VIOLATIONS of human rights get the most attention when they occur in the glare of major news - China's crackdown on students protesting for democracy, for example, or the past year's drama in the Gulf, when the whole world became aware of Iraq's pillaging of Kuwait.But the imprisonment, torture, and killing of individuals for exercising rights of conscience and expression go on continuously, typically out of the view of cameras or reporters. This year, as each year, Amnesty International has moved those ongoing human-rights abuses out of the shadows. Its 1991 report, detailing the world's assault on basic rights during 1990, is typically comprehensive. The United States is scrutinized for its application of the death penalty; Norway and Switzerland draw criticism for imprisoning conscientious objectors. Truly horrific events are chronicled in such out-of-the-way venues as Mauritania, where blacks living in the south of the country were arrested by the thousands and randomly killed by government troops. In Chad, 300 political prisoners were summarily executed just before President Hissein Habre was ousted last November. Sri Lanka's violence claimed thousands who were executed without judicial process or who simply "disappeared." The long-running rights stories are here too: death squads in El Salvador and Guatemala, continued imprisonment of dissidents in China, detention without trial of Palestinians by Israel. Matters of definition may arise. Capital punishment and incarceration of those who refuse military service may not strike some as abuses of rights. But there's no question that the overall picture pieced together by Amnesty is convincing. It can't be ignored.