A bit more information is needed to properly answer this question. What is the background, and what are the objects you are trying to identify? Depending on the simplicity of the task, you may be able to use generic non-neural network based computer vision techniques. For instance, if the background is a solid or completely stationary you could try background subtraction and clustering. If the objects are roughly circular, you could try using a Hough transform. See openCV packages and documentation for this.
However, in general, if the specific identities of the objects are important (i.e. if they are unique) you’ll likely have to used supervised learning to train a model to recognize these objects. Again, there may be an easy cheat depending on the details of the task but it’s hard to say based on your description.