Converting Image Data
If required, you can restructure image data for different analysis needs. For example, you may have to convert datasets to 32-bit integers if you plan to perform certain arithmetic operations or Laplacian filtering. You should note that transformations do not change the dimensions or coordinates of input images. However, data values may be shifted, scaled, or cast to a new primitive data type. In the Convert Dataset panel, shown below, you can also threshold the input values and select an output range.
Image Converter panel
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Description |
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Input ranges |
Displays the range of the data that will be converted. Input data can be represented either as byte, unsigned short, unsigned integer, or float, within their respective ranges. If no filtering is requested, the input range covers all values between the minimum and maximum data values of the input image. |
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Filter values |
Specifies the data range that will be converted. If filtering is selected, values from either side of the data spectrum will be excluded from the output. Filter min… Specifies the lower threshold value. Filter max… Specifies the upper threshold value. Replacement value… You can specify the value that will represent all the data below the Filter min and above the Filter max values. |
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Data type |
Lets you select a primitive data type for the output dataset — either byte (8 bits), unsigned short (16 bits), unsigned integer (32 bits), or float (32 bits). Byte (8 bits)… 8 bit code one gray value, each bit has either value 0 or value 1. Consequently, 28 = 256 different gray values are possible, with gray values from 0 to 255 (unsigned). Unsigned short (16 bits)… 216 = 65,536 different gray values are possible, with gray values from 0 to 65,536. Unsigned integer (32 bits)… More than one million different gray values. Gray values from 0 to 1,048,575. Float (32 bits)… Effective gray values dynamics 32 bit float. |
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Normalize |
If selected, the data spread will be normalized within the selected Minimum and Maximum range values. |
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Range values |
After selecting an output primitive data type, the Min and Max range fields will display the conversion values. If Normalize is selected, these fields can be edited to delimit the range values within which the data will be spread. If clipping occurs, the minimum or maximum value of the output range or both will be equal respective to the smallest or largest value that can be represented by the selected output data type. Data values below the lower limit or above the upper limit will be clamped. |
How to Convert Image Data
- Right-click the required dataset in the top section of the Data Properties and Settings panel and then choose Convert Dataset in the pop-up menu.
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The Image Converter panel appears on the Dataset Tools tab.
- Do the following if you need to specify the range of data that will be converted:
- Check the Filter values option in the Input dataset box.
- Enter the required minimum and maximum threshold values in the Filter min and Filter max edit boxes.
- Enter a replacement value for all values that will be excluded from the output dataset in the Replacement value edit box, optional.
- Choose an output data type — Byte (8 bits), Unsigned short (16 bits), Unsigned int (32 bits), or Float (32 bits) — in the Output dataset box.
- Do the following if you need to normalize the output dataset values within a selected range:
- Check the Normalize option in the Output dataset box.
- Enter the minimum and maximum data values that will define the normalized range in the Min range and Max range edit boxes.
- Check the Create new dataset option, if required. If checked, a new dataset will be created with the selected changes.
- Click the Apply button.
