Artifact = Green blip
Anomaly = White drawing of anomaly
Open up m_stalker.ltx and find the vision settings.
These are stalker_vision_free and stalker_vision danger, representing the two states NPCs reside in. Free, meaning they don't detect anything, danger meaning they do detect something and are in combat.
Further down the page we've got eye_range and eye_fov.
Eye range is how far they can see, and this is multiplied by the view distance settings near the top (min_view_distance and max_view_distance).
Eye FoV is their field of view. The larger the number, the wider the cone.
Next we've got visibility_threshold, which is how large the detection bar is (hidden in misery by default, but you've probably seen it before). The lower the number, the smaller the bar, and thus the faster they can detect you.
Related to visibility_threshold is time_quant, which is how fast that bar rises when you're being seen. Lower value = faster detection. Then we've got decrease_value, which is how fast the bar falls when break line of sight. Higher value = bar drops faster.
Then we've got always_visible_distance. At this distance, if the enemy is looking at you, even if they wouldn't otherwise be able to detect you, they can detect you. I don't know if it's a function of meters, or is a fraction of their modified eye_range, but we can drop it to 0 to remove it altogether since it's a shit effect and doesn't make any sense.
Next is luminosity_factor. The higher the value, the slower their detection is based on ambient light level.
Transparency_threshold is how well they can see through transparent objects such as bushes. The higher the value, the more their vision will be obstructed. Something around 0.9 completely stops them from seeing through bushes.
We've also got sound_threshold, which is how loud a sound needs to be before they detect it. Default for CoC is 0.08. Higher value = reduced hearing.