Image Fusion

Feature Description

Image fusion is a technology that uses various methods to composite and transform multiple images from different times, different sensor systems, different resolutions, and different spectral bands to generate new images. For example, after fusing a panchromatic orthoimage with a multispectral orthoimage, a high-quality image with both high spatial resolution and high spectral resolution can be obtained. This technology effectively combines the advantages of various images, providing richer information support for subsequent analysis and applications.

Figure: Multispectral before fusion Figure: Panchromatic before fusion Figure: Multispectral after fusion

Parameter Description

Parameter Name Parameter Interpretation Parameter Type
Data Type

This parameter is available only when the function is launched from the Satellite image processing tab -> DOM Data Production group -> Image Fusion.

Select the source of input image data, providing two options: Image Files and Mosaic Dataset. The default is Image Files. You can manage image files using the Add, Select All, Select Reverse, Delete, and Settings functions in the Image file list.

  • Add: Provides four ways to input image files: Add File, Add Folder, Add List, and Add Mosaic Data. When selecting Add Folder, all image files in that folder (including subfolders) will be automatically fetched.
  • Select All: Select all records in the list.
  • Select Reverse: Inverse selection of all records in the list.
  • Delete: Delete the selected records from the list.
  • Settings: When the input panchromatic and multispectral images are not fully paired, you can manage pairing rules through the Settings button to complete pairing of all images.

 
Panchromatic Data Source

This parameter is available only when the function is launched from the Satellite image processing tab -> DOM Data Production group -> Image Fusion.

Specify the data source where the panchromatic image data is located after selecting Mosaic Dataset in Data Type.

DataSource
Panchromatic Data Specify the mosaic dataset where the panchromatic image data is located after selecting Mosaic Dataset in Data Type. If it is a production workflow, it is display-only and not editable. DatasetMosaic
Multispectral Data Source

This parameter is available only when the function is launched from the Satellite image processing tab -> DOM Data Production group -> Image Fusion.

Specify the data source where the multispectral image data is located after selecting Mosaic Dataset in Data Type.

DataSource
Multispectral Data Specify the mosaic dataset where the multispectral image data is located after selecting Mosaic Dataset in Data Type. If it is a production workflow, it is display-only and not editable. DatasetMosaic
Fusion Method

Specify the image fusion method. The default method is Gram-Schmidt.

  • PanSharp: An image fusion method based on the least squares grayscale relationship. It adjusts the grayscale values of each band of the multispectral image through a linear regression model between the multispectral and panchromatic images, matching their radiation characteristics and reducing color deviation after fusion. Suitable for remote sensing applications requiring high spectral accuracy, such as agricultural monitoring and environmental assessment.
  • Gram-Schmidt: An improved method based on the Gram-Schmidt orthogonal transformation. It adaptively adjusts the linear relationship between each band of the multispectral image and the panchromatic image to generate a brightness component that better meets actual needs. This method features high spectral fidelity and good spatial detail preservation.
  • CNBROVEY: Color Normalized Brovey is an improved Brovey transform image fusion method. By introducing a color normalization strategy, it optimizes the fusion process between multispectral and panchromatic images. It enhances spatial details while preserving original spectral characteristics as much as possible, suitable for scenes balancing spectrum and details.
  • HSV: Hue Saturation Value is an image fusion method based on color space. It converts the multispectral image from RGB color space to HSV space, replaces or enhances the brightness component using the high spatial resolution of the panchromatic image, thus improving image details while preserving hue and saturation. Suitable for RGB band fusion, less effective for non-visible bands (e.g., near-infrared). Supports only 8-bit image data.
  • PCA: Principal Component Analysis is an image fusion method based on statistical feature extraction. It converts the multispectral image to principal component space and replaces the first principal component (PC1) with the panchromatic image, achieving effective fusion of spatial details and spectral information. This method improves spatial details of the multispectral image while retaining most spectral information, suitable for remote sensing applications with high spatial resolution requirements. However, there may be a risk of spectral distortion, and spectral fidelity is average.
  • NND: Non-Negative Decomposition is an image fusion method based on non-negative matrix factorization (NMF). It jointly decomposes multi-source images (e.g., multispectral, panchromatic, infrared) to extract shared features (e.g., spatial structure) and independent features (e.g., spectrum, thermal radiation), and performs fusion based on that. Suitable for fusion between multimodal data, but the computation time is relatively longer.
FusionMethod
Predefined Fusion Weights Check this checkbox to use predefined weights for fusion. This is only effective for PanSharp and Gram-Schmidt methods. If unchecked, adaptive weights will be used for fusion. Boolean
Sharpening Factor Used to adjust the sharpness of the fused image. The default is 1. Double
Resampling Method Set the resampling method after image fusion. Provides three options: Nearest, Bilinear, and Cubic. The default is Bilinear. For more method descriptions, please refer to Resampling Method. ResampleMethod
Export Directory

Set the storage path for the result image.

If executing a production workflow, use the Processing parameter in Set Image Path or Add Orthophoto, and this field is not editable.

File
Output Format

Set the storage type of the result image. Provides four options: Not Set, Tiff/GeoTIFF, Erdas Image, and PCIDSK. The default is Tiff/GeoTIFF. Selecting Not Set means using the original storage type of the image for output.

If executing a production workflow, use the Output Format parameter in Set Image Path or Add Orthophoto, and this field is not editable.

FileType
Compression Method

Set the compression method for the output image. Only available when the output format is Tiff/GeoTIFF. The default is NONE.

If executing a production workflow, use the Compression Method parameter in Set Image Path or Add Orthophoto, and this field is not editable.

CompressMethod
Add Results to Map Window

This parameter is available only when the function is launched from the Satellite image processing tab -> DOM Data Production group -> Image Fusion.

Checked by default, meaning that after the function executes successfully, the result data will be added to the map window for display.

Boolean
Create Image Pyramid

Checked by default, it can build pyramids for the image data according to the specified resampling method, thus improving the zoom display rendering and performance of the image.

If executing a production workflow, use the Create Image Pyramid parameter in Set Image Path or Add Orthophoto, and this parameter is not displayed.

Boolean
Resampling Method

Available when Create Image Pyramid is checked. The default is Average. For more method descriptions, please refer to Resampling Method.

If executing a production workflow, use the Resampling Method parameter in Set Image Path or Add Orthophoto, and this parameter is not displayed.

PyramidResampleType
Asynchronously Create Statistics

When browsing an image, the layer will be stretched based on statistical information. If the image has no statistical information, it will be displayed according to the default stretch method, and 8-bit data will not be stretch-displayed. Checked by default, meaning that statistics will be created for the image in the background without affecting workflow execution. If unchecked, statistics will be created simultaneously when executing this tool, which may consume time.

If executing a production workflow, use the Asynchronously Create Statistics parameter in Set Image Path or Add Orthophoto, and this parameter is not displayed.

Boolean

Output Result

  • Output image data that combines features of both panchromatic and multispectral images to a local folder.
  • Automatically create an image fusion mosaic dataset in the OrthoData datasource based on the output image data.

Related Topics

Generate Orthophotos

Multispectral and Panchromatic Registration

True Color Output

Image Color Balancing

Image Mosaic