Friends who like watching TV are familiar with these pictures on the cover, right? ! I remember when I was a child, most TV channels would look like these pictures every Tuesday afternoon. At the same time, some channels still play "old" music, which makes people crazy. Many people's first reaction must be to turn off the TV. In fact, this kind of picture is called TV test card, and its function is to help users adjust the TV picture, so that the TV can present the most standard colors and the clearest images. Below, the author will introduce the specific applications of these TV test cards in detail.