How are numerous small indications on the display screen described?

The description of numerous small indications on the display screen as "hash" is appropriate because in ultrasonic testing, hash refers to a pattern of scattered noise or artifacts that appear as multiple small, random signals. This phenomenon usually occurs due to various factors such as the inherent characteristics of the material being tested, surface conditions, or electronic noise in the testing equipment.

In the context of ultrasonic testing, hash can often complicate the interpretation of the signals during an inspection, as it makes it difficult to distinguish valid indications from random noise. Understanding that these small indications represent hash allows technicians to apply appropriate techniques to filter or discriminate between meaningful echoes and background noise, enhancing their ability to accurately assess the integrity of the material or weld being inspected.