28. An apparatus for identifying regions of text, the apparatus comprising: a memory storing an image of an environment outside the apparatus; means for checking whether a first block, which contains a first region of pixels that are contiguous with one another and comprising a local extrema of intensity in the image, satisfies a predetermined test, for presence along a line, of pixels with intensities binarizable to a common value; means for marking the first block as pixel-line-present, in the memory, when a result of the checking indicates the predetermined test is satisfied; means for identifying a second block that is located in the image adjacent to the first block, wherein at least the first block is marked as pixel-line-present; means for merging a first set of positions indicative of the first region of pixels in the first block with a second set of positions indicative of a second region of pixels in the second block to obtain a merged set of positions in a merged block, when a predetermined rule is satisfied by one or more geometric attributes of the first block and the second block; wherein the first region of pixels and the second region of pixels do not contact one another in the merged block; wherein the merging is performed prior to classification of any pixel in the first region of pixels and in the second region of pixels as text or non-text; and means for re-doing the checking with the merged block, to determine whether the merged block satisfies the predetermined test; wherein one or more of the means for checking, the means for marking, the means for identifying, the means for merging, and the means for re-doing comprise at least one processor coupled to the memory.
28. An apparatus for identifying regions of text, the apparatus comprising: a memory storing an image of an environment outside the apparatus; means for checking whether a first block, which contains a first region of pixels that are contiguous with one another and comprising a local extrema of intensity in the image, satisfies a predetermined test, for presence along a line, of pixels with intensities binarizable to a common value; means for marking the first block as pixel-line-present, in the memory, when a result of the checking indicates the predetermined test is satisfied; means for identifying a second block that is located in the image adjacent to the first block, wherein at least the first block is marked as pixel-line-present; means for merging a first set of positions indicative of the first region of pixels in the first block with a second set of positions indicative of a second region of pixels in the second block to obtain a merged set of positions in a merged block, when a predetermined rule is satisfied by one or more geometric attributes of the first block and the second block; wherein the first region of pixels and the second region of pixels do not contact one another in the merged block; wherein the merging is performed prior to classification of any pixel in the first region of pixels and in the second region of pixels as text or non-text; and means for re-doing the checking with the merged block, to determine whether the merged block satisfies the predetermined test; wherein one or more of the means for checking, the means for marking, the means for identifying, the means for merging, and the means for re-doing comprise at least one processor coupled to the memory. 29. The apparatus of claim 28 wherein: the predetermined test uses at least one peak in a profile obtained by projection of intensities of pixels along a direction, wherein a property of the at least one peak satisfies a predetermined condition identified in the predetermined test.