Replacing image pixel values

To replace the pixel values in an image, you must be very familiar with your images and understand the consequences of making such changes. That is, when you replace the pixel values in an image, you are affecting the image directly, not just the values in memory. However, you may find this feature useful in some situations. For example, if you are creating a mosaic with images containing different background values, you can replace the background values of each image so that they are all the same. After doing so, you can then create the mosaic without difficulty.

To replace image pixel values

In the OrthoEngine window, on the Tools menu, click Replace Image Values.
The Replace Image Value window appears.
In the Image file box, type the path and file name of the image you want or, to select a file, click Browse.
Beside Channel, do one of the following:
- To replace the pixels in a specific channel, in the Channel box, type or select the channel you want.
- To replace the pixels in all channels, click All channels.
Beside Replace option, do one of the following according to the value you will enter in the Value to replace box (in the next step):
- To replace all values less than the value you will enter, click <.
- To replace all values less than or equal to the value, click <=.
- To replace all values equal to the value, click =.
- To replace all values greater than or equal to the value, click >=.
- To replace all values greater than the value, click >.
In the Value to replace box, type the value to change.
In the Skip value box, type the number in the selected range that you do not want to replace, if applicable.
In the New value box, type the number that you want to use as a replacement.
In the Action list, do one of the following:
- To replace all the image pixel values equal to the value to replace by the new value, click Replace.
- To add the new value to all the image pixel values equal to the value to replace, click Add.
- To subtract the new value from all the image pixel values selected by using the value to replace, click Subtract.
- To multiply by the new value all the image pixel values selected by using the value to replace, click Multiply.
- To divide by the new value all the image pixel values selected by using the value to replace, click Divide.
Click Replace.
The image pixel values you specified are replaced.