Question about path planning.

[JeremyLinky]

Hi, I visualize the "wall" in collision map (plot in orange), and the planning path (plot in purple), finding that the path can sometimes still across the "wall". I don't know why. Can you provide some reasons for that? Much appreciate!

[srama2512]

Hi. Thank you for your question. The colorscheme of the map (see Fig. 5 here) is:

• Dark and light green are regions classified as occupied by the model.
• Gray and purple are regions classified as free by the model.
• When compared to the ground-truth map, the light green and gray predictions are incorrect. Dark green and purple are correct predictions.

Here, the model thinks that the gray area is free (eventhough it isn't). So it plans through it.

[JeremyLinky]

Hi. Thank you for your question. The colorscheme of the map (see Fig. 5 here) is:

• Dark and light green are regions classified as occupied by the model.
• Gray and purple are regions classified as free by the model.
• When compared to the ground-truth map, the light green and gray predictions are incorrect. Dark green and purple are correct predictions.

Here, the model thinks that the gray area is free (eventhough it isn't). So it plans through it.

Thanks for your reply! But it seems that you haven't figure out my question. My question is why can the planned path pass through the obstacle after the obstacle is set in front of the agent on the collision map? The obstacles are drawn in orange and the planned path is drawn in dark purple as below.

[srama2512]

Oh, sorry about that. I misunderstood the question. This is interesting. Could you provide more details about how the orange lines were generated, and confirm whether the updated map is sent to the planner or not?

[JeremyLinky]

Oh, sorry about that. I misunderstood the question. This is interesting. Could you provide more details about how the orange lines were generated, and confirm whether the updated map is sent to the planner or not?

1. The orange lines represent the obstacle in front of the agent if a collision happens. It is from your original code:

And I just plot the points set as 1 in the collision map as below.

2. I think the updated map is sent to the planner since the planner is behind updating the collision map:

Also, I plot the global map after self._process_maps( ), finding that the obstacles are indeed updated in the map:

[srama2512]

Thank you for providing the details. This sounds about right. Can you also share how you are plotting the planner outputs?

[JeremyLinky]

Thank you for providing the details. This sounds about right. Can you also share how you are plotting the planner outputs?

Thanks for your reply. I save the path in function _compute_plans_and_local_goals( ) as below.

And I plot it like:

[srama2512]

It looks like the issue might be happening within the planner rather than the ActiveNeuralSlamExplorer. Is it possible for you to share the planner map (the purple and yellow map), start and goal positions with me? I can run the planner locally and check what the issue is.

[JeremyLinky]

It looks like the issue might be happening within the planner rather than the ActiveNeuralSlamExplorer. Is it possible for you to share the planner map (the purple and yellow map), start and goal positions with me? I can run the planner locally and check what the issue is.

Thanks for your kind reply! Here, I provide the global_map、global_map_proc、goal_map_xy、agent_map_xy for you in a ".npz" file as the form of numpy array . These variables appear in the following locations when they are saved :

You can first unzip the following file and then use x=np.load('./result.npz',allow_pickle=True) to load it as x. If you want to read the global_map, you can then use keys "global_map" like x['global_map'], so as to other variables. result.zip

Here I also provide the map without the planned path and the map with the planned path as follows. Green represents occupied or obstacles, black represents free space or unknown space, and red represents the planned path. It may not be easy to see the planned path clearly, you can enlarge the second picture slightly in order to see it.

Looking forward to your reply!! Much appreciate!!

[srama2512]

Hi @JeremyLinky , sorry about the latency on this issue. I tried running pyastar.astar_planner on the map you sent. The result I got makes sense (see below). I'm not sure where exactly your issue is coming from. My intuition is that the (x, y) conventions may have been incorrect somewhere along the way. Could you please check this once and let me know?

Here is the code to reproduce this:

import cv2
import pyastar
import numpy as np

x = np.load("./result.npz", allow_pickle=True)

global_map = (x["global_map_proc"][0] * 255.0).astype(np.uint8)
global_map = np.repeat(global_map[..., np.newaxis], 3, axis=2)

global_map = cv2.circle(global_map, tuple(x["agent_map_xy"][0].astype(np.int32).tolist()), 4, (255, 0, 0), -1)
global_map = cv2.circle(global_map, tuple(x["goal_map_xy"][0].astype(np.int32).tolist()), 4, (0, 255, 0), -1)

# Perform planning
agent_xy = x["agent_map_xy"][0].astype(np.int32)
goal_xy = x["goal_map_xy"][0].astype(np.int32)
path_x, path_y = pyastar.astar_planner(x["global_map_proc"][0], agent_xy, goal_xy, allow_diagonal=True)

# Draw path
for x, y in zip(path_x, path_y):
    global_map = cv2.circle(global_map, (x, y), 2, (127, 127, 127), -1)

cv2.imshow("Global map", global_map[..., ::-1])
cv2.waitKey(0)

[JeremyLinky]

Hi @JeremyLinky , sorry about the latency on this issue. I tried running pyastar.astar_planner on the map you sent. The result I got makes sense (see below). I'm not sure where exactly your issue is coming from. My intuition is that the (x, y) conventions may have been incorrect somewhere along the way. Could you please check this once and let me know?

Here is the code to reproduce this:

import cv2
import pyastar
import numpy as np

x = np.load("./result.npz", allow_pickle=True)

global_map = (x["global_map_proc"][0] * 255.0).astype(np.uint8)
global_map = np.repeat(global_map[..., np.newaxis], 3, axis=2)

global_map = cv2.circle(global_map, tuple(x["agent_map_xy"][0].astype(np.int32).tolist()), 4, (255, 0, 0), -1)
global_map = cv2.circle(global_map, tuple(x["goal_map_xy"][0].astype(np.int32).tolist()), 4, (0, 255, 0), -1)

# Perform planning
agent_xy = x["agent_map_xy"][0].astype(np.int32)
goal_xy = x["goal_map_xy"][0].astype(np.int32)
path_x, path_y = pyastar.astar_planner(x["global_map_proc"][0], agent_xy, goal_xy, allow_diagonal=True)

# Draw path
for x, y in zip(path_x, path_y):
    global_map = cv2.circle(global_map, (x, y), 2, (127, 127, 127), -1)

cv2.imshow("Global map", global_map[..., ::-1])
cv2.waitKey(0)

Thank you for your patience! I took a closer look at the codes of the project, and found that before sending the map to the path planning, it also cropped the processed map in the codes. I guess this is the problem.

The a algorithm is completely fine, but before handing over the map to the a algorithm, it crops the map around the midpoint of the line connecting the agent position and the goal point position as the center, and reserves a 3m wide space on the boundary, which is set as a free space, as shown by the blue circle in the figure below( the green represents the cutting position without reserved space, and the red represents the cutting position after 3m of space is reserved ). This resulted in the place where the obstacles at the boundary originally being set up as free space, the A* algorithm will plan the path to pass through, and finally displayed on the uncropped map becomes the planned path through the obstacle .

The curve in the figure below is roughly drawn by me with a brush, but it does not affect what I want to express. The orange line represents the approximate direction of the path I found to pass through the obstacle. You can refer to my last answer.

If you have time, you can run the source code of your project to verify that my statement is correct, much apperciate!

The source code is as follows.

[srama2512]

This totally makes sense. Yes, I added the padding outside there to prevent the agent's plans from completely failing due to the cropping. However, this is an approximation which was needed to finish evaluating within the time-limits for the habitat challenge. If computational time is not a concern, I would recommend planning on the full map. Please feel free to close the issue if this resolves it.

[JeremyLinky]

Thanks for the kind reply !!