Adobe Photoshop CS4 - Manual (Page 618)

611 USING PHOTOSHOP CS4
3D and technical imaging
Last updated 1/10/2010
Gray Value This is a measurement of brightness, either from 0 to 255 (for 8-bit images), 0 to 32,768 (for 16-bit images),
or 0.0 to 10 (for 32-bit images). For all gray value-related measurements, the image is internally converted to grayscale
(equivalent to choosing Image > Mode
> Grayscale) using the default grayscale profile. Then the requested
calculations (mean, median, minimum, maximum) are calculated for each feature and for the summary.
Height Height of the selection (max y - min y), in units according to the current measurement scale.
Histogram Generates histogram data for each channel in the image (three for RGB images, four for CMYK, and so
on), recording the number of pixels at each value from 0 to 255 (16-bit or 32-bit values are converted to 8-bit). When
you export data from the Measurement Log, the numeric histogram data is exported to a CSV (comma-separated
value) file. The file is placed in its own folder at the same location where the measurement log tab-delimited text file is
exported. Histogram files are assigned a unique number, starting at 0, and progressing by 1. For multiple selections
measured at once, one histogram file is generated for the total selected area, plus additional histogram files for each
selection.
Integrated Density The sum of the values of the pixels in the selection. This is equivalent to the product of Area (in
pixels) and Mean Gray Value.
Label Identifies and automatically numbers each measurement as Measurement 1, Measurement 2, and so on. For
multiple selections measured simultaneously, each selection is assigned an additional Feature label and number.
Length Linear distance defined by the Ruler tool on the image, in units according to the current measurement scale.
Perimeter The perimeter of the selection. For multiple selections measured at once, one measurement is generated for
the total perimeter of all selections, plus additional measurements for each selection.
Scale The measurement scale of the source document (for example, 100 px = 3 miles).
Scale Units Logical units of the measurement scale.
Scale Factor The number of pixels assigned to the scale unit.
Source Source of the measurement: Ruler tool, Count Tool, or Selection.
Width Width of the selection (max x - min x), in units according to the current measurement scale.
Create a data point preset
1 Choose Analysis > Select Data Points > Custom.
2 Select data points to include in the preset.
3 Click Save Preset and name the preset.
4 Click OK. The preset is saved and is now available from the Analysis > Select Data Points submenu.
Edit a data point preset
1 Choose Analysis > Select Data Points > Custom.
2 Choose the preset you want to edit from the Preset menu.
3 Select or deselect data points. The Preset name changes to Custom.
4 Click Save Preset. Enter the original preset name to replace the existing preset, or a new name to create a new preset.
Delete a data point preset
1 Choose Analysis > Select Data Points > Custom.
2 Choose the preset you want to delete from the Preset menu.
3 Click Delete Preset, then Yes to confirm the deletion.