RenderedImage
. A "bin" is a container, where each element stores the total number of pixel samples of an image whose values lie within a given range. A histogram of an image consists of a list of such bins whose range does not overlap with each other (mutually exclusive). For an image that has multiple samples per pixel (multi-banded images), a separate list of bins represents each individual band.
A "low-value" specifies the lowest inclusive pixel value to be checked, and a "high-value" specifies the highest exclusive pixel value to be checked. Therefore, the width of a bin (binWidth
) is determined by (highValue - lowValue) / numberOfBins
. The range of bin i
is defined as from lowValue + i * binWidth
inclusive to lowValue + (i + 1) * binWidth
exclusive.
The image may have any data type. Its histogram may be accumulated over the entire image, or over a specific region-of-interest (ROI) within the image's bounds. Furthermore, the horizontal and vertical subsampling factors specify the rate of sampling in the two directions, so that only every nth pixel will be counted. This allows the accuracy of the histogram to be traded for the speed of the computation. Of course a subsampling rate of 1 means every pixel will be counted.
The "Histogram" operator generates the histogram data of an image and uses this object to store the final pixel counts. The operator returns an instance of this class when a request is made via the getProperty
method for the "histogram" property. The actual bins may be obtained by calling the getBins
method.
@see ROI
@see com.lightcrafts.mediax.jai.operator.HistogramDescriptor
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