background luminance meaning in English

背景亮度
背景耀度，背景发光强度

This arithmetic divides the wavelet coefficients of carrier image into 27 - classes by the background luminance , the texture and the edge mask character of visual system ; then after encrypting watermark image with magic cube transformation , the ycbcr model is employed , it embeds the watermark sequences in the carrier image with different intensity according to the coefficients " classes of carrier image in y channel
首先，将载体rgb图像转换到ycbcr颜色空间，然后提取亮度通道y ，将其进行小波变换，然后利用人眼视觉模型对载体图象分解后的小波系数进行分类。其次，对有意义的水印图像分别进行3次不同的魔方置乱，得到3个随机水印序列。