text:  The Dvorak technique ( developed between 1969 and 1984 by Vernon Dvorak ) is a widely used system to estimate tropical cyclone intensity ( which includes tropical depression , tropical storm , and hurricane / typhoon / intense tropical cyclone <unk> ) based solely on visible and infrared satellite images . Within the Dvorak satellite strength estimate for tropical cyclones , there are several visual patterns that a cyclone may take on which define the upper and lower bounds on its intensity . The primary patterns used are curved band pattern ( <unk> @-@ <unk> ) , shear pattern ( <unk> @-@ <unk> ) , central dense <unk> ( <unk> ) pattern ( <unk> @-@ <unk> ) , central cold cover ( <unk> ) pattern , banding eye pattern ( <unk> @-@ <unk> ) , and eye pattern ( <unk> - <unk> ) . 
  