Sentence examples for a colour table from inspiring English sources
The first step of this scheme is to create a colour table, which covers all colours present in the original image.
The colour table generation in Step 1 of Figure 1 is the operation of collecting, without repetition, all the colours present in the original image in the raster scan order to create a colour table.
In [16], instead of using the entire colour space with colours as the codebook, a colour table containing only the colours present in the original image is first created.
Plotting viral fitness over γ allows us to rank the value of R0, i for each genotype at a given set of parameter values in order from lowest to highest, yielding a fitness ordering to which we assign a value and a colour (Table 3).
We use two -pixel images as examples, one with a large homogenous area (as shown in Figure 7(a)), thus a smaller colour table, while the other without a homogeneous background (as shown in Figure 8(a)), thus a larger colour table.
With a different colour table, the PEC algorithm will produce a greatly different clustering configuration and wrong ordering of the colours within each cluster, which will prevent the hidden data being extracted by the attacker. .
A large colour table means that every colour only appears a few times, indicating that there is no large homogenous area in the image, and vice verse.
Usually images with large homogeneous areas or low-frequency components lead to a smaller colour table than those images mainly consisting of high-frequency components.
Meanwhile, since the homogeneous background areas in an image only contain a limited number of colours, images with large homogeneous areas tend to have a smaller colour table, but greater rooms for cluster expansion.
(b) Because of the fragility of the PEC-based steganographic scheme, modifications on the stego-image will inevitably change the colours of the pixels and thus lead to a different colour table.
The cluster expansion operation results in an expanded colour table.
