點圖由正面和背面的兩個不同的圖表組成。
其中一個有31行的點和其他15行的點。 它們可用于確定失真和色差。
The dot chart consists of two different charts on the front side and the back side.
One of them has 31 lines of dots and the other 15 lines of dots. They can be used to determine distortion and chromatic aberration.