The agricultural industry in the world is changing at an alarming rate as it adopts new and modern technologies to help guarantee the crop health, high productivity and global food security. As the population is demanding sustainable methods of farming, the demand of diagnostic methods that are rapid, accurate and non-destructive is on the increase.
Tomato is one of the most popular and economical vegetables in the world among the major horticultural crops. But the Bacterial leaf spot (BLS) is a serious menace to tomato production that it can propagate rapidly in favourable environmental conditions and result into massive loss of yield (
Abdulridha et al., 2020,
Sreedevi et al., 2023). Timely and accurate diagnosis of BLS is thus important in reducing economic losses and ensuring massive loss in crops. Conventionally, experts, simple spectral vegetation indices and statistical analysis of reflectance data have been used as conventional methods to diagnose tomato diseases due to visual inspection. Although these methods are simple and inexpensive, they are usually not sensitive to the biochemical and structural variations that take place in the initial stages of infection. Over the last few years, hyperspectral imaging (HSI) has become a very promising agent in detecting plant diseases due to its ability to record spectral details in hundreds of narrow wavelength bands
(Barreto et al., 2023, Duhan et al., 2025).
Zhang et al., (2024); Krishnan and Kumar (2023). HSI allows automated identification of compound spectral-spatial patterns of plant stress and disease, when combined with deep learning (DL). Many studies have examined the different analytical models of identifying plant disease based on hyperspectral data, but each offers distinct advantages and limitations (
Duhan et al., 2025;
Xie et al., (2022) proposed an early benchmark study with statistical band reduction based on Successive Projections Algorithm (SPA) for wavelength selection with an Extreme Learning Machine (ELM) classifier. Their approach proved useful in dimensionality reduction and enhanced classification. But it was very sensitive to manually chosen subsets of spectral and poor in scalability and flexibility. On the same note,
Zhou et al., (2025) proved that it is possible to detect tomato leaf diseases early with the help of classical machine learning. They used Gaussian filtering as the method of reducing spectral noise and used optimization algorithms to select the discriminative wavelengths to use in SVM classification with an accuracy of 97%.
The paper has pointed out the usefulness and intuitiveness of spectral band optimization. Nevertheless, DMLP goes further than the dimensionality reduction methods like PCA by including spectral-spatial fusion and multiple-branch receptive field expansion. The current structure is more focused on computational efficiency and real-time spatial flexibility of hyperspectral diagnostics as compared with
Zhou et al., (2025) who focused their attention on environmental stability and simplicity.
Reis et al., (2024) investigated the effect of nitrogen fertilization on the spectral detectability of tomatoes with bacterial leaf blight. The data collected by them showed that nutrient stress alters spectral responses, which impact disease classification. They improved predictive performance with vegetation indices like NDVI with combination with other spectral characteristics. They, however, used methodology that involved multi-stage calculations and several data fusion steps. Conversely, the perceptron-based framework suggested makes processing simpler in the sense that implicit spectral-spatial fusion is carried out in a single unified network, which makes real-time implementation feasible without the need to run complex preprocessing pipelines.
Shirly (2025) was interested in measuring severity of diseases by the changes in spectral signatures. Although their hybrid architecture was quite useful in tracking disease evolution with time, it was based on distinct severity mapping modules, which could not be easily combined into a simpler classification architecture. The DMLPFFN on the other hand is planned to give quick and precise projections within a unified model framework without the necessity to have additional computational units. Even though some researchers recorded high results with the help of DBO and BiLSTM models separately, the DMLP optimizes the incorporation of spatial features at the initial stages of detection that is critical to timely intervention
(Zhou et al., 2025).
There are several other works, which have led to the changing environment of detection of hyperspectral diseases. Custom spectral features attracted
(Guo et al., (2023) who integrated the play of Random Forest (RF) and Partial Least Squares Regression (PLSR). Nevertheless, they could not generalize because they used handcrafted features.
Mahlein et al., (2018) combined spectral reflectance and texture descriptors to enhance resiliency, however, at the expense of preprocessing.
Zhang et al., (2024), investigated multi-temporal tracking, which allows tracking the disease development on repeating early foliar bacterial infections in tomato leaves for non-invasive hyperspectral insights. Such methods are more effective, but they need more than one data capture.
Xu et al., (2026). also optimized the choice of bands to minimize the computational cost but could have lost subtle biochemical signals during the process. The DMLPFFN tackles those issues by relying on PCA-based compression to maintain the variance but also expand the spectral-spatial representations.
Wei et al., (2025), enhanced the accuracy of classification using the combination of hyperspectral and RGB using optical imaging but added complexity to hardware.
(Xu et al., 2022) proposed spectral attention networks that did not only improve the emphasis on wavelengths but also added to the number of computations. Multi-branch perceptron the lightweight multi-branch perceptron architecture is an efficient feature weighting architecture which uses no costly attention mechanisms.
More recent models have tried new architectures including ResNet variants, transformers, GAN-based augmentation and multimodal fusion network. Although such systems can be accurate (more than 95%), they usually have deep backbones that require millions of parameters and complex fusion blocks, making the deployment of edges difficult. To overcome these drawbacks, the DMLPFFN is a multi-branch spectral-spatial fusion implementation of lightweight perceptron blocks, which is highly expressive at low computational cost. Hyperspectral tomato dataset provided by USDA
Yadav et al. (2024) in this study was also well pre-processed to guarantee uniformity and strength. Water absorption bands were eliminated and band counts (
e.g. 168 and 300 bands) were reduced to 128 components with Principal Component Analysis (PCA) to 128 components. The last data set was made up of around 12,740 samples that were arranged in a format of 9x9 Spectro-spatial patches with a stride of 4. In order to ensure an equal representation, data were partitioned into stratified 70/15/15 train, validation and test split. To overcome the imbalance in classes, weighted loss and balanced sampling were used in training (
Acheraiou et al., 2025;
Reddy, 2026). The proposed dual multi-layer perceptron feature fusion network is a joint feature learning algorithm that is trained on full spectral-spatial patches. This removes the need to use manually made wavelength selection and increases feature richness. Its architecture includes 4D patch tensors of shape (N,128,9,9) to combine the features. Instead of using deep convolutional stacks or recurrent layers, it has a multi-branch architecture, which has low-, middle- and high-level feature pathways. A Local Perceptron feature module which has dilated convolutions is an efficient expansion of the spatial receptive field. This architectural design allows the spectral and spatial features to be fused through element-wise addition, thus satisfying the need for greater efficiency in early-stage detection and better computational scalability when compared with previous methods.
After the introduction, Section 2 presents the suggested methodology of early disease detection of tomato bacterial leaf spot disease with the help of the USDA hyperspectral dataset and includes a block diagram of the research process along with explanations of evaluation measures. Section 3 addresses the findings of the experiments and their comparison with the current approaches. Lastly, the conclusion of Section 4 sums up the study by stating the opportunities of improving the work and extending it in the future.