A digital microscope, whether a scanning electron microscope (SEM), transmission electron microscope (TEM), a scanning transmission electron microscope (STEM), a small dual beam microscope (SDB), focused ion beam microscope (FIB) or a light microscope (LM) produce and display a set of digital pixels. Such a digital pixel set typically contains far more data than a human viewer can perceive. The display gray scale, for example, must accommodate all digital pixel values in the image, and therefore displays regions of lower contrast in a manner that may appear to the viewer as an undistinguished field of gray, thereby preventing a human viewer from distinguishing features.
In many types of images, such as biological images, fields of low intensity (dim) pixels, corresponding to soft tissue, are interspersed with high intensity (bright) pixels, corresponding for example, to bones. The same phenomenon occurs in images of integrated circuits, gathered for example, by a focused ion beam (FIB) device, with some surfaces providing a low intensity field of pixels. As noted, the gray shade scale used must be large enough to encompass all the pixel intensities in the image. But this larger scale may show similar intensity pixels as having the same gray shade, or gray shades so similar that the variation is not apparent to a human viewer.
In addition, for assemblies in which an imaging device feeds a display screen, there are frequently instances in which the imaging device could gather more information on a region-of-interest within an area being displayed, if there was a simple way for a user to indicate a region for which more data should be gathered. For example, a scanning device, such as a scanning electron microscope (SEM) may be able to use a narrower beam and a tighter scan pattern or a decreased scan rate or increased sampling rate, to yield more pixels per unit area. For the larger region of the original image, the greater number of pixels yielded by these techniques would be more than could be practically used in the provided display space. In addition, the imaging device can tune its sampling gray-shade scale and range of focus differently, for a smaller region, within the image, thereby bringing greater detail and clarity to that region. But it appears that there is currently no easy way for a user to take advantage of these capabilities, within the context of the larger original image.
Image Diagnost International, at its website http://www.imagediagnost.de/english/, shows a mammography image display having a moveable and size adjustable spotlight that matches the gray shade scale to the gray shades in a spotlight region. In similar measure, Dexis Digital Diagnostic Imaging, having a website at http://www.dexis.com, shows a system having a spotlight that provides gray-shade enhanced imagery over a spotlight area.
U.S. Pat. No. 6,889,113, assigned to the assignee of the present application, discloses an image display assembly in which the user may control the display device or the image forming device or both, by dragging and dropping a shape, originated in a separate program, onto the image. There appears to be no disclosure, however, of spotlight image enhancement for improved viewing by a person.
A proposed method of image enhancement, to facilitate the examination of moles on a human patient's skin, was presented in “Contrast Enhancement in Dermoscopy Images by Maximizing a Histogram Bimodality Measure”, by Celebi et al., Proceedings of the IEEE International Conference on Image Processing (ICIP 2009). The method enhances the imagery by choosing an RGB to gray scale conversion weighting scheme that maximizes the bimodality of a histogram of pixel intensity for the resultant image. This increases the efficiency of an automated threshold algorithm, for detecting problematic moles.
Thus there is a need for a user-friendly mechanism for more fully exploiting collected image data for a region of interest within a larger image, and for commanding re-imaging of such a region of interest, to gather a more complete data set for the region.