$(1)$ As shown in Figure $1,$ suppose we have a color image with a resolution of $2\backslash$times $2$ pixels.Each pixel has $24$ bits representing red $(8$ bits$),$ green $(8$ bits$)$ and blue $(8$ bits$)$ respectively.However, we notice that humans are more sensitive to Red and Green than to Blue $-$ in fact, $1\mathrm{.}5$ times more sensitive to Red and Green than to Blue.