Slice

As explained in Deep Learning with PyTorch, Second Edition

A two-dimensional cross-section extracted from a CT scan for segmentation training or visualization.

A slice is a two-dimensional cross-section extracted from a volumetric CT scan. Treating each slice as a separate image lets a 2D model such as SAM segment suspected nodules while keeping results easier to visualize. section 15.6.1 section 15.1

A CT slice supports the segmentation workflow by providing:

• A spatial position within the larger CT volume. section 15.6.1
• A 2D image that can be paired with a nodule point or segmentation mask. section 15.6.2
• Training and validation data for fine-tuning a segmentation model. section 15.6.1 section 15.1
• A cached artifact that avoids repeatedly reading and parsing the full CT volume. section 15.6.2

Extracting one slice

The extraction code converts an XYZ center into image coordinates, selects one axis of the CT array, and returns a two-dimensional tensor. A retrieved example has shape torch.Size([512, 512]) and can be plotted with its candidate nodule point. section 15.6.2

Figure 15.10 Lung CT scan slice with segmentation mask over nodule

View a lung CT slice with a segmentation mask over a nodule. section 15.6.1

How Deep Learning with PyTorch, Second Edition covers it

How deep it goes

Explains extraction, coordinates, dimensions, visualization, caching, and spacing tradeoffs, but stops short of full 3D processing.

Examples

Uses lung CT slices, candidate nodule points, segmentation masks, coordinate-based extraction, and 512-by-512 tensors.

What it assumes

Assumes volumetric CT data, candidate coordinates, and basic dataset handling while teaching how to obtain a 2D slice.

What you can do after

Build it from scratch by extracting, inspecting, plotting, caching, and pairing CT slices with masks for segmentation training.

How it connects

Connects CT scans with segmentation, masks, datasets, SAM, and classification.

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Related concepts

• computed tomographypart of · Computed tomography is an imaging technique that uses multiple X-ray measurements and computational reconstruction to produce cross-sectional or volumetric images.
• digital imageequivalent to · A digital image is visual content encoded as data, typically as a two-dimensional arrangement of pixels or equivalent visual elements.
• slicinguses · Slicing selects or partitions a portion of an indexed sequence or multidimensional array, often along specified indices or dimensions.

This explainer was generated by Manning's knowledge graph from the text of Deep Learning with PyTorch, Second Edition. The section links point to the parts of the book it draws on.