Abstract
Underground crop leave disease classification is the most significant area in the agriculture sector as they are the significant source of carbohydrates for human food. However, a disease-ridden plant could threaten the availability of food for millions of people. Researchers tried to use computer vision (CV) to develop an image classification algorithm that might warn farmers by clicking the images of plant’s leaves to find if the crop is diseased or not. This work develops anew DHCLDC model for underground crop leave disease classification that considers the plants like cassava, potato and groundnut. Here, preprocessing is done by employing median filter, followed by segmentation using Improved U-net (U-Net with nested convolutional block). Further, the features extracted comprise of color features, shape features and improved multi text on (MT) features. Finally, Hybrid classifier (HC) model is developed for DHCLDC, which comprised CNN and LSTM models. The outputs from HC(CNN + LSTM) are then given for improved score level fusion (SLF) from which final detected e are attained. Finally, simulations are done with 3 datasets to show the betterment of HC (CNN + LSTM) based DHCLDC model. The specificity of HC (CNN + LSTM) is high, at 95.41, compared to DBN, NN, RF, KNN, CNN, LSTM, DCNN, and SVM.
Nomenclature
Nomenclature
There exist plants all around the planet. In India, 70% of the populace relies on the agricultural sector, which supports all of the country’s current civilizations. Agriculturalists can choose to produce an extensive variety of fruit and vegetable crops [5,12,19]. Agriculture has historically used techniques including crop rotation, herbicides, irrigation, and fertilizers. Farmers encounter a variety of issues while spotting and recognizing crop illnesses. The inclusion of soil, seed and chemical based methods to agriculture results in better farming system; nonetheless, the complex system of agriculture cannot survive without sensible and careful control of every input. Therefore, progress is needed to produce plants in the right manner [22,25,28]. The main problems that might influence the production of tomato, rice, pepper and potato plants include plant diseases and chemical fertilizers. This also burdens the development of underground crops. Therefore, a more accurate diagnosis and prompt correct crop care are required to avoid them from suffering severe losses as these crops are the major source of carbohydrates that is efficient for the human body. [6,17,18]. Early detection of plant diseases is essential because they can negatively affect animal and human health as well as change the quantity and quality of crops that are produced. Therefore, identifying and categorizing plant diseases is an essential effort [9,15,27]. Determining disease is thus a crucial stage in agriculture.
Advanced methods should be used to solve agricultural issues in order to meet the need for food. The agriculture sectors are concentrating on AI techniques in this area [26,30,31]. Conventional ML techniques have been used to a different of agricultural tasks. Additionally, deep learning (DL) led to important advancements in the study of agriculture. This is because the DL algorithms have the capacity to automatically extract feature [2,8,40]. Among other agricultural issues, correctly classifying plant diseases is essential to increasing the amount and quality of agricultural output while minimizing the need for chemical sprayers like fungicides and herbicides. Therefore, advancing automation in agriculture is a growing area of research [11,37,39]. Due to the similarity in the prevalence of plant diseases, this agricultural duty is challenging. Numerous researches have been done in this area to better categorize plant diseases.
For classifying plant diseases, many typical ML schemes were used. Similar to this, the detection of plant/leaf diseases has also been accomplished using advanced HSI and MSI techniques [3,35,38]. But as DL progressed, a number of cutting-edge architectures, including as VGG, AlexNet, DenseNet, ResNet and Inception-v4, showed promise in classifying plant diseases. Numerous researches [16] have demonstrated the significance of DL-based approaches as opposed to conventional ML techniques. Plant diseases account for about 25% of crop losses, which means that a substantial amount of food that might feed 600 million people is lost. Plant leaf diseases are one of these illnesses that significantly lowers agricultural productivity. The potato crop is of great significance on a national and international scale, as it is a staple crop for both export and local consumption. As a result, treating plant diseases becomes essential for the agriculture industry and economy of our nation. We can increase yields, improve crop quality, and decrease the occurrence of damaged crops by successfully addressing this challenge. By taking this strategy, agriculture advances and the economy is strengthened as well. To overcome all these issues the proposed model is used.
Proposes anew DHCLDC model for underground crop disease classification, where, Improved U-Net model (U-Net with nested convolutional block) is employed for segmentation process.
Extracts color features, shape features and Improved multi texton features from segmented image, which are the essential information to train the hybrid model.
Deploys HC (combining CNN and LSTM) for classification purpose that determines the improved score level fusion for final classification result.
Section 2 describes the reviews of existing DHCLDC approaches. Section 3 describes proposed DHCLDC model & Sect. 4 describes ncolour feature, shape feature and improved MT features. Section 5 explains the hybrid classifiers with improved score level fusion. The outcomes are in 6 and 7 sections.
Literature review
Related works
In 2020, G. Sambasivam and Geoffrey Duncan Opiyo [33] sought to identify cassava infections. Due to class imbalance of dataset, the training of CNNs to attain high precision was very complicated. Class imbalance was an issue that was seen in several fields of ML. However, only little attention was paid to class imbalances. In order to attain an accuracy score of over 93%, this article concentrated on methods using focal loss with DCNN, SMOTE, and class weight. In order to effectively anticipate under represented classes, it was necessary to address high-class imbalance.
In 2022, Yiwei Zhong et al. [41] suggested T-RNet system that, by illustrating global data and reducing the influence of backdrop noise, improved the concern on targeted area for the task of classifying cassava leaf diseases. Additionally, a novel loss operation known as FAMP-Softmax was suggested to help the method obtain drigorous classification limits while battling the dataset’s imbalanced nature related to cassava leaf disease.
Umesh Kumar Lilhore et al. [23] in 2022 presented a thorough learning technique for real time Cassava leaf disease classification using ECNN models. The current CNN model has a high computational cost because to its comprehensive data processing features. The suggested ECNN model used a deep separable convolution layer to fix CNN problems. The number of features and computational overhead were reduced by this feature. The unbalanced images were processed using the suggested ECNN model using a unique block processing feature. The suggested ECNN model made use of a Gamma correction function to address the color segregation problem. The suggested ECNN model made use of worldwide mean election poll with batch normalization to reduce the variable election procedure and to boost computing efficiency.
A very effective CNN design that was ideal for detecting potato illness was proposed by Trong et al. in 2021 [21]. Diseases of plants have a big impact on output, hence crop diseases need to be found and understood. The automated identification of diseased crops is made possible by smart farming employing ML. Disease management and control in real time improved output and lower agricultural losses. The training set’s database was built via image processing. Cross-entropy was employed for model analysis, while Adam was employed as the optimizer. The testing results show that the proposed model has an average reduction in parameter usage of 99.3% and a 99% accuracy rate for diagnosing plant sickness.
Alberta et al. [4] in 2023 presented the ResNet-9 model, which recognized the blight disease status in tomato and potato leaf images that farmers could deploy for their usage. A total of 3,990 data sets were used for training samples. The algorithm was trained with these parameters and tested on the test set, which consisted of 1,331 images. Saliency maps were used to explain the proposed model’s predictions and offer justification for its predictions, allowing for a thorough understanding of the model. In making its predictions, the ResNet-9 model was found to take into account the leaf shape, any diseased regions that were present, and the leaf’s overall green spots. This observation helped us better understand the prediction of the model.
A unique CNN architecture called Efficient Net was suggested in 2021 by Chih Chen et al. [7] employing low bandwidth imaging sensors. For this research, the researcher used negligible-bandwidth, a smaller scale IoT imaging sensors on a farm to periodically notice the cassava leaf images. To correctly categorize and assess the pathology of cassava plants, data enhancement techniques such TTA and cutout, cutmix, and k-fold were used. This study used many simulated trials to categorize and assess the illnesses identified in 5 datasets of cassava leaf samples. Despite some variations in the test set images, this framework was able to produce generally correct classification findings. This article obtained accuracy in classification of 89%, which was better than that of prior research.
Suganya et al. [10] introduced an image processing based method in 2020 that automatically recognized and classified the illnesses affecting groundnut leaves. The H2K approach was recommended for groundnut leaf diseases in order to reliably identify and classify them. The previous literature focused on diseases of leaves that were prevalent to all crops, but this research offered a novel, strong, and ideal technique for identifying and categorizing the diseases affecting groundnut crop. As a result, the H2K technique helped to increase crop output and yield.
In 2022, Mohd Ghazalli et al. [13] deployed image processing techniques to categorize cassava leaves into mosaics and bacteria related ailments. Here, SVM was utilized to identify the cassava leaf based on features like color and texture that were derived. It was discovered that SVM provides accuracy of 87.5%. SVM was therefore shown to be helpful in determining the presence of diseases in cassava leaves.
In 2022, Sabari et al. [32] have deployed a very efficient framework that may be used in the feature extraction stage to categorize various plant and fruit leaf diseases. It employs a modified deep transfer learning method for this purpose. To summarize, we extract characteristics using model engineering (ME). Several support vector machine (SVM) models are used to improve processing speed and feature discrimination. In the training step, the chosen model informs the determination of the radial basis function (RBF) kernel parameters.
In 2022, Kaur et al. [20] have looks into grapevine plant diseases. Leaf blight, black rot, stable, and black measles are the four diseases that grape plants are prone to. Despite several prior study suggestions using machine learning algorithms to identify one or two diseases in grape plant leaves, no one has presented a comprehensive detection of all four illnesses in grape plant leaves. The photos are from the plant village dataset, which is used to retrain the EfficientNet B7 deep architecture via transfer learning. After the transfer learning, a logistic regression technique is used to downsample the gathered features.
Research gaps
The existing research on Cassava disease faces numerous drawbacks, such as reduced recognition rate, high process time, and reduced precision. Some of the difficulties faced in reviewed existing works were as follows: Over fitting issue occurs while employing CNN model. Deep networks typically needs long training time, thus makes itnot capable for applications in real world. In, ECNN, higher processing time is challenging issue. In order to confirm symptoms and complement images, PCR tests can be required. InceptionV3 takes a long time and a lot of processing power. CNN model has poor generalization capability. Separable Convolutions UNet model requires ineffective ensemble of schemes of varied depths. In SVM model, there was a long training time for large datasets. Table 2 shows the review on the existing models.
Reviews on existing models on plant disease classification
Reviews on existing models on plant disease classification
The developed DHCLDC model for underground crop disease classificationis given below. This work considers three crops like cassava, potato and groundnut. The initial step is pre-processing is carried out by deploying median filter that eliminates the unwanted noise. Then, deploys Improved U-net based segmentation model, that is, U-Net with nested convolutional block that including the convolutional and dropout layer in the nested architecture. Features like colour feature, shape feature and improved multi text on features are extracted. Finally, HC (CNN and LSTM) is deployed for classification of underground crop disease by training the extracted feature set.The classification outcome is obtained by the improved SLF. The adopted DHCLDC model for underground crops is represented in Fig. 1.

Diagrammatic demonstration of DHCLDC model for underground crops.
Pre-processing aims to improve the image data by reducing distortions and helps to enhance certain components that are essential for further processing.
MF is used for reducing noise and it effectively preserves edges. ‘Salt and pepper’ type noise is particularly well-admitted by this method. The term “Window” in MF refers to the neighborhood pattern, which moves pixel by pixel over the whole image. The median is evaluated by placing the pixel in the middle (median) of every value of a pixel from the window and then sorting them all into numerical order. This work deploys CV2. Median Blur () to compute the median of all pixels under the kernel window and then the central value is replaced with median value.
Then, improved U-Net scheme is used to segment the processed image,
Improved U-Net (U-Net with nested convolutional block) for segmentation
U-Net is a network with training technique that makes better use of labeled data through data augmentation, enabling it to provide effective results with fewer samples. The loss function of U-Net model, however, has a number of drawbacks [34]. The U-Net model has advantages were carried over into an enhanced U-Net, which also made several additional improvements. Improved U Net with a novel loss function combines new elements including skip route and deep supervision. It corrects the data imbalance issue in image segmentation and produced effective segmentation outcomes [34]. Also, the architecture is improved by adding the nested convolutional block with the combination of convolutional layer and dropout layer, and is illustrated in Fig. 2.
In traditional U Net, BCE is deployed as loss function as exposed in Eq. (1), in which, N indicate sample count,
In enhanced UNet, rather than BCE loss, we have combined the weighted BCE loss with dice loss as provided in Eq. (2), where, ψ indicates tuning parameter, ψ can be used to tune FP and FN, e.g. If we set
The enhanced segmented image is implied by

Illustration of improved U-Net (U-Net with nested convolutional block) for segmentation.
Extracting features enhances the efficacy of ML by eliminating unwanted and superfluous data by reducing the noise. From
Improved MT features
In MTH oriented image retrieving method [24], orientation of texture should be recognized for text on analysis. Orientation of texture could also be deployed for estimating the textured image shape. Using specific gradient operators in both vertical and horizontal orientations on a greyscale image, 2 gradient images, signified as
The gradients in χ and κ orientations are signified by 2 vectors
The angle among b and a is modeled as in Eq. (8).
An alternative orientation strategy is used for colored images, as shown in Eq. (9).
As per improved MT, the orientation is modeled as in Eq. (10), where
Shape features
The shape features considered are area, perimeter, approximation and convexity. The input image is transformed to grey scale image prior to the extraction of shape features. The shape features are implied as
Colour features
The color features like mean, histogram, standard deviation, and median, frequency of maximal color and frequency of minimal color are extracted. These features are extracted for each B, G and R channels separately. The color features are implied as
The modified colour feature, shape feature and improved MT features are entirely implied by
HybridClassifiers with improved score level fusion
CNN
The features
The pooling lowers the number of parameters by stacking down samples of a specified input size. In an input area, max pooling – the most popular method – yields the highest value.
No need for human oversight is necessary. Incredibly precise in both image identification and categorization. Sharing of weight. Cuts down on computation. Applies the same knowledge to every location in an image. The capacity to manage big datasets. Learning in hierarchies.
LSTM
The features
Here,
t = time
For time series applications, LSTM are superior than basic RNNs in a number of ways.
They are superior to RNNs at capturing long-term dependencies since RNNs have a tendency to forget about remote previous inputs.
For time series with long-term cycles or patterns, like meteorological data or economic indicators, this is crucial. Table 3 represents the classifier hyperparameteres.
Hyper parameters of classifiers
Hyper parameters of classifiers
The improved SLF is performed by getting MSE from CNN and LSTM classifiers. The similarity between the input and template biometric feature vectors is gauged by the match score. Fusion is referred to as occurring at the match score level when the combined match scores from various biometric matchers lead to a final recognition determination. This is sometimes referred to as measurement-or confidence-level-level fusion. In addition to the unprocessed data and feature vectors, the match scores hold the most comprehensive information regarding the input pattern. Additionally, combining and accessing the scores produced by several biometric matchers is not too difficult.
The predicted scores of CNN denoted by
Then, the mean of CNN and LSTM are determined as shown in Eq. (23) and (24).
The deviation of CNN and LSTM are computed as in Eq. (25) and (26).
Thus, list of S and MSE error is obtained as shown in Eq. (27) and (28).
Subsequently, get the minimum MSE error from both CNN and LSTM [36]. Based on minimum index, get the weight value, e.g. if
Thus, the cassava dataset outcomes are classified as Healthy, CBSD, CBB, CMD and CGM. The potato dataset outcomes are classified as healthy, Early blight, Late blight. The groundnut dataset outcomes are classified as early leaf spot, early rust, healthy leaf, late leaf spot, nutrition deficiency and rust.
Results and discussions
Experimental set up
The HC (CNN + LSTM) model for DHCLDC of underground crops was done in Python. Here, the extant schemes like DBN, NN, RF, KNN, CNN, LSTM, DCNN [33] and SVM [13] models were compared over presented HC (CNN + LSTM) method. The following performance measures are used to analyze plant disease detection.
Accuracy is measured using a set of measurements and their real results. Equation (31) establishes the computed accuracy formula, in which
The percentage of correctly classified instances serves as a proxy for precision. It states this in Eq. (32).
The probability of a positive test result is described by sensitivity, which only includes positive true values. The expression for it is Eq. (33).
Specificity is the probability of just having actual negative values. Equation (34) displays this equation
It’s defined as the possibility that a test will overlook a real positive. Equation (35) is explained.
Regardless of whether the test is a machine learning model, its false positive rate (FPR) serves as a gauge of its effectiveness in Eq. (36)
The predicted ratio of the total number of positive classifiers to the total number of erroneous positive classifications is known as the false positive rate, or FDR. It is described in Eq. (37).
To evaluate the accuracy results, the F-measure is employed. The Eq. (38) represents it.
Using a contingency matrices technique, the Matthews correlation coefficient is used to calculate the Pearson coefficient for the product-moment correlation between real and expected data. This alternative metric is unrelated to the problem of imbalanced datasets. It can be seen in Eq. (39).
Equation (40) denotes negative predictive value.
Simulation setup
Simulation setup
The data was gathered from [1,29] and [14] for Cassava, Potato and Groundnut crops that were described here as dataset 1, 2 and 3 respectively. Cassava Dataset: Only when the test is turned in for scoring will your notebook get access to the entire collection of test images. The test set should contain about fifteen thousand photos. Farmers may find a quick automated turnaround to be particularly helpful in certain situations where burning the contaminated plants is the primary treatment to stop the disease from spreading. Potato dataset: 1500 picture files from three distinct classes – healthy, late blight, and early blight – make up this dataset. The groundnut dataset allowed us to count the number of leaves in a particular picture. The dataset is a component of a full-featured mobile machine learning tool that assesses the degree of groundnut plant disease. The dataset includes XML files with labels for the photos. Figure 3 exposes the sample images.

Sample images for datasets a) 1 b) 2 and c) 3.
The evaluation of the HC (CNN + LSTM) over DBN, NN, RF, KNN, CNN, LSTM, DCNN [33] and SVM [13] is exposed in Fig. 4–12 for three datasets (Cassava, Potato and Groundnut datasets). For every metric taken into consideration, the developed HC (CNN + LSTM) has shown improved values. Regarding the Cassava dataset, the HC (CNN + LSTM) accuracy is increasing from the 60th to the 90th LP. The accuracy of HC (CNN + LSTM) is 88.175 at the 60th LP, 92.46 at the 70th LP, 94.69 at the 80th LP, and 95.548 at the 90th LP. This shows that, better performance is obtained when LP is 90. The FNR of HC (CNN + LSTM) in the potato dataset decreases from the 60th to the 90th LP. The specificity of DBN, NN, RF, KNN, CNN, LSTM, DCNN [33] and SVM [13] is 90.3, 85.86, 86.65, 93.65, 93.73, 90.95, 93.34 and 93.30 respectively for dataset 3. When compared to DBN, NN, RF, KNN, CNN, LSTM, DCNN [33] and SVM [13], the specificity of HC (CNN + LSTM) is high around 95.41. Better results are obtained because a modified Unet model with increased multi-texon characteristics is used. Furthermore, improved SLF with hybrid CNN and LSTM models also contributed to better plant leaf classification. As a result, the suggested model’s superiority over the other models in use is demonstrated.

Examination on HC (CNN + LSTM) method for DHCLDC of underground crops for a) specificity b) sensitivity c) accuracy d) precision for dataset 1.

Analysis of HC (CNN + LSTM) model for DHCLDC of underground crops for a) FNR b) FPR for dataset 1.

Analysis of HC (CNN + LSTM) model for DHCLDC of underground crops for a) NPV b) MCC and (c) F measure for dataset 1.

Analysis of HC (CNN + LSTM)method for DHCLDC of underground crops for a) specificity b) sensitivity c) accuracy d) precision for dataset 2.

Analysis of HC (CNN + LSTM) model for DHCLDC of underground crops for a) FNR b) FPR for dataset 2.

Analysis of HC (CNN + LSTM) model for DHCLDC of underground crops for a) NPV b) MCC and (c) F measure for dataset 2.

Analysis of HC (CNN + LSTM) model for DHCLDC of underground crops for a) specificity b) sensitivity c) accuracy d) precision for dataset 3.

Analysis of HC (CNN + LSTM) model for DHCLDC of underground crops for a) FNR b) FPR for dataset 3.

Analysis of HC (CNN + LSTM) model for DHCLDC of underground crops for a) NPV b) MCC and (c) F measure for dataset 3.
The ablation analysis for HC (CNN + LSTM) over suggested with existing U-Net, proposed with existing multitex on, and suggested with existing SLF is shown in Table 5–7. The DHCLDC scheme’s net present value (NPV) while utilizing the HC (CNN + LSTM) technique is 0.912773; in contrast, the NPV when utilizing the proposed U Net, extant multitex, and extant SLF approaches are 0.781332, 0.785736, and 0.903983. Furthermore, the precision obtained with the HC (CNN + LSTM) technique is 0.932977, whereas the precision obtained with the HC (CNN + LSTM) technique with the existing U Net, the proposed multitex on, and the proposed SLF are 0.784864, 0.788046, and 0.908209.Better results are obtained by using an updated U net model with enhanced multi-texon characteristics. Additionally, updated SLF hybrid CNN and LSTM models helped to improve plant leaf classification.
Statistical analysis
Table 8 shows accuracy on HC (CNN + LSTM)over DBN, NN, RF, KNN, CNN, LSTM, DCNN [33] and SVM [13]. The HC (CNN + LSTM) achieved the greater accuracy of 0.955484 for maximum case, while DBN, NN, RF, KNN, CNN, LSTM, DCNN [33] and SVM [13] have achieved greater accuracy of 0.92758, 0.826896, 0.893675, 0.917395, 0.900547, 0.934243, 0.914368 and 0.926304 for dataset 1. The median case using HC (CNN + LSTM) is0.93208, while, DBN, NN, RF, KNN, CNN, LSTM, DCNN [33] and SVM [13]gained less accuracy of 0.880981, 0.776491, 0.859265, 0.880863, 0.885786, 0.870687, 0.875057 and 0.874353. Improved U net model with expanded multi-texon characteristics yields better outcomes. Additionally, improved SLF hybrid CNN and LSTM models produced superior plant leaf categorization.
Ablation study on developedDHCLDC approach for dataset 1
Ablation study on developedDHCLDC approach for dataset 1
Ablation study on developed DHCLDC approach for dataset 2
Ablation study on developed DHCLDC approach for dataset 3
Statistical analysis onaccuracy for DHCLDC approach
Table 9 reveals the evaluation on segmentation accuracy, Jaccard and Dice scores. The evaluation is done on K means, FCM and conventional U-net schemes over improved U-net segmentation method. For 3 datasets, the segmentation accuracy, Jaccard and Dice scores attained high values for improved U-net approach.
Analysis on segmentation accuracy and Jaccard, Dice scores
Analysis on segmentation accuracy and Jaccard, Dice scores
Plant diseases are detectable from the start. It is possible to keep disease outbreaks at a strategic distance. Through GSM interface, information about the plants and framework will be recommended to the client. Depending on our needs, this can be set to take any form of leave. This can be changed to accommodate any kind of leaf depending on our requirement. When a plant disease detection system detects common irregularities on the leaves, like mold or burning, it can function as a universal detector.
Conclusion
This paper proposes a novel DHCLDC technique for underground crops. In this, preprocessing was done via deploying median filter. Then, improved U-net model was carried out for segmentation process. Moreover, the features extracted comprised of color features, shape features and improved multi texton features. Finally, HC model was suggested for DHCLDC that combines CNN and LSTM models. The outputs from HC (CNN + LSTM) were then subjected to improved SLF from which final detected outcomes were attained. Regarding the Cassava dataset, the HC (CNN + LSTM) accuracy was increasing from the 60th to the 90th LP. In the 60th LP, the HC (CNN + LSTM) accuracy was 88.175; in the 70th LP, it was 92.46; in the 80th LP, it was 94.69; and in the 90th LP, it was 95.548. This demonstrates that when LP is 90, higher performance was achieved. Additionally, the entire leaf area affected by the infection is identified by this research. Early plant disease identification is an extremely difficult endeavor in existing methods. But, this system will detect the plant disease earlier. The limitation of the suggested approach is processing time is not taken into account. We intended to apply the same technique to smartphones, making it simple for farmers to receive results within the allotted time. Future research on processing times must be conducted.
