LiDAR can't make that SciFi "X-Ray" things. LiDAR is Light Detection and Ranging. $10 ToF laser ruler is a basic LiDAR. It measure distance to the reflecting object. Measuring distances to different points of oblect will make 3D "point cloud". This could be automated with few tricks, like moving mirrors. LiDAR scanner price depends on range, longer range you need, more powerful laser you need. Simple LiDAR for robot vacuum cleaner is less than $100 on Aliexpress. Fine for a room, but useless for scanning mountain. $25k looks like a decent price for a LiDAR that could scan a mountain.
You can't measure distance to something that is behind or inside something opaque. Obviously. Light can't pass through opaque things.
To find and picture underground cavern you need acoustic sensors mesh and some explosives. Echolocation in sophisticated form and all that stuff. You put a lot of acoustic sensors evenly around place you want to explore, then detonate something to produce large acoustic wave in the ground. "Fire in the hole" - and collect signals from sensors. Acoustic wave from explosion would reflect from cavities and junctions of different mineral, kind of echo. Sensors will get one large spike of explosion and lower spikes for reflections. Time between explosion and echoes means distance. Analysing this data from all that mesh of sensors in different places you could restore some image that could depict something interesting. However, it will not be a perfect image like on above pictures, in the best case you will get something like ultrasound image of your guts. :) This have nothing to do with LiDAR. And it will cost much more than $25k.
LiDAR can't make that SciFi "X-Ray" things. LiDAR is Light Detection and Ranging. $10 ToF laser ruler is a basic LiDAR. It measure distance to the reflecting object. Measuring distances to different points of oblect will make 3D "point cloud". This could be automated with few tricks, like moving mirrors. LiDAR scanner price depends on range, longer range you need, more powerful laser you need. Simple LiDAR for robot vacuum cleaner is less than $100 on Aliexpress. Fine for a room, but useless for scanning mountain. $25k looks like a decent price for a LiDAR that could scan a mountain.
You can't measure distance to something that is behind or inside something opaque. Obviously. Light can't pass through opaque things.
To find and picture underground cavern you need acoustic sensors mesh and some explosives. Echolocation in sophisticated form and all that stuff. You put a lot of acoustic sensors evenly around place you want to explore, then detonate something to produce large acoustic wave in the ground. "Fire in the hole" - and collect signals from sensors. Acoustic wave from explosion would reflect from cavities and junctions of different mineral, kind of echo. Sensors will get one large spike of explosion and lower spikes for reflections. Time between explosion and echoes means distance. Analysing this data from all that mesh of sensors in different places you could restore some image that could depict something interesting. However, it will not be a perfect image like on above pictures, in the best case you will get something like ultrasound image of your guts. :) This have nothing to do with LiDAR. And it will cost much more than $25k.