Highlight image filter significantly improves optical character recognition on text images - Emerging Trends in Image Processing, Computer Vision, and Pattern Recognition - page 115

(7b)
(7c)
Figure 9 spots the two of the six possible cases shown in Figure 8 , showing the visual rep-
resentation of the situations when condition in Equation (7c) is met.
FIGURE 9 Possible cases for the condition in Equation (7c) to be fulfilled.
If the condition in Equation (7c) is not fulfilled, then the intensity of the Blue component will
be increased or decreased depending on whether the condition in Equation (8c) described be-
low is met or not. To be more specific, if the condition in Equation (8c) is fulfilled, the intensity
of the Blue component is decreased using a transformation in Equation (3) and in the oppos-
ite case, it is increased using transformation in Equation (4) . Both transformations are applied,
this time, regardless of the value of the Blue component:
(8a)
(8b)
(8c)