImpact.IMPACT_MAP).
• —Privacy. Photos analysed on-device in OceanGuard never leave the phone; this adapter itself processes no user data. When used outside the app, downstream operators are responsible for compliance with applicable privacy regulation.

How to Use

A. Research / training pipeline — PEFT + Unsloth

from unsloth import FastVisionModel

model, tokenizer = FastVisionModel.from_pretrained(
    "unsloth/gemma-4-E2B-it",
    load_in_4bit=True,
)
model.load_adapter(
    "asferrer/gemma-4-E2B-it-oceanguard-marine-debris",
    adapter_name="oceanguard",
)
model.set_adapter("oceanguard")
FastVisionModel.for_inference(model)

# Use the exact DETECTION_PROMPT shipped in the Android app — see
# docs/submission/notebook_finetune.ipynb for the verbatim string and helper.

A fully reproducible end-to-end example (image loading, inference, JSON parsing, visualisation and quantitative evaluation) lives at `docs/submission/notebook_finetune.ipynb` in the source repository.

B. On-device deployment — GGUF Q4KM via llama.cpp (available now)

# Download the GGUF directly from this repository (~3.4 GB; 5.88 BPW due to 262k vocab)
curl -L -o gemma-4-E2B-it-oceanguard-Q4_K_M.gguf \
  "https://huggingface.co/asferrer/gemma-4-E2B-it-oceanguard-marine-debris/resolve/main/gemma-4-E2B-it-oceanguard-Q4_K_M.gguf"

# Run inference with llama.cpp
./llama-cli -m gemma-4-E2B-it-oceanguard-Q4_K_M.gguf \
  -n 512 --temp 0.3 --top-k 20 \
  -p "<start_of_turn>user\nAnalyze this marine debris and output JSON boxes:<end_of_turn>\n<start_of_turn>model\n"

The OceanGuard Android app downloads and loads this GGUF automatically via the "Gemma 4 FT (GGUF)" provider selector in Settings, using LlamaTextEngine (llama.cpp) with nCtx=8192, temperature=0.3, topK=20.

C. On-device deployment — direct .litertlm download (pending upstream)

Once the .litertlm export lands (see §Deployment), it will live at the URL below and the Android app's LiteRT-LM FINETUNED slot will become active:

# Direct download URL (will return 404 until the .litertlm is uploaded)
curl -L -o gemma-4-E2B-it-oceanguard.litertlm \
  "https://huggingface.co/asferrer/gemma-4-E2B-it-oceanguard-marine-debris/resolve/main/gemma-4-E2B-it-oceanguard.litertlm"

License and Citation

• —LoRA adapter — Apache 2.0
• —Base model — google/gemma-4-E2B-it, subject to the Gemma Terms of Use
• —Training datasets — source-dataset licenses apply (CC-BY or equivalent; see dataset cards)

@misc{sanchezferrer2026oceanguard_adapter,
  author       = {S{\'a}nchez-Ferrer, Alejandro},
  title        = {{Gemma 4 E2B OceanGuard Marine Debris LoRA Adapter}},
  year         = {2026},
  howpublished = {HuggingFace Model Hub},
  note         = {LoRA adapter for google/gemma-4-E2B-it. Apache 2.0.},
  url          = {https://huggingface.co/asferrer/gemma-4-E2B-it-oceanguard-marine-debris}
}

@misc{sanchezferrer2026oceanguard_app,
  author       = {S{\'a}nchez-Ferrer, Alejandro},
  title        = {{OceanGuard AI: Fully Offline Marine Debris Intelligence with Gemma 4 and Two-Phase Tool Calling}},
  year         = {2026},
  howpublished = {Kaggle Gemma 4 Good Hackathon (Global Resilience track)},
  url          = {https://github.com/asferrer/OceanguardAI-App}
}

Related Publications by the Author

This adapter is the latest iteration of an ongoing line of research on automated detection and recognition of underwater anthropogenic debris.

Peer-reviewed papers

1. 1.Sánchez-Ferrer, A., Valero-Mas, J. J., Gallego, A. J., & Calvo-Zaragoza, J. (2023). An experimental study on marine debris location and recognition using object detection. Pattern Recognition Letters, 168, 154–161. https://doi.org/10.1016/j.patrec.2022.12.019

1. 1.Sánchez-Ferrer, A., Gallego, A. J., Valero-Mas, J. J., & Calvo-Zaragoza, J. (2022). The CleanSea Set: A Benchmark Corpus for Underwater Debris Detection and Recognition. In Iberian Conference on Pattern Recognition and Image Analysis (IbPRIA 2022), Lecture Notes in Computer Science, Springer. doi.org/10.1007/978-3-031-04881-4_49

Theses

1. 1.Sánchez-Ferrer, A. (2024). Modelos de difusión aplicados a la detección de objetos en el fondo marino. Master's Thesis, Universidad de Alicante. rua.ua.es/…/88244474

1. 1.Sánchez-Ferrer, A. (2021). Deep Learning aplicado a la detección de residuos en el fondo marino. Bachelor's Thesis, Universidad de Alicante. rua.ua.es/…/92c34588

Applied research

1. 1.Sánchez-Ferrer, A. (2025). OceanGuard AI: Mapping and Mitigating Marine Pollution. Kaggle hackathon write-up. Kaggle write-up

The CleanSea corpus introduced in (2) is one of the three sources used to train this adapter; the detection methodology developed in (1) defines the marine-debris recognition task that this fine-tune operationalises on-device with Gemma 4 E2B; (3) and (4) lay the foundational work on which the present model card builds.

Acknowledgments

• —Google DeepMind for releasing Gemma 4 under terms that enable open research and on-device deployment.
• —The Unsloth team for the FastVisionModel implementation that makes a Gemma 4 vision-language fine-tune tractable on a single workstation GPU.
• —CleanSea, Ocean_garbage and Neural_Ocean dataset authors for releasing marine-debris annotations under permissive terms.
• —Google AI Edge / LiteRT-LM team for the on-device runtime that hosts the base model in the OceanGuard Android app.
• —Pattern Recognition and Artificial Intelligence (PRAI) group, Universidad de Alicante — research group hosting the doctoral programme under which this work is carried out, and co-authors of the prior publications cited above.