Page 416 - Introduction to AI Robotics

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11.5 HIMM
reading 1 reading 2 399
00 0 0 0 00 0 0 0 00 0 0 0 00 0 0 0
00 0 0 0 00 0 0 0 00 0 0 0 00 0 0 0
00 0 0 0 30 0 0 0 30 0 0 0 60 0 0 0
00 0 0 0 00 0 0 0 00 0 0 0 00 0 0 0
00 0 0 0 00 0 0 0 00 0 0 0 00 0 0 0

reading 3 reading 4
00 0 0 0 00 0 0 0 00 0 0 0 00 0 0 0
00 0 0 0 00 0 0 0 00 0 0 0 00 0 0 0
60 0 0 0 63 0 0 0 63 0 0 0 66 0 0 0
00 0 0 0 00 0 0 0 00 0 0 0 00 0 0 0
00 0 0 0 00 0 0 0 00 0 0 0 00 0 0 0

reading 5 reading 6
00 0 0 0 00 0 0 0 00 0 0 0 00 0 0 0
00 0 0 0 30 0 0 0 30 0 0 0 33 0 0 0
66 0 0 0 56 0 0 0 56 0 0 0 55 0 0 0
00 0 0 0 00 0 0 0 00 0 0 0 00 0 0 0
00 0 0 0 00 0 0 0 00 0 0 0 00 0 0 0

reading 7 reading 8
00 0 0 0 00 0 0 0 00 0 0 0 00 3 0 0
33 0 0 0 33 3 0 0 33 2 0 0 33 2 0 0
55 0 0 0 55 0 0 0 55 0 0 0 55 0 0 0
00 0 0 0 00 0 0 0 00 0 0 0 00 0 0 0
00 0 0 0 00 0 0 0 00 0 0 0 00 0 0 0

Figure 11.11 HIMM updating for a series of 8 observations.

GROWTH RATE HIMM instead uses a companion mechanism called a Growth Rate Operator
OPERATOR or GRO to capture this heuristic.
Figure 11.12 shows the GRO and how it works. When an element g r[i][ i d
j
]
is updated with an occupied reading, GRO is applied as an extra step. The
MASK GRO uses a mask, W, to deﬁne “neighbors.” Masks are a common data struc-
ture in robotics and computer vision used to deﬁne an area of interest on an
array, grid, or image. The mask is literally a small array overlaid on the oc-

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