METHOD FOR COMPRESSING VIDEO SIGNAL

PURPOSE:To compress the level of a video signal so that an input level (y) becomes smooth in the neighborhood of a knee point KP. CONSTITUTION:The input level (y) and the level of the knee point KP are compared. When (y)=KP, level difference (y-KP) detected by a level detector 5 is converted to data which smoothly increases corresponding to the level difference by using the look up table of ROM7. When the input level (y) is over a knee curve end point KE, a maximum value is outputted from ROM7. Then, an adder 10 adds a value obtained by multiplying the level difference (y-KP) by (k) times with a multiplier 8, a value obtained by multiplying the output value of ROM7 by (1-k) times with a multiplier 9 and the knee point KP.