ROI: Measurements

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ROI: Measurements#

ROI objects define regions of interest for image measurements. The ROI is a core element in analyzer analysis and is required for analyzer construction. For analysis that does not require an ROI, a placeholder NoROI is used. In particular, LineROI is used to extract line profiles from images, and area ROI classes are used to extract area information or perform other types of analysis.

The ROI class can be constructed using an ImageJ ROI file or manually specified parameters.

Example#

import numpy as np

from pyleem.roi import LineROI, RectROI

image = np.arange(10000).reshape(100, 100)

# Line ROI: extract a line profile and intensity statistics.
line_roi = LineROI(src=(10, 5), dst=(10, 80), linewidth=3)
line_measurement = line_roi.measure(image)
profile = line_measurement.profile

# Area ROI: measure intensity statistics inside a rectangle.
area_roi = RectROI(top=20, left=30, bottom=50, right=60)
area_measurement = area_roi.measure(image)
mean_intensity = area_measurement.mean

# Save and reload ImageJ ROI files.
line_roi.tofile("line.roi")
area_roi.tofile("area.roi")
line_roi = LineROI(roi_file="line.roi")

  • ROI API: For custom ROI implementations.

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