Accessing Image Data

Accessing Image Data

Accessing Image Data

Canvas X Draw contains important features that allow you to analyze an image’s pixel values and measure various image properties: Image Data Viewer tool, View Data command, and Image Measurement command.

Image Data Viewer Tool

You can quickly view raw data within an image object using either the Image Data Viewer tool or View Data command. These tools are designed so you can quickly view image data “on the fly”. In addition, you can copy this data to a .txt file or spreadsheet application for further analysis.

To Use the Image Data Viewer Tool:

  1. Select the Image Data Viewer tool from the Marquee tools in the Toolbox. 
  2. Drag it across the image. The Image Data Viewer dialog box opens showing the individual pixel values for the selected area.

To Use the View Data Command:

  1. Make a selection using the Marquee tools.
  2. Click the View Data button in the Properties bar to open the Image Data Viewer dialog box.

Image Data Viewer Dialog Box

Display

Hexidecimal: Refers to the base-16 number system, which consists of 16 unique symbols: the numbers 0 to 9 and the letters A to F.

Signed decimal: Integer value which can have both positive and negative values.

Unsigned decimal: Integer value with value of zero or greater (no negative numbers).

FP 2-Decimal: Refers to a floating point value with 2 digits following the decimal.

FP 4-Decimals:Refers to a floating point value with 4 digits following the decimal.

FP 8-Decimals: Refers to a floating point value with 8 digits following the decimal.

Channel

Select a color channel from the menu. The available channels depend on the image mode; i.e., RGB, grayscale, CMYK, etc.

Copy Data To Clipboard

Click this icon to export the data to a spreadsheet or other file for analysis.

Refresh Data

Click this icon to update the data.

Lock

Click this icon to lock the dialog box and save the data view. Once locked, you can take the Image Data Viewer tool and select another data sample. Another dialog box will open so you can compare data.

Left

Indicates the position of the first pixel in relation to the left side; i.e., 43 would be the 43rd pixel from the left.

Top

Indicates the position of the first pixel in relation to the top; i.e., 29 would be the 29th pixel from the top.

Width

Indicates the width of the selected area in pixels.

Height

Indicates the height of the selected area in pixels.

An alternative method to using the Image Data Viewer tool is to export the image as a .txt file using the RAW file export filter. (See Exporting RAW Files.) However, although effective, the RAW export method may be time-consuming if analyzing several images and data is required immediately.

Image Measurement

The Image Measurement dialog box contains information about the selected image or selected regions within an image.

To View an Image’s Image Measurement at Any Time:

Choose Image | Image Measurement.

Image Measurement Dialog Box

List

This list contains the various image properties that are being measured. You can customize the data by clicking the Configure button and selecting the properties to be measured.

Each selected region within an image has its own column of data.

If you want to label the image or selected regions, select the Label Objects checkbox. The label corresponds to the column number.

Configure

Click this button to open the Image Measurement Properties dialog box. Select the properties that you want to appear in the list.

Copy

Select an column of data and click this button to copy the image measurements so you can paste them in a spreadsheet or text editing application.

Copy All

Click this button to copy all columns of data for multiple selections. You can paste them in a spreadsheet or text editing application.

Histogram

Click this button to launch the Histogram dialog box for a single column of data.

Histogram All

Click this button to launch the Histogram dialog box for multiple selections.

Image Measurement Properties

Select Properties To Measure

Select or deselect properties to customize your list of image properties to be measured.

  • Area: Total number of pixels in image.
  • Calibrated area: The area of an image measured in current Canvas X Draw units.
  • Mean: Measures the average pixel intensity.
  • Standard deviation: A numeric value that describes how widely intensity values vary.
  • Median: Middle value in the range of values; i.e.; number of pixels with intensity below the median is equal to the number of pixels with intensity that is above the median.
  • Center of mass: The x/y coordinates of the image’s center.
  • Perimeter: Measures the perimeter of the image in pixels.
  • Calibrated perimeter: The perimeter of an image measured in current Canvas X Draw units.
  • Compactness: A numeric measurement of an object’s shape. It is defined with the following equation:
  • Shape factor: The measurement of an object’s circularity. It is defined with the following equation:
  • Feret diameter: Indicates an object’s theoretical diameter if it had a circular shape.
  • Calibrated feret diameter: Measured in the current Canvas X Draw units, this indicates an object’s theoretical diameter if it had a circular shape.

Labels

  • Placement: Determine label placement. The default placement is the center of the image or selection.
  • Font:Customize the appearance of the labels. You can change font, size, and color.

See also:

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