Chroma sub-sampling is widely used by many video recorders to remove color redundancies. Table 1 shows an array of raw video pixels before sub-sampling. Each pixel is represented by Y/Cb/Cr. 61/21/12 71/31/13 81/41/14 91/51/15 Table 1 - YCbCr array (for example, 77/61/62 means, for this pixel, Y=51,Cb-61,Cr=62) (i) 61/21/12 71/31/13 81/41/14 91/51/15 (ii) 61/21/12 71/31/13 81/41/14 91/51/15 61/21/12 71/31/13 81/41/14 91/51/15 Apply 4:20 and 4:1:1 chroma-subsampling schemes to Table 1 and show their results respectively. (6 marks) Using HVS characteristics and image data characteristics shown in Table 1. discuss why chroma sub-sampling is used. (4 marks)