Object recognition is a subfield of Computer Vision which consists of methods/algorithms aimed at determining whether a given object is present on a 2D image. Many object recognition systems just return a 'yes/no' answer, but there are also many methods that return the location of the object on the image by means of a bounding box.
This subfield comprises a vast range of methods, from low-complexity ones (like methods based solely on applying simple filters on the image, like colour/edges/etc.) to more complex ones in which machine learning methods (like deep learning) play a very important role.
Depending on the complexity of the objects you are planning to detect, and on the overall complexity of the images, machine learning may be completely unnecessary.
This Wikipedia page summarises many of these methods. You can start exploring from there, or you can start by using any introductory computer vision text.