Computer graphics systems are typically used to examine and perform operations on large, detailed, digital images. Examples of such tasks include an artist editing a high resolution image for print publication, an image analyst examining an aerial photograph, and a silicon chip designer examining chip layouts. Often, users of such graphics systems need to zoom-in to specific regions of a particular image in order to recognize detail. When zoomed-in to a specific region of interest, often the entire image will not fit on the display screen of the system and hence a large portion of the image may no longer be visible to the user. If the user, still zoomed-in, wants to navigate to a different region of the image, it will be necessary to either first zoom-out, then zoom back in, or to pan repeatedly until the new region of interest is located. Both of these operations are slow and time consuming. Thus, traditional methods of navigating large images such as panning and zooming are inefficient. This is an example of what has been referred to as the “screen real estate problem”.
U.S. Pat. No. 6,271,854 to Light discloses a method for navigating in three-dimensional graphic scenes. In Light, a user may zoom-in to an object in a scene by clicking on the object. To zoom-out to the original scene, an “opportunistic” control icon is provided. By clicking on this control, the original scene is redisplayed. The user may then select another object in the original scene to zoom-in on. However, the screen real estate problem remains evident in Light. When viewing an object which has been zoomed-in, the relationship between that object and other objects in the original scene may be lost to the user.
A need therefore exists for an improved method and system for navigating digital images. Consequently, it is an object of the present invention to obviate or mitigate at least some of the above mentioned disadvantages.