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RSJEV: Discriminative Remote Sensing Scene Classification with Multimodal Large Language Models
Dongchen Si, Di Wang, Mingzhen Xu, Jing Zhang, Bo Du, Liangpei Zhang
TL;DR
Remote sensing scene classification faces limitations in fixed-label visual classifiers, static image-text similarity, and autoregressive MLLM generation for explicit candidate sets. RSJEV uses a candidate-conditioned one-pass multimodal decision process, and reports the highest precision, recall, F1, and overall accuracy across three benchmarks alongside lower inference costs than generative MLLMs.
Problem
Visual classifiers use predefined label spaces, CLIP-based methods rely on image-text similarity, and generative MLLMs can require multiple decoding steps for explicit-category classification.
Source: §I · p. 1Method
RSJEV jointly models image representations, task instructions, and candidate semantics, using an answer-slot decision representation to score categories without autoregressive generation.
Source: §I · pp. 1–2Results
RSJEV achieves the highest precision, recall, F1-score, and overall accuracy across UCM, AID, and NWPU, with F1-scores of 97.72%, 96.30%, and 94.58%, respectively.
Source: 1) Quantitative Analyses · p. 4Takeaways & Limitations
The results highlight the potential of JEV-style multimodal discriminative modeling as a decision paradigm for remote sensing and a direction toward more efficient, scalable multimodal foundation models.
Source: §V · p. 6
Abstract
from arXiv · showhide
Remote sensing scene classification is a fundamental task in Earth observation and geospatial analysis. Existing approaches mainly follow three paradigms: task-specific visual classification, vision-language similarity matching, and autoregressive multimodal generation. However, visual classifiers rely on predefined label spaces, CLIP-based methods perform recognition through static image-text alignment, and multimodal large language models (MLLMs) introduce unnecessary token-level generation for classification tasks with explicit candidate categories. To address these limitations, we propose RSJEV, a one-pass multimodal decision framework for remote sensing scene classification. Unlike conventional MLLMs that formulate classification as autoregressive text generation, RSJEV reformulates scene classification as a candidate-conditioned multimodal discriminative decision process, where visual representations, task instructions, and candidate category semantics are jointly modeled. Specifically, we introduce a OnePass Decider that extracts multimodal decision states and directly estimates category probabilities within the candidate category space, eliminating autoregressive decoding while preserving vision-language interactions. Extensive experiments on three widely used remote sensing scene classification benchmarks, including UC Merced, AID, and NWPU-RESISC45, demonstrate that RSJEV achieves superior classification performance compared with representative CNN-, Transformer-, Mamba-, CLIP-, and MLLM-based methods. Moreover, RSJEV significantly reduces inference costs and achieves a better accuracy-efficiency trade-off with only a compact 0.8B-parameter model. These results demonstrate the effectiveness of state-conditioned multimodal decision making for efficient remote sensing image understanding. The code will be available at https://github.com/Dongtcs/RSJEV.
I. INTRODUCTION
RSJEV replaces iterative text generation for remote sensing scene classification with candidate-conditioned, one-pass multimodal decisions. The paper reports competitive accuracy with lower inference latency than generative MLLMs across three benchmarks.
I. INTRODUCTION
- Remote sensing scene classification is challenged by intra-class variability, inter-class visual similarity, and differences in spatial resolution.The task provides scene-level semantic information for geospatial applications.Source: §I · p. 1
- Task-specific visual classifiers use predefined label spaces and do not explicitly incorporate natural-language category semantics into prediction.The passage notes visually confusing categories such as desert versus barren land and railway versus freeway.Source: §I · p. 1
- CLIP-style methods use image-text embedding similarity, while generative MLLMs can require multiple decoding steps to produce category answers.The passages identify limited direct interaction in similarity-based prediction and added latency and computational cost from iterative generation.Source: §I · p. 1
- RSJEV jointly models visual representations, task instructions, and candidate category semantics to make one-pass discriminative decisions.Its OnePass Decider extracts an answer-slot representation and scores candidate options without autoregressive answer generation.Source: §I · pp. 1–2
- Across three benchmarks, RSJEV achieves competitive accuracy with significantly lower inference latency than generative MLLMs.The introduction reports comprehensive ablations alongside the benchmark experiments.Source: §I · p. 2
II. RELATED WORK
Related work spans task-specific visual models, contrastive vision-language approaches, and generative MLLMs. RSJEV instead conditions a discriminative decision representation on image content, instructions, and candidate categories.
II. RELATED WORK
- Task-specific CNN, Transformer, and state-space models generally use classification heads over predefined category spaces, limiting adaptability to dynamic and open-vocabulary scenarios.Examples include ResNet, DenseNet, EfficientNet, Vision Transformer, Swin Transformer, and RSMamba.Source: §II · p. 2
- Contrastive remote-sensing models classify by comparing image and candidate-category text embeddings, rather than jointly conditioning a decision representation on image, instructions, and candidates.RemoteCLIP and SkyScript are cited as domain-oriented image-text alignment efforts.Source: §II · pp. 2–3
- Generative MLLMs produce autoregressive responses, whereas RSJEV extracts an answer-slot representation and scores candidate options without iterative answer generation.RSJEV conditions this decision on image content, task instructions, and candidate category semantics.Source: §II · pp. 2–3
III. METHODOLOGY
The formulation treats scene classification as choosing among an ordered set of candidate categories, with the image and a question-and-options prompt as inputs. RSJEV estimates probabilities over those candidates and selects the highest-probability option in one forward pass.
III. METHODOLOGY
- Each labeled sample is formulated from a remote sensing image, an ordered candidate-category list, and the ground-truth category index.The task prompt consists of a classification question and its candidate options.Source: A. Problem Formulation · p. 3
- Candidate descriptions act as semantic conditions processed jointly with the image, and RSJEV estimates a probability distribution over the candidate options.The probabilities are defined conditional on the image, prompt, and candidate set.Source: A. Problem Formulation · p. 3
- The predicted category is the option with the highest probability, enabling classification within the supplied candidate space in one forward pass without autoregressive answer generation.Source: A. Problem Formulation · p. 3
B. RSJEV
RSJEV addresses the repeated input paths used by the original JEV for candidate options by making the decision through one input path and one forward pass.
B. RSJEV
- In the original JEV, the question is expanded into multiple input paths according to the number of candidate options.Source: B. RSJEV · p. 3
- Separately processing those paths repeats image-feature and textual-task-prompt computation, adding computational overhead.Source: B. RSJEV · p. 3
- RSJEV completes the task decision with a single input path in one forward pass.Source: B. RSJEV · p. 3
1) Overall Workflow:
RSJEV processes the image alongside an instruction and candidate categories, then predicts directly from a multimodal answer-slot representation. Its OnePass Decider scores candidate options without autoregressive answer generation.
2) Model Components:
- The multimodal backbone produces contextualized states, and OPD uses the final-layer [RSSC] state conditioned on the image, instruction, and candidate descriptions.Source: 2) Model Components · p. 3
- OPD selects pretrained language-model-head weights for candidate token IDs and normalizes only those candidate scores into probabilities.Source: 2) Model Components · p. 3
- The highest-probability option becomes the predicted category, completing classification in one forward pass without autoregressive answer generation.Source: 2) Model Components · p. 3
1) Overall Workflow:
- Fig. 2 summarizes the one-pass scene-classification workflow, in which the backbone processes the image and a prompt containing the instruction and candidate categories.Source: 1) Overall Workflow · p. 3, Figure 2 · p. 4
IV. EXPERIMENTAL RESULTS AND ANALYSIS
The experiments cover three remote sensing scene-classification benchmarks and compare RSJEV with representative baselines. They also examine OPD across MLLM backbones and compare inference costs with generative MLLMs.
- The evaluation covers UCM, AID, and NWPU-RESISC45, comparing RSJEV's classification performance with representative baselines.Source: §IV · p. 4
- The experiments assess OPD's applicability across different MLLM backbones.Source: §IV · p. 4
- RSJEV is compared with generative MLLM baselines on inference latency, GPU memory consumption, and throughput.Source: §IV · p. 4
A. Dataset Description
The evaluation uses three remote sensing scene-classification datasets under UCM-55, AID-28, and NWPU-28 split settings. The datasets differ in image counts, category counts, and spatial-resolution information reported for UCM and AID.
- UCM-55, AID-28, and NWPU-28 use 50%, 20%, and 20% of images for training, respectively, with the remainder reserved for testing.Source: A. Dataset Description · p. 4
- UCM contains 2,100 aerial images across 21 categories, with 100 images per category and approximately 0.3 m-per-pixel resolution.Source: A. Dataset Description · p. 4
- AID contains 10,000 Google Earth images across 30 categories, with 220–420 images per category and spatial resolutions of 0.5–8 m per pixel.Source: A. Dataset Description · p. 4
- NWPU contains 31,500 RGB images from Google Earth across 45 categories, with 700 images per category.Source: A. Dataset Description · p. 4
B. Implementation Details
Experiments use Qwen3.5-0.8B and train for 10 epochs with AdamW, cross-entropy loss, and Brier score regularization. Evaluation uses precision, recall, F1-score, and overall accuracy.
- Qwen3.5-0.8B is trained for 10 epochs on eight NVIDIA RTX A40 GPUs, using AdamW with a 1 × 10−4 learning rate and cross-entropy loss plus Brier score regularization.Source: B. Implementation Details · p. 4
- Training uses a total batch size of 128, a maximum input length of 1536 tokens, random image flipping, label smoothing of 0.05, and FP32 precision.Source: B. Implementation Details · p. 4
- Evaluation metrics are precision (P), recall (R), F1-score (F1), and overall accuracy (OA).Source: B. Implementation Details · p. 4
C. Comparison Experiments
RSJEV leads the reported comparisons on three remote-sensing scene-classification benchmarks, improves performance across two MLLM backbones, and reduces inference costs relative to evaluated generative MLLMs.
C. Comparison Experiments
- The comparison covers CNN-, Transformer-, Mamba-, vision-language, and multimodal large language model approaches, using pretrained weights or checkpoints fine-tuned for scene classification.The listed baselines include ResNet-101, Swin Transformer, RSMamba, Open-CLIP, and Qwen3-VL.Source: C. Comparison Experiments · p. 4
1) Quantitative Analyses:
- RSJEV posts F1-scores of 97.72% (UCM), 96.30% (AID), and 94.58% (NWPU), beating OSCLIP, Qwen3-VL, and VMamba by 0.39, 0.78, and 0.41 percentage points, respectively.It also achieves the highest precision, recall, and overall accuracy across all three benchmarks.Source: 1) Quantitative Analyses · p. 4, Table I · p. 5
D. Generalizability of OnePass Decider
- OPD improves precision on all three benchmarks for Qwen3.5-0.8B and InternVL3.5-1B, with gains reported across both backbones.The table reports precision (P, %).Source: D. Generalizability of OnePass Decider · p. 5, Table II · p. 5
E. Inference Efficiency Analysis
- On one A40, RSJEV uses 1.68 GB and 102.18 ms per image, with 9.79 FPS versus generative baselines’ 1.31–4.09 FPS.The reported comparison measures GPU memory and latency alongside throughput; RSJEV has the lowest memory use and latency among evaluated methods.Source: E. Inference Efficiency Analysis · p. 5
V. CONCLUSION
The conclusion presents RSJEV as a candidate-conditioned, one-pass framework for remote sensing scene classification. It reports strong classification performance and improved inference efficiency over generative MLLM baselines, with cross-backbone experiments supporting OnePass Decider’s generalizability.
V. CONCLUSION
- RSJEV jointly models visual representations, task instructions, and candidate category semantics for remote sensing scene classification.OnePass Decider estimates candidate probabilities from the final-layer hidden state at the classification answer slot, avoiding autoregressive answer decoding.Source: §V · pp. 5–6
- Experiments report strong classification performance and substantially improved inference efficiency over generative MLLM baselines.Cross-backbone experiments further validate OnePass Decider’s effectiveness and generalizability across MLLM architectures.Source: §V · p. 6
- The conclusion presents JEV-style multimodal discriminative modeling as a potential direction for more efficient and scalable multimodal foundation models.This is framed as a promising direction for remote sensing.Source: §V · p. 6
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