Computer Vision-based, realtime, abnormal event recognition
The primary task of this system is to detect fines in the oversize conveyor stream. Ore is separated by size through the screenhouse using wet screens. The oversize stream should ideally contain only larger materials, while the fines are separated out. However, screen overflow occurs when these fines mistakenly end up in the oversize stream. The computer vision system continuously analyses the video stream over the conveyor in real-time using AI and machine learning algorithms to detect these overflow events.
The AI algorithm is trained to identify characteristics of fines, such as size, shape, and color. When an anomaly, like an excessive presence of fines in the oversize stream, is detected, the system recognises this as a screen overflow and alerts the Process Control System. Upon detecting screen overflow, the system can alert operators, or in more advanced setups, automatically initiate corrective measures like lowering feedrate onto the screens or changing the motor speeds for the vibrating screens.
Over time, the system can further be trained to understand patterns in screen overflow incidents. This analysis can inform preventive maintenance, process optimisation, and even design improvements in equipment.
Increased Efficiency
By quickly identifying and correcting screen overflows, the Minealytics Screen Overflow Detection System can help maintain the efficiency of the sorting process. This leads to better utilisation of the conveyor and screening equipment, ensuring that materials are processed at optimal rates.
Improved Product Quality
Accurate detection of screen overflow helps in maintaining the quality of the separated materials. Ensuring that only appropriately sized material is processed in each stream leads to higher quality end-products.
Reduced Equipment Wear and Tear
Overflows can cause undue stress on screening equipment, leading to increased wear and tear. Timely detection and correction of these overflows can extend the life of the equipment and reduce maintenance costs.
Decreased Downtime
By preventing the build-up of incorrect material sizes in processing equipment, these systems can reduce the frequency and duration of downtime needed for maintenance and cleaning.
Enhanced Safety
Automated detection reduces the need for manual monitoring, thereby minimizing the exposure of workers to potential hazards in the processing area.
Cost Savings
Efficient processing and reduced downtime lead to significant cost savings. This includes lower labor costs (due to reduced need for manual monitoring and sorting), decreased maintenance costs, and improved overall operational efficiency.
Data-Driven Insights
These systems can collect and analyze data over time, providing insights into the frequency and causes of screen overflows. This information can be used to improve the screening process, design better equipment, and make more informed operational decisions.
Environmental Impact
Efficient processing and reduced waste contribute to more sustainable mining practices, which is increasingly important in today's environmentally conscious market.
Regulatory Compliance
In some cases, ensuring material is correctly sorted and processed can be a regulatory requirement. Screen overflow detection helps in maintaining compliance with such regulations.
Flexibility and Scalability
Advanced screen overflow detection systems can be adapted to different types of materials and processing environments, making them a versatile solution for various mining operations.
Designing a Convolutional Neural Network (CNN) for binary classification to recognise overflown events on a mining conveyor involves several steps. This process includes data collection and preparation, architecture design, training, and deployment. Here's a detailed breakdown:
1. Data Collection and Preparation
Collecting Images: Capture a large number of images from the conveyor showing both normal operation and overflow events. Ensure varied lighting and environmental conditions are represented.
Labeling: Annotate these images, labeling them as 'Normal' or 'Overflow'. This step is critical for supervised learning.
Preprocessing: Standardise the images (resize, normalize pixel values, etc.). Consider augmenting the data set with techniques like rotation, flipping, or adding noise to improve the model's robustness.
2. Architecture Design
Input Layer: Design the input layer to accept the standardised image size.
Convolutional Layers: These layers extract features from the images. Use multiple convolutional layers, with each layer detecting more complex features. Include activation functions like ReLU to introduce non-linearity.
Pooling Layers: Following convolutional layers with pooling layers (like max pooling) reduces the spatial size of the representation, lowering the number of parameters and computation in the network.
Fully Connected Layers: After several convolutional and pooling layers, add one or more fully connected layers for classification. These layers use the features extracted by previous layers to determine the image's class.
Output Layer: Since it's a binary classification (Normal or Overflow), the output layer should have a single neuron with a sigmoid activation function, which outputs a value between 0 and 1, indicating the probability of an overflow event.
3. Training the CNN
Loss Function: Use a binary cross-entropy loss function, which is suitable for binary classification problems.
Optimizer: Choose an optimizer like Adam or SGD for adjusting weights during training.
Validation Set: Split your data into training, validation, and test sets. The validation set helps in tuning the hyperparameters and avoiding overfitting.
Training: Train the network using the training dataset. Monitor the performance on the validation set to adjust parameters like learning rate, number of epochs, or layers.
4. Evaluation and Tuning
Performance Metrics: Evaluate the model using metrics like accuracy, precision, recall, and F1 score.
Tuning: Based on the evaluation, tune the model by adjusting its architecture, hyperparameters, or training data.
Overfitting Check: Ensure that the model is not overfitting the training data. Techniques like dropout, regularization, or augmenting more data can help.
5. Deployment
Integration: Integrate the trained model into the conveyor system for real-time analysis.
Monitoring and Updating: Continuously monitor the model's performance in real-world conditions and update or retrain as necessary.
Challenges and Considerations
Varying Conditions: The model should be robust to variations in lighting, material properties, and conveyor speed.
Real-time Processing: The CNN must process images quickly enough to allow real-time detection and response to overflown events.
Resource Constraints: Consider the computational resources available, as more complex models require more processing power.