HIST_STATS Function (PV-WAVE Extreme Advantage)

Computes six different statistical operations on image histograms.

Usage

result = HIST_STATS(hist_data) 

Input Parameters

hist_data—A 1D or 2D long array containing one or more histograms.

Returned Value

result—A double array with six statistical results (mean, variance, skewness, kurtosis, energy, and entropy, respectively) for each histogram in the hist_data array.

Keywords

Binsize—The bin size used to compute the histogram. (Default: 1.0)

Maxgray—Specifies the maximum graylevel that was considered in computing the histogram values (hist_data). (Default: N_ELEMENTS(hist_data))

Mingray—Specifies the minimum graylevel that was considered in computing the histogram values (hist_data). (Default: 0)

Discussion

Histogram statistics are useful for quantitative image feature descriptions. The statistics returned by HIST_STATS are computed for the normalized image histogram, P, where P is the histogram divided by its total. The statistics returned by HIST_STATS are defined as follows:

Mean:

 

Standard Deviation:

 

Skewness:

 

Kurtosis:

 

Energy:

 

Entropy:

 

Example

; Read an image.

image = IMAGE_READ(!IP_Data + 'airplane.tif')

image_hist = IPHISTOGRAM(image('pixels')

stats = HIST_STATS(image_hist)

; Compute the histogram statistics and print them to the screen.

PRINT, stats

See Also

IPHISTOGRAM