Hi zli034,

Using AI techniques to recognize and classify the items of your store is a bad idea. There are so many challenges to be solved in your particular application that the computational cost and the training required of your personnel will be many times higher than using an alternative as putting bar codes on the items. Just to give you an idea of the challenges, lets focus only on the shape matching part (even though, you already mentioned that you also need to match for color). Here you will have a number of challenges: your system has to be good enough to be robust against changes in orientation, occlusions, and deformations. To minimize the problem, you have at least two options:

1. train your cashiers to place the item in the same position every time, to adjust it to have a certain shape that will be easily recognized, and to avoid getting in the way of the camera. This will involved a lot of training. You could check the challenges associated with image guided surgery applications (for that, you would need to do a Google seacrh) to have an idea of all the problems of solving this type of problems in real time (you will need real time unless your customers are willing to spend a lot of time at the cashier)
2. develop a state of the art algorithm that can do the shape matching in real time (for the sake of your customers), has a 100% of accuracy (for your own sake) and is robust against occlusions, changes in light conditions, deformations, and changes in orientation. If you succeed in making such an algorithm, you better patent it because you cannot imagine how valuable it would be.

In short, you better go with the bar code solution or with any solution that involves identifying a small identifier that you put on every item.

Please, let us know if you have another question.

Cheers,