Overview
This is supported at ArcGIS 10.1 and later.
This topic discusses the histogram object as returned by the REST API.
A histogram consists of a dictionary of name-value pairs.
JSON syntax
        {
  "size" : <size>, //int, number of bins
  "min" : <min>, //number, minimum value
  "max" : <max>, //number, maximum value
  "counts" : [<count1>,<count2>,<count3>] //integer(64bit), counts of pixels in each bin. The width of each bin is (max-min)/size.
}
JSON example
        {
      "size" : 256, 
      "min" : -0.5, 
      "max" : 255.5, 
      "counts" : [
        42915, 
        23218, 
        24832, 
        25925 
        36054, 
        57097, 
        61278, 
        65211
        ...
        ]
}