Source code for dclab.features.bright

# -*- coding: utf-8 -*-
Computation of mean and standard deviation of grayscale values inside the
RT-DC event image mask.
from __future__ import division, print_function, unicode_literals

import numpy as np

[docs]def get_bright(mask, image, ret_data="avg,sd"): """Compute avg and/or std of the event brightness The event brightness is defined by the gray-scale values of the image data within the event mask area. Parameters ---------- mask: ndarray or list of ndarrays of shape (M,N) and dtype bool The mask values, True where the event is located in `image`. image: ndarray or list of ndarrays of shape (M,N) A 2D array that holds the image in form of grayscale values of an event. ret_data: str A comma-separated list of metrices to compute - "avg": compute the average - "sd": compute the standard deviation Selected metrics are returned in alphabetical order. Returns ------- bright_avg: float or ndarray of size N Average image data within the contour bright_std: float or ndarray of size N Standard deviation of image data within the contour """ # This method is based on a pull request by Maik Herbig. ret_avg = "avg" in ret_data ret_std = "sd" in ret_data if ret_avg + ret_std == 0: raise ValueError("No valid metrices selected!") if isinstance(mask, np.ndarray) and len(mask.shape) == 2: # We have a single image image = [image] mask = [mask] ret_list = False else: ret_list = True length = min(len(mask), len(image)) # Results are stored in a separate array initialized with nans if ret_avg: avg = np.zeros(length, dtype=float) * np.nan if ret_std: std = np.zeros(length, dtype=float) * np.nan for ii in range(length): imgi = image[ii] mski = mask[ii] # Assign results if ret_avg: avg[ii] = np.mean(imgi[mski]) if ret_std: std[ii] = np.std(imgi[mski]) results = [] # Keep alphabetical order if ret_avg: results.append(avg) if ret_std: results.append(std) if not ret_list: # Only return scalars results = [r[0] for r in results] if ret_avg+ret_std == 1: # Only return one column return results[0] return results