Image Stretching

Feature Description

During the acquisition of remote sensing imagery, factors such as sensor characteristics and atmospheric conditions often lead to an unsatisfactory dynamic range distribution of brightness in the source data, resulting in insufficient contrast and difficulty in discerning details during direct display. Image stretching, through standardized mathematical transformations of pixel values, primarily aims to achieve the following two core objectives:

Optimize Visual Effect: By adjusting the distribution and contrast of pixel values, it enhances the visual distinction of spectral or texture differences among different ground objects.
Achieve Bit Depth Conversion: For example, converting high-bit-depth data (e.g., 16-bit) to lower-bit-depth formats (e.g., 8-bit) more suitable for storage, transmission, or display. In this process, stretching methods are used to preserve key information and reduce pixel loss.

SuperMap iDesktopX Available starting from Update 1 of the 2025 version.

Parameter Description

Parameter Name	Parameter Interpretation	Parameter Type
Image File List	Manages the image files to be stretched. Add Image: Sets the images to be stretched, supporting formats: .tiff, .tif, .img, .pix. Add File: Select one or more image files from the local directory. Add Folder: Select a folder from the local directory; all images within that folder and its subfolders will be automatically retrieved. Add List: Select a manifest file (.csv) from the local directory; images will be retrieved based on the image names and path information in the manifest file. Add Mosaic Data: Select a mosaic dataset from the current workspace. Select All: Selects all files in the list. Select Reverse: Inverts the selection state of all files in the list. Delete*: Removes the selected records from the list.	DatasetImage
Output Directory	Sets the storage path for the result images.	String
File Type	Sets the storage type for the result images. Four options are provided: Unset, Tiff/GeoTIFF, Erdas Image, and PCIDSK. The default is Tiff/GeoTIFF. When Unset is selected, the output will use the original storage type of the image.	FileType
Compression Method	Sets the compression method for the output image. Available only when the output format is Tiff/GeoTIFF. Default is NONE.	CompressMethod
Pixel Format	Sets the pixel bit depth for the processed output channels. Available options include: 8-bit Unsigned (default): Unsigned 8-bit integer. 16-bit Unsigned: Unsigned 16-bit integer. 16-bit: Signed 16-bit integer. 32-bit: Signed 32-bit integer. This option is not available when file type is PCIDSK.	PixelFormat
Stretch Method	Sets the method for image stretching. Default is Percent Clip. Other methods include Gaussian, Gamalashin, Histogram Equalization, and Logarithmic Stretch. For more method introductions, please refer to Image Stretching Methods.	ImageStretchingType
Minimum	Available when Stretch Method is Percent Clip. Default value is 1.	Double
Maximum	Available when Stretch Method is Percent Clip. Default value is 99.	Double
Gaussian Standard Deviation Coefficient	Available when Stretch Method is Gaussian. Default value is 3.	Integer
Gamalashin Coefficient	Available when Stretch Method is Gamalashin. Default value is 0.5.	Double
NoData	Sets the value for the NoData area of the image. Default is 0.	Double
Index	Sets the indices to be exported, corresponding to the sequence and band values.	Boolean

Output Result

Outputs the result image data to the local folder.