I am doing a fish counting project.
Can we use yolov object detection to detect objects (in this case fish) ONLY WHEN THEY CROSS A LINE ?
object detection after crossing a boundary line
Related
from what I know is that object detection uses both (Localization + Classification) but this only for binary classification
but what if I want to detect an object and its attributes?
For example, detect a face
if a mask is worn correctly return 0, if a mask worn improperly 1, otherwise 2
if the person eats return 0 otherwise 1
if the person smokes return 0 otherwise 1
what kind this problem is? and how can I annotate and train it?
I tried to use multi bounding boxes but I don't think it is a good idea
I have 2 shapefiles that represent roads, let's call them shapes A and B. Each road is represented as line segments. File B is almost a superset of the other, with just a few roads of A not represented. File A with one segment selected (in red):
In this superset file (B), the segments are smaller. I can say that for every segment in A there are one or more segments in B. I believe there isn't a segment in B that corresponds to more than one segment in A. Here is shapefile B with one segment selected (in red):
The line coordinates aren't exact, just very near each other. Here are the coordinates of the leftmost dot of the selected line:
Dot in file A: -42.92896076999995 , -22.77139965999993
Dot in file B: -43.217942900516830, -22.888565009926047
I'm using geopandas.
How would I cross-reference the two datasets? For each line segment in file B find the associated segment in file A (if it exists)?
The question seems to depend on what you are using as a standard for cross-references. For example, you must first decide whether to assume a case where each segmentation intersects or whether to define it as the minimum distance between each segmentation.
Anyway, using geopandas or shapely for both is not a difficult task. After dividing all the segmentation of A into individual linestrings, you can use the overlay function of geopandas to find the occurrence of even a slight intersection with the segmentation of B.
You will have to decide whether to find the shortest distance orthogonal or the shortest distance between the start point and end point of each segmentation. You can use from shapely.ops import nearest_points etc. You can use all the features of shapely to target the geometry of geopandas.
According to the help file
http://www.inside-r.org/packages/cran/igraph/docs/erdos.renyi.game
the erdos.renyi.game function is supposed to accept n=The number of vertices in the graph and m= the number of edges in the graph as input parameters.
The dataset I am working with has 6 vertices and 25 edges, so when i try
g = erdos.renyi.game(6,25)
I get an error
Error in .Call("R_igraph_erdos_renyi_game", as.numeric(n), as.numeric(type1), :
At games.c:569 : Invalid probability given, Invalid value
Not sure where I am going wrong, appreciate any advise on this topic.
Just use erdos.renyi.game(n=6, m=25) erdos.renyi.game(6, 12, type="gnm") and it will work. You have to define explicitly that the second parameter is for the value of m and not p.
erdos.renyi.game(n, p.or.m, type=c("gnp", "gnm"),
directed = FALSE, loops = FALSE, ...)
n
The number of vertices in the graph.
p.or.m
Either the probability for drawing an edge between two arbitrary vertices (G(n,p) graph), or the number of edges in the graph (for G(n,m) graphs).
type
The type of the random graph to create, either gnp (G(n,p) graph) or gnm (G(n,m) graph).
directed
Logical, whether the graph will be directed, defaults to FALSE.
loops
Logical, whether to add loop edges, defaults to FALSE.
...
Additional arguments, ignored.
Details
In G(n,p) graphs, the graph has ‘n’ vertices and for each edge the probability that it is present in the graph is ‘p’.
In G(n,m) graphs, the graph has ‘n’ vertices and ‘m’ edges, and the ‘m’ edges are chosen uniformly randomly from the set of all possible edges. This set includes loop edges as well if the loops parameter is TRUE. random.graph.game is an alias to this function.
Example:
g <- erdos.renyi.game(1000, 1/1000)
degree.distribution(g)
I am having trouble understanding ST_GeomFromText. It looks like there are 3 sets of 2 numbers. Why is that? Wouldn't coordinates just consist of a latitude and longitude?
Here is an example from http://postgis.net/docs/ST_GeomFromText.html:
SELECT ST_GeomFromText('LINESTRING(-71.160281 42.258729,-71.160837 42.259113,-71.161144 42.25932)');
ST_GeomFromText() takes a WKT expression of a geometry object and
Constructs a PostGIS ST_Geometry object from the OGC Well-Known text representation.
The WKT expression in the example is a LINESTRING which is
a one-dimensional object representing a sequence of points and the line segments connecting them.
You might think a linestring would be two-dimensional, but it's not, because a line has no width or height. (Points are 0-dimensional, polygons are 2-dimensional).
So, by definition, that would have more than one set of coordinates. A pair of coordinates would be a POINT, not a linestring, and would look something like this, in conjunction with the function in question:
ST_GeomFromText('POINT (30 10)');
You may want to read up on some GIS fundamentals:
http://www.cise.ufl.edu/~mschneid/Service/Tutorials/TutorialSDT.pdf - excellent tutorial
http://www.opengeospatial.org/standards/orm - OGC Reference Model
I've wrote a little wavefront's .obj file parser (3d model format), I'm able to display the geometry correctly but am having problems texturing it correctly.
The only way I'm able to get a correct texture is by dividing the model in my 3d editor, exporting and parsing it this way.. ie: I'm no longer sharing vertex data, each triangle is on it own so my indexBuffer's array looks like this [0,1,2,3,4,5,6...] which I want to avoid.
The correct texture/inefficient geometry (No reusing of vertices: 36 vertices):
Correct http://imageshack.us/a/img29/2242/textureright.jpg
Wrong texture/right topology (Sharing data: 8 vertices only = efficient):
Wrong http://imageshack.us/a/img443/6160/texturewrong.jpg
I thought to try and separate the UVs buffer from the indexBuffer destined to the vertices but didn't found a way to do it; if indeed it is doable.
I also messed with the agal code but haven't achieved any results.
The desired end is being able to pass different UVs coordinates to the same vertex in context of the triangle being drawn atm.
What to do?
Thanks. (I'm new to 3d programming)
It might seem like you need just one vertex per 'vertex location' of your model but, from what I understand of an .obj parser, you need to define your vertices around the FACES. This means you may have multiple vertices for some locations - depending on how many faces adjoin that location - but the pay off is you can have different UV coordinates for those vertices in the same location.
I'd suggest altering your parser to create vertices based on the faces they define rather than solely their positions. I know this bumps up the number of vertices but, from what I've read, it's unavoidable if you need different UVs for the same vertex location.
So, unfortunately, I'm pretty sure your first option is the way to go.
it seems like your welding operation is wrong. For welding vertices you must be sure that positions, UV-coordinates, normals and tangents(if you need them) are equal