1. A display and/or operating device for controlling machines, comprising: a projection device for projecting an image onto a projection area; an acquisition device for scanning said projection area; a control computer connected to said projection device and to said acquisition device for controlling said projection device and said acquisition device; and said control computer being programmed: to carry out an analysis of said projection area with said acquisition device; and to control content of said image to be projected as a function of a result of said analysis of said projection area.