I have preliminary results in object segmentation. what is the best way to publish them in a journal? what are the advantages and disadvantages of uploading the document to arXiv?
You could present your preliminary findings in an International Conference as a research proposal. It could be published in the proceedings of the conference ( book) without any additional payment.
Alternatively , you could write a research proposal ( in the form of an article ) and send it to an International Journal with a high impact factor - to be previewed. Just make sure it is an open access journal if they ask for a publication fee.
biorxiv.org is meant for biology. As Aditya is from physical science stream, I hope arxiv.org would be better for him. .
Another opportunity is to present your preliminary findings in Conferences. Certain journals accept preliminary findings in note, short communication, or in letter format.