The invention belongs to the technical field of cloud measurement, and particularly relates to a cloud region identification and cloud amount calculation method and
system based on an all-
sky imager, a normalized difference
processing mode is selected to identify a cloud region, and a brightness threshold is introduced for a
sky image which is strong in sun illumination and is not completely covered by a cloud layer; selecting an initial threshold value based on a maximum between-class
variance method, and selecting a brightness threshold value for the
sky image into which the brightness threshold value is introduced by using the maximum between-class
variance method; performing cloud region preliminary identification on the whole-sky image through the initial threshold value, and adjusting the threshold value according to image features to realize cloud region identification; performing morphological
smoothing processing on the sky image after the cloud region identification; geometric correction is carried out on the image after
smoothing processing, and the
cloud cover is calculated; the method has the advantages that the sky image is processed through differentiation, the brightness threshold value is introduced into the strong light interference cloud region, the
noise influence is reduced by combining morphological
smoothing processing, the cloud region recognition precision is effectively improved, and the cloud amount
calculation error is finally reduced through geometric correction.