Tag Archives: geojson

Digital Histology, Python, Tools

Serialization and storage of GeoJson in Digital Pathology

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GeoJSON, a widely used format based on JSON (JavaScript Object Notation), is specifically designed for encoding a variety of geographic data structures. This versatile format excels in representing simple geographical features, such as points, lines, and polygons, along with their non-spatial attributes. In the realm of digital pathology, GeoJSON has emerged as a common format for storing annotations, enabling precise documentation of regions of interest, cellular structures, and other critical details within pathology images. The popularity of GeoJSON in this field is bolstered by its broad support across numerous tools (e.g., Qupath) and thus facilitates seamless integration and analysis in digital pathology workflows.

Despite its widespread adoption, there are several open questions regarding the efficient use of GeoJSON that can significantly impact performance. One key concern is the best method for storing GeoJSON in a compressed format to minimize storage requirements while preserving the integrity of the data. Efficient compression techniques are crucial, especially when dealing with large-scale pathology datasets.

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Deep Learning, Digital Histology

Using QuPath To Help Identify An Optimal Threshold For A Deep Or Machine Learning Classifier

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Digital pathology projects often require assigning a class to cells/objects. For example, you may have a segmentation of cells/glomeruli/tubules and want to identify the ones which are lymphocytes/sclerotic/distal. This classification process can be done using machine or deep learning classifiers by supplying the object of question and receiving an output score which indicates the likelihood that that particular object is of that particular type.

This blog post will demonstrate an efficient way of using QuPath to help find the ideal likelihood threshold for your classifier.

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Deep Learning, Digital Histology, Uncategorized

Exporting and re-importing annotations from QuPath for usage in machine learning

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Update-Nov 2020: Code has now been placed in github which enables the reading and writing of compressed geojson files at all stages of the process described below. Compression reduces the file size by approximately 93% : )

QuPath is a digital pathology tool that has become especially popular because it is both easy to use to and supports a large number of different whole slide image (WSI) file formats. QuPath is also able to perform a number of relevant analytical functions with a few mouse clicks. Of interest in this blog post is mentioning that the pathologists we tend to work with are either already familiar with QuPath, or find it easier to learn versus other tools. As a result, QuPath has become a goto tool for us for both the creation, and review of, annotations and outputs created by our algorithms.

Here we introduce a robust method using GeoJSON for exporting annotations (or cell objects) from QuPath, importing them into python as shapely objects, operating upon them, and then re-importing a modified version of them back into QuPath for downstream usage or review. As an example use case we will be looking at computationally identifying lymphocytes in WSIs of melanoma metastases using a deep learning classifier.

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