Biomimetic. This term best describes the process in which we can slowly evolve our robots visual process and be able to compare our success with actual living organisms. Biomimetic simply means to "copy life" or one of its processes. We can use technology to mimic the function and behavior of an artificial life form such as a home built robot.
The simplest life forms on the planet are a great starting place for our research. Single celled bacteria for example can be photosensitive to light by becoming more active or triggering a feeding response. They don't think, they just react by chemical reflex. As you may remember from the Sweepbot 1 program, this robot had a simple photocell on the back of the processor board to do exactly this. In the morning when the sun came up, the robot wakes up and sweeps for 10 minutes. Then goes back to a sleep state and recharges until the next morning. So in this case, our last robot - the Sweepbot achieved in the visual sense full bacterium intellect.
A far more interesting single celled organism is a protist - the most sophisticated type of single celled life form called a Euglena. Here we can learn a great deal more on an animals ability to use a single photo receptor to control its more complex behavior. In this open file update, I will introduce you to three one eyed organisms, which use light sensitive spots rather than image forming eyes to perform lifes day to day activities. Then we will suggest some experiments for the Vision Logic Robot to emulate the visual intelligence of these animals and remove any doubt that we have achieved this level in the robot.
Let me first introduce you to Euglena.
The Euglena Protist:
Euglena, an animal so tiny you'll need a powerful microscope to see it clearly. But even at this size, it has one amazing feature few other protists have - an eye spot. Shown here as a two part assembly, the photo receptor itself, and an overlying pigment shield for bright light and UV protection. The single celled animal moves by a whip like structure called a flagellum, which propels it around like a tail of sorts. But remember one key point - Euglena HAS NO BRAIN. How can a simple animal such as this even interpret the information from the eye spot and respond accordingly without a brain? Euglena is telling us something very important here, which can define robotics vision at its simplest levels. More on that later.
Visual stimulus behavior
Euglena is a photosynthetic protist. In other words, it is unique in the animal kingdom in that it is half animal, half plant. The internal chloroplasts convert energy from the sun to sugars and foods for the Euglena when it is in the light, but Euglena can also consume smaller bacteria like an animal to survive as well. Because of the importance of a mobile organism to be able to move into the light to feed such as this, an eye spot evolved to assist its search for the strongest source of light. For a robot to achieve this level of intelligence, it must be able to home in on a single or extended light source with a single partially directional photo cell successfully. That will be the first experiment with the VLR (Vision Logic Robot).
Actual living Euglenas. The eye spot is the tan patch to the upper left end on both specimens.
Next let's examine Cyclops.
Case 2: Copepod Crustacean - "Cyclops"
Now lets move on to some more complex one eyed animals which have even more to show us. Lets start with a very tiny multicellular animal, smaller than the period on the end of this sentence, the Copepod. This tiny freshwater organism navigates its pond or shallow lake bottom using one eye as well. Its behaviors are more complex than Euglena because it has a very primitive nervous net and a crude swelling, or node at the front end of the animal - a primitive brain consisting of only a handful of cells. Because copepods have more complex joints, an exoskeleton and much more sophisticated sensors such as antenna and sensory hairs on its body, it can display complex behaviors and yet still only needs one eye spot to function.
Visual stimulus behavior
Cyclops feeds using its swimming antennas when it scoops up or bumps into a living food source such as green algae or small bacteria. It does NOT use its eye spot for hunting or food gathering. Cyclops does use its eye for day/night detection, and along with using a gravity sensor near its brain, it seeks the surface of the ocean or lake and goes up toward the light at the surface to feed in the warmest and richest waters. In other words it places it self in the maximum feeding benefit by seeking the bright surface.
A robot can emulate this visual level of intelligence by seeking a bright diffuse surface in a black surrounding and hovering in the vicinity of that surface while wandering and simulating the feeding process.
Next let's examine Artemia Salina.
Case 3: Crustacean Larva - "Sea Monkeys"
Finally, Id like to introduce to you an even more complex animal - Artemia Salina, known more commonly as brine shrimp. Only their underdeveloped larva have one eye, later the animals bilateral symmetry kicks in and two compound eyes develop. But at this stage this animal is famous for displaying a very well known behavior of photo sensitivity. You can hatch a jar full of these in dense saltwater in three days, and they will congregate all toward one side of the jar closest to the light. This behavior is a survival measure, it brings them to the surface to hide in the floating plant material which contains their protozoan food. While the young have only a very primitive nerve net and frontal nodal swelling you can barely call a brain, they too are perfect for an example of a very complex biological entity which performs all lifes functions on a single eye spot which forms no images.
Visual stimulus behavior
The pre adult, or naupila stage which has a single eye spot is of the most interest to us here. Brine shrimp normally swim around in their jar or salt lake surroundings in random patterns filling the area evenly dispersed in their surroundings. They do not normally gather. But put a flash light on one point in the jar, and nearly all of them will congregate so tightly in that spot you will only see a brown seething mass. It is an amazing sight.
For the VLR to accomplish a similar feat of intellect, it must first wander in a totally random manner in its arena. Then when a bright point of light is placed in the side of the arena, the robot must hover intensely right at that spot. When the light is removed, it will return to random dispersal.
Experiments and demonstrations for the "Cyclops" style robot:
1. Home in on on a bright point source of light then stop upon contact.
2. Home in on a bright point source and HOVER around the spot. Light off - random dispersal.
3. Head toward a bright diffuse surface and stop.
4. Head toward bright diffuse surface and HOVER next to that surface to simulate feeding.
5. Lights on (sunrise) become active, Lights off (sunset) become dormant.
6. Hide under rock experiment - Robot wanders until it finds itself in the dark under an overhang, then stops and hides.
7. Basking in the Sun experiment - Robot wanders until it finds itself under a bright lamp, stops to charge batteries.