<p>The study is aimed at enabling the measurement of submerged items precisely for archaeological research in the search for extinct towns like Poompuhar and Dwarka. The main purpose of the proposed work on digital reconstruction is to identify the current cultural practices, traditions, technologies and more. One of the efficient techniques is 3D photogrammetry, which can be used to measure any object while keeping a reference object nearby. The algorithm used to create a 3D model of the target item using a dataset is called modified structure from motion. Since each picture dataset’s features change depending on the physical characteristics of ocean water, underwater imaging and processing are difficult undertakings. A variety of undersea real-time data sets were used to evaluate the improved method, and it was successful in producing the desired outcome. The underwater vehicle (ROV) developed in our research lab, rotates the target item 360 degrees and takes a number of optical images of it. The 3D model of the target object is created resulting picture preprocessing and dataset improvement. With the neighbouring reference object, it is simple to measure the length, breadth and volume of the target item. The proposed initiative assists archaeologists in their investigation of conventional, vanished ancient towns.</p>