Under normal circumstances, the distance of 20 meters may not be able to clearly capture the details on the small note for ordinary surveillance cameras. The pixel and focal length of the surveillance camera will affect the clarity of the image. If the pixels of the camera are high enough and the focal length is appropriate, you may be able to see the words or details on the small note. However, it should be noted that lighting conditions and camera quality will also have an impact on capturing details. Generally speaking, whether you can read the note clearly depends on the specific surveillance camera and the actual situation.