The following figure illustrates both types of image value display. The digital value display is on the left; the pixel value display is on the right.
Set Digital Value or Pixel Value and X-Y Plot. Dragging the mouse on the image will define a subsample of the image and open a window displaying an X-Y plot of the defined subsample.
Moving the X-Y plot window away from the image window allows you to watch a shifting plot while dragging the mouse across the image.
The following figure illustrates an X-Y plot.
A histogram is a distribution plot of image values for a selected image area. To display a histogram, first set either Digital Value or Pixel Value then set Histogram. Dragging the mouse on the image will define a subsample of the image and open a window displaying histogram, or distribution plot, of the defined subsample.
Moving the histogram window away from the image window allows you to watch a shifting histogram while dragging the mouse across the image.
The following figure displays a histogram.
Convert Data, on the image window Data menu, allows the user to convert image data into another data set by the general power function Y = a + b * X^c, where X is the current data point and a, b, and c are user-defined values. The conversion function is applied to every point of the image data and the data type is preserved.
Note that a backward conversion may not restore the original data. For instance, an integer data point whose value is 14 will become 1 if it is converted by the function Y = 0.1*X. The backward conversion, which is X = 10*Y, yields 10, not the orignal value. Use Undo, on the Edit menu, to restore the original data.