The technique of interferometric imaging has enabled remarkable
precision, resolution and sensitivity of telescopes at radio
wavelengths. Sensitivity of an Interferometric telescope scales with
the number of antennas in an antenna-array telescope. While the
resolution is proportional to the largest separation between these
antennas, the precision depends on the stability of the signal
collected over a range of time and frequency. Noise limited imaging
with such telescopes therefore critically depends on precise
calibration of the data, which in-turn requires detailed understanding
of the various electronic and atmospheric elements in the signal path.
With the wide-band receivers of modern telescopes, wide-field
wide-band imaging using calibrated data requires detailed
understanding of the optics involved in using the technique of Earth
rotation aperture synthesis. Such telescopes are fundamentally
indirect imaging devices which only partially samples the data space.
Noise-limited image reconstruction is therefore fundamentally an
iterative process. Along with large volume of data required to reach
the full potential of the telescopes, this leads to enormous
size-of-computing requirements. The need to understand telescope
hardware, instantaneous atmospheric models, telescope optics, signal
processing techniques, computational numerical techniques, computer
science techniques, scientific software development techniques and
High Performance Computing (HPC) and High Throughput Computing (HTG),
makes algorithms R&D a highly inter-disciplinary field of research.
Depending on the individual interest, this makes research in this
field exciting and intellectually challenging with opportunities
for continuous growth.

In this talk, with the goal of conveying the excitement, joys and
challenges of algorithms R&D in this area, I will give an overview of
what I think is required in terms of calibration and imaging
algorithms to enable the full potential of a modern Interferometric
radio telescope in a manner that allows users of the telescope to
largely focus on the astrophysical goals. This will include experience
of my personal journey in this field, fundamental advances in the past
few decades, the current state-of-the-art algorithms in a few areas of
interest and some results. I will also spend some time discussing
what I think are the current and future needs -- specifically to
convey the challenges and the excitement that lies ahead.