For the most part one could simply use commonsense.
You mentioned a computer in your OP....that's pretty obvious it was designed. Or one can look at Mt. Rushmore and understand wind, sand and time didn't create the depictions that are seen in the side of the mountain. Common sense...right?
But at times it could be a bit more complicated than common sense....depends upon the angle from which it is viewed. For example I was once hiking and saw a large stand of pine trees....all which appeared to have been growing where nature dropped the pinecone. As I continued to walk I saw the trees from a different view and noticed they were all in rows....obviously planted. The forest was intelligently planted.
Was there a way to measure the intelligence in the creation of the pine forest? Well, you could count the rows, the spacing of the trees, the order and using common sense determine the forest wasn't natural.
But, humans were mentioned....once gain it depends on the angle....or in this case the magnification. When you peer deep into a human cell the intelligent design pops to life and processes emerge that the evos can only scratch their heads about. Assembly lines of organelle emerge which like the pine trees when viewed from the correct angel clearly show intelligent design. Now, can I measure it? I don't know. Perhaps I could count the steps required for the organelle to accomplish to create a finished item and assign a value to it. Is that what you are looking for Pixie?
The following is a video which depicts one of the activities that occurs in a cell. Pixie, how would evolutionism using random chance and some unidentified form of natural selection produce such sophistication and complexity?