Effect in the output image for the transformation functions

Answer 1

[KALYAN ACHARJYA]

Figure 1

No effect

Figure 2

%Approximate
Output_image=Input_image-L/2;

or

output_image=slope*input_image+(-c)  % Decide C as per figure

Figure 3

Divide in 3 zones and do the same as Figure 2

Figure 4

Same as figure 2, change the slope and c

See the contrast stretching or gray level transfomation topics (Golzalez Book)