images enhances the model's overall disability under
varying conditions and ensures our model performs
optimally in real-world environments.
3.2 Preprocessing
Preprocessing of the images is an essential step to
improve visibility and model strength. Satellite
images tend to be plagued by noise, non-uniform
illumination, and distortion caused by atmospheric
effects. These would lower the accuracy of our model
if not corrected. To overcome such issues, we
undertake a series of preprocessing steps that are
outlined below:
Contrast Adjustment: Increasing contrast of the
images to make garbage more visible among the
surrounding waters. This feature is particularly
beneficial when the plastics are blended together with
the natural ocean environment.
Noise Reduction: Using filters like Gaussian blur
and median filtering to remove irrelevant noise and
highlight debris. Noise reduction makes sure that the
model is not confused by slight distortions to be
considered as marine debris.
Histogram Equalization: Re-scaling image
intensities to equate variations caused by illumination
conditions, cloud shadows, and sun glint over water
surfaces. Histogram equalization allows the creation
of a more balanced dataset in which debris features
are more accurately represented.
Cloud Masking: Since satellite images are mostly
covered with clouds that obstruct visibility, we apply
cloud detection algorithms to eliminate unusable
portions of images. Cloud-affected pixel removal
prevents misclassification and increases the accuracy
of our model.
Apart from that, we normalize the images so that
the distributions of the pixel intensities are uniform,
and that reduces the model's sensitivity towards
environmental variations. Through these
preprocessing techniques, we significantly improve
the quality of training data so that the model is able to
focus on useful features.
3.3 Model Architecture
We employ a CNN-based segmentation model to
accurately detect debris regions in satellite images.
Our approach tests a wide range of deep learning
architectures well chosen to trade off accuracy,
computational expense, and insensitivity to various
environments. The architectures we test are:
U-Net: A fully convolutional network (FCN)
specifically for pixel-wise segmentation. U-Net
performs very well for detecting fine-grained details
in images and is especially useful in separating small
floating trash from water.
DeepLabV3: A more sophisticated segmentation
model that uses a spatial pyramid pooling (ASPP) to
integrate multi scale contextual information.
DeepLabV3 is useful in studying large-scale marine
litter aggregations since it can identify small- and
large-scale litter structures.
SSD ResNet101: A high-performance object
detection model that provides quick detection with no
accuracy compromise. SSD performs extremely well
in real-time detection of marine trash if employed in
conjunction with automated monitoring systems.
All of these architectures are optimized to attain
optimal accuracy, reduce computational cost, and
generalize efficaciously to various marine
environments. Selection of models is determined
based on fundamental parameters like precision,
recall, F1-score, and computational cost. Although U-
Net and DeepLabV3 are of higher segmentation
accuracy, SSD ResNet101 is optimized for real-time
performance-based systems.
To further improve the performance of the model,
we use transfer learning through pre-initialization of
the networks with pre-trained weights from large
datasets. This allows the model to learn higher-level
visual representations, which further improve its
performance in detecting debris even with limited
training data.
The second vital enhancement is data
augmentation, which introduces variations such as
random flipping, rotation, and brightness
adjustments. Such techniques prevent over fitting and
enable the model to generalize suitably under diverse
environmental conditions. In summary, our
segmentation approach based on CNN provides a
time-efficient method of detecting, classifying, and
segmenting marine debris from satellite images. By
leveraging the latest deep networks, we achieve high
accuracy while maintaining scalability to large-scale
marine debris monitoring.
3.4 Evaluation
To assess the performance of our deep learning model
for marine litter detection, we use different
performance metrics like precision, recall, F1-score,
and mean average precision (mAP). These metrics
enable our model to detect marine debris accurately
and minimize false positives and false negatives.
1. Precision and Recall: Precision is the number of
correctly classified instances of debris over the total
number of predicted regions of debris, and recall is