I am using Python to design a software, and the image processing is one of the steps. I am using ImageJ to realize this.
Since there is a Jython interpreter within I
Depending on the size of the image, you could use the javabridge connector developed by the Cell Profiler group. It is however notoriously slow.
If you want to design your own binding to ImageJ, you can use jepp/jpype couple, but it will be a lot of work.
The easiest way of doing it would probably be to save your image from ImageJ to an external file and write a macro that would save image, start your custom python processing script, and then re-open the processed image.