White Balance¶
Corrects the exposure of an image. A color standard can be specified.
white_balance(device, img, mode='hist, debug=None,roi=None,)
returns device, img
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Parameters:
- device - device number. Used to count steps in the pipeline
- img - A gray scale image on which to perform the correction
- mode - either 'hist' or 'max', if 'hist' method is used a histogram for the whole image or the specified ROI is calculated, and the bin with the most pixels is used as a reference point to shift image values. If 'max' is used as a method, then the pixel with the maximum value in the whole image or the specified ROI is used as a reference point to shift image values.
- debug - None, "print", or "plot". Print = save to file, Plot = print to screen. Default = None
- roi - A list of 4 points (x, y, width, height) that form the rectangular ROI of the white color standard. If a list of 4 points is not given, the whole image is used.
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Context:
- Used to standardize exposure of images before thresholding
Original image
import plantcv as pcv
# Corrects image based on color standard and stores output as corrected_img
device, corrected_img = pcv.white_balance(device,img,'hist', debug="print",(5, 5, 80, 80))
Corrected image