Digital Image Processing Tutorial-Mosaic Process

In this article further important processes will be explained. After acquiring satellite images based on study area one may need more than one satellite image to cover study area for analysis. In this case similarity and uniformity for all satellite images become essential to achieve qualitative and quantitative accuracy in analysis. It is also to keep uniform contrast, brightness and enhancement level for satellite images for better interpretation and analysis.

Advantages of Mosaic Tool

If any user have more than one satellite image for his study area than make a single image from all satellite image is necessary process for similar outcome. Mosaic all satellite image of study area to make a single satellite image through mosaic tool available in image processing software. Using this mosaic tool all satellite images which are in separate file can be combined in single file for further analysis. Advantage of this process, that all images can be kept in similar brightness and contrast level as well as balanced enhancement for all satellite images.

Mosaic Tool

By using tools ‘n’ number of images can be combined together and can prepare a mosaic image of study area. To use this tool in Erdas Imagine below steps need to follow-

• Select DataPrep from main tools window of Erdas imagine then a data preparation tool window will open in that go to Mosaic Images and click on it.
• A Mosaic images tool will open, in that select and click on Mosaic tool for further process of Mosaic images.
• A mosaic tool window will open in that tool many options were there in the top such as File, Edit, Process and Help. In the beginning Edit tool will use to add all images which need to mosaic in single file.
• Go to Edit tool and click on Add Images option then file browser will open, with that select all images for mosaicing process.
• After adding all images for mosaic process, these images can be arrange in sequence, such as image which you need to keep up than move it forward or can be send back using icons highlighted in the red box as shown in the below figure after adding image process.

Figure- Mosaic Tool and Mosaic Process Steps

• Then go to Edit tool and select color corrections option through which brightness and contrast can be corrected as well enhancement similarity can be created using this tool.
• To create mosaic, go to Process and click Run Mosaic. The shortcut icon for Run mosaic is also there highlighted in red color box in the last of the process in above image.
• When click on Run mosaic, a browser window will open in that need to define output image, its mean the file which will be created using this mosaic process.

Use of Mosaic tool

In this mosaic process one can also define pixel size i.e. spatial resolution. Sometime file size become very big and one may need mosaic only for display purpose then spatial resolution can be reduced to medium or low to save space and for faster process. Mosaic and subset are very common process, which are very frequently used together in image pre-processing. As it facilitate and speed up the image processing and save precious time of user.