If you have C++ background i suggest you to use OpenCV library ( http://opencv.org/ ) where you can find function that, for example, looks for blobs in your image and computes area and stuff like that. There are several example so you can learn to use that library quickly. 

ImageJ is free, has a good feature set, lots of additional modules (plugins) and a very helpful user community. Its particle analysis measures all the things you mentioned. For life sciences there is Fiji, basically ImageJ with a whole raft of plugins bundled. Many of these are helpful for analysis of microscopy images. Of course I have no idea what your images look like and how difficult it is from an image analysis point of view, but for most stuff ImageJ/Fiji works well.

It also has a macro language (and recorder) for simple automation of repetitive tasks. Additional modules are fairly easy to develop if you can program in Java. I quite often use it as a image analysis library when programming stand alone programs for very specific types analysis that we do a lot (in my case bone histomorphometry) . Programming skills are not necessary to use the program though.

Thank you for the quick answers, I appreciate it.

Dear Mertol, could you upload one example image. It will be much easier to discuss the right program with one image in mind. We developed some IA algorithms. You might want to look on the publication as well

http://www.sciencedirect.com/science/article/pii/S0098135412001603

ImageJ Free software allows you to count particles, or object from different size (which parameter you can cotrol) and to measure different statistics values. It is very useful for that.

ImageJ is a good suggestion. However if you have a lot of images to analyze you might want to look into CellProfiler [http://www.cellprofiler.org/] This is a free software developed for biologists without a background in image analysis. It is designed for high throughput where you put together a pipeline with different image analysis steps and your measurements are easily exported to spreadsheets or databases. If you need help getting started let me know.

I tried all suggestions, ImageJ is very useful and free.

Thank you for your time

I would defintely recommend you visit www.MIPAR.us.

It is very powerful and intuitive 2D/3D image analysis software written by scientists/end-users and is about to be released as a free trial on December 14th. You can sign up on the site as well as submit images/datasets to test.

There are many image analysis options available, but I think you may just find MIPAR to be something special if you give it a try!