Adobe Photoshop CS3 - Manual (Page 607)

PHOTOSHOP CS3
User Guide
600
Note: When you measure with a particular tool, only the data points associated that tool will be displayed in the log,
even if other data points are selected. For example, if you make a measurement with the Ruler tool, only the Ruler tool
data points will appear in the Measurement Log, along with any Common data points that are selected.
4 Choose an image feature and measurement tool to match the selected data points. Do one of the following:
• Create one or more selections on the image.
• Choose Analysis > Ruler Tool, or click the Ruler tool in the toolbox, then use the tool to measure the length of an
image area.
• Choose Analysis > Count Tool, or click the Count tool in the toolbox, then count items in the image.
5 Choose Window > Measurement Log to open the Measurement Log palette.
6 Choose Analysis > Record Measurements, or click Record Measurements in the Measurement Log palette.
Note: If your currently selected data points do not correspond to the your current measurement tool, you are asked to
select data points for that tool.
The Measurement log has columns for each data point you selected in the Measurement Data Points dialog box. Each
measurement you make enters a new row of data in the Measurement Log.
If you measure multiple selected areas on the image, one row of data is created in the log containing summary or
cumulative data for all selected areas, followed by a row of data for each selection area. Each selection area is listed
as a separate Feature in the Label column of the log and assigned a unique number.
You can repeat steps 2 through 6 for a variety of different selections in the same or multiple documents. The
Document column in the Measurement Log reflects the source of the measurement data.
Measurement Data Points
Angle Angle of orientation (
±
0-180) of the Ruler tool.
Area Area of selection in square pixels, or in calibrated units according to the current measurement scale (such as
square millimeters).
Circularity 4pi(area/perimeter 2 ). A value of 1.0 indicates a perfect circle. As the value approaches 0.0, it indicates an
increasingly elongated polygon. Values may not be valid for very small selections.
Count Varies according to the measuring tool used. Selection tool: the number of discontiguous selection areas on
the image. Count tool: the number of counted items on the image. Ruler tool: the number of Ruler lines visible (1 or 2).
Date and Time Applies a date/time stamp of when the measurement occurred.
Document Identifies the document (file) measured.
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