69 questions
5
votes
4
answers
139
views
Fast ways to count number of identical values in a row
I'm looking to count how many values in a row are identical. The idea is to be able to filter out respondents that have straightlined (ie answered all questions the same), for instance by filtering ...
- 107
-1
votes
2
answers
133
views
Finding a faint line in a very noisy image with variable background noise
I have a very noisy greyscale image where the noise level modulates along one axis. Within this image, there may be a very faint line of some unknown width. I want to be able to identify when this ...
0
votes
1
answer
526
views
Line Detection From Video Frames Using OpenCV
I have a laser pointer that projects red cross shape. My aim is to write a python code that detects those two projected lines from a video source. I use my mobile phone camera as a source and the ...
0
votes
1
answer
177
views
Line detection of noisy and blurry image
There is a noisy and blurry image that contains an edge that must be detected. The edge is clearly visible to the human eye, but I'm having trouble letting OpenCV detect it.
The image in question:
...
- 7
0
votes
1
answer
84
views
Detect, correct and optimize route for a straight route
There is a road which is mostly straight except for a few 90° turns. The road when converted to
coordinate system gives the following values.
point 1 0.00 1.41
point 2 0.71 2.12
point 3 1.41 2.83
...
- 25
0
votes
0
answers
170
views
How to find straight segments within an irregular curved line using R or QGIS
I have a shapefile (EPSG:4326 - WGS 84) containing many features with linestring geometries and I would really like to divide each line (like that one shown in the uploaded picture,example of ...
1
vote
0
answers
285
views
Detecting line inside a rectangle using OpenCV and Python
I have this image.Rectangles with lines.
I have to assign the number (1 to 4) below the image of the rectangle with respect to its length
inside the rectangle. The shorter the line lower the number. I ...
0
votes
0
answers
164
views
"Attempt to extract field 'point1' from 'mxArray'." error while trying to use "houghlines" command in MATLAB
I am using a matlab function block in simulink. Im trying to detect lines in a simulation. When I tried to use "houghlines" directly, it said that I need to use dynamic memory allocation. So ...
0
votes
0
answers
497
views
How can I separate lines in this text for OCR?
I want to use OCR on this block of text:
It works well on some lines, but on other lines it doesn't detect anything / gibberish. I'm pretty sure it's because of how the text is skewed, since if I ...
- 11
1
vote
1
answer
369
views
How can I combine HoughlinesP coordinates for a single line in OpenCV Python?
I'm using cv2.HoughlinesP to find the coordinates for each line in a document image. I'm getting 2 line coordinates when using HoughlinesP when there is only 1 line. How can I combine these two ...
- 13
0
votes
1
answer
275
views
How can I extract the thick line in this isometric view
I have a 2d drawing of a element (isometric view) as follow:
I would like to extract only the thick, longest black line (element with arrows embedded in it not dimensions) from it.
How to achieve ...
- 69
0
votes
0
answers
177
views
merging or removing duplicated lines on the border of an edge map
I'm trying to draw exactly one line on all the edges of an image. I was able to draw the lines but some of the lines are repeated and I'm stuck on it for days, any help would be appreciated. I tried ...
- 1
0
votes
1
answer
585
views
How to find the cordinates of the lines in this image?
I am new to OpenCV and I would like to know how to find the coordinates of vertical lines in an image. I do have a sample image
image
(This image is a row of a table. Since the data is sensitive i ...
- 1
0
votes
0
answers
72
views
I've been trying to apply Hough transformation for line detection on an image of rails. But I'm facing problems
'apply canny'
edges = cv2.Canny(gray, 200, 200)
plt.rcParams["figure.figsize"] = (100, 100)
plt.imshow(edges)
result = img.copy()
lines= cv2.HoughLines(edges, 1, math.pi/180.0, 170, np....
0
votes
0
answers
355
views
Find Specific straight lines in image with Python and CV2
I Have a specific image:
In this picture I try to detect the following lines reliable:
I tired to detect them with the following code:
def find_and_draw_lines(img):
# convert to grayscale
...
- 182
0
votes
1
answer
207
views
find if an device is in perpendicular to the current location from ariel view / map view
A device is traveling from source to destination and has support for GPS,
we are able to locate the nearest signal using (current loc - static fixed traffic signals array)
here D1 is nearest, but we ...
- 53
0
votes
0
answers
56
views
skimage.morphology does not contain Mediall_axis (python/ image process)
Dears,
my scikit, skimage does not contain medial_axis
Hence I get this below error while running
(python/ image process)
"medial_axis" is not defined
i tried uninstall and install skimage-...
0
votes
0
answers
693
views
Fit a straight line on curve in image with OpenCV
I am trying to detect a straight line on an image containing a not so straight line using OpenCV python.
For example in this image, we can see there is a somewhat horizontal line.
I have tried using ...
- 25
3
votes
1
answer
6k
views
Extract lines from image with python
I need to extract path/lines from an image. I apply laplacian filter to this input. In laplacian filtered image, the lines to be extracted can be seen as low value pixels connected to form a linear ...
- 33
1
vote
0
answers
1k
views
How to find intersection of lines with opencv
In this picture, I try to fin intersection points between the long white lines between racing lanes and the short perpendicular ones
So to automaticaly obtain the black points as materialized below
...
- 47
0
votes
0
answers
61
views
why the output window cannot display the result. Image processing - line detection
this Hough Transform program is supposed to display the source image, output image, edge detection results windows with images when executed.
However, the output image window is not displaying ...
- 1
0
votes
1
answer
724
views
Find vertical 1px lines with OpenCV
I have an image something like the image below (on the left):
I want to extract only the pixels in red on the right: the pixels that belong to a 1px vertical line, but not to any thicker line or ...
- 6,430
1
vote
1
answer
2k
views
I have using opencv python form converting the analog clock to a digital data for the hours and minutes but I need it to show for seconds too
I have ued opencv to read the image , convert it to gray scale, and found edges using canny, kernel, thesh, erode and so on and i have detected all the lines in the image using HooughLineP() and i ...
- 55
0
votes
1
answer
137
views
How to detect a grainy line?
I am trying to detect a grainy printed line on a paper with cv2. I need the angle of the line. I dont have much knowledge in image processing and I only need to detect the line. I tried to play with ...
- 1
0
votes
0
answers
69
views
How can I determine co-ordinates of the lane?
I am using opencv to determine coordinates the lane between two red lines like this:
Lane-detection:
It is not rectangle so I can't use cv2.rectangle to cover on it.
Does everyone have some ideas?
- 1
2
votes
2
answers
224
views
Hough Transform algorithm for pattern recognition of straigth lines form points
Hello everyone, I'm currently working on different algorithms which could give me the patterns of straight lines within groups of aligned cells.
Let me explain:
Suppouse we have a XY plane which is ...
- 23
0
votes
1
answer
235
views
Line detection issue - OpenCV in Python
I have written the following script with which I aim to detect lines in Gazebo (a simulation environment):
#!/usr/bin/env python
# rospy for the subscriber
import rospy
# ROS Image message
from ...
0
votes
1
answer
398
views
How to detect all the verticle background lines using Probabilistic Hough lines transform?
I'm trying to detect background lines of a pre-processed binary image of a newspaper article using Hough lines transform.
The code I used is given below and it detects only one vertical background ...
- 517
0
votes
1
answer
266
views
Extract straight lines from a 2D binary matrix
I would like to extract straight lines from a 2D binary matrix.
256x128 matrix
I would to find 1s grouped by neighbor coordinates.
In the attached image, there is a 256x128 binary matrix.
4 straight ...
- 21
0
votes
1
answer
394
views
How to find multiple horizontal straight lines in a scatter plot using MATLAB?
Hi,
I have a set of points (scatter plot). I am interested in finding multiple (approximately) horizontal straight lines (or clusters) in this data. For example in the image attached, I have drawn ...
- 29
0
votes
2
answers
382
views
Plotting a point on straight line
The equation of a line is Y = M.X + C,
I have a point and the points facing angle, So I can work out the line equation
Slop := Tan(Rot) // We are passing radians to convert to gradient
C := (-Slop*X)...
- 139
0
votes
0
answers
201
views
Line Endpoint Detection in OPENCV
I would like to find enpoints of lines in my image and then connect them to fix line breaks. The blue part in the image are the line breaks I would like to fix. The green part is the houghline ...
0
votes
1
answer
309
views
How to discriminate between lines in CV2 image processing with python?
I am working on a skeletal formula image processor in python as a chemistry project. It is still in its very early stages, but I've been stumped by a problem. When I run the image processing, singular ...
- 23
2
votes
3
answers
2k
views
Fitting a straight line on a part of a dataset [duplicate]
I am working on a problem that needs best fit line, though the best fit should be applied on initial part of the data and not the whole datapoints.
I know how to curve-fit a function on a dataset when ...
- 349
1
vote
1
answer
1k
views
Hough transformation calculation
hough transformation using the normal equation of a line.
For calculating the value of r while keeping the values of x and y same for different θ the following formula is used.
r = sin(θ)y + cos(θ)x
...
- 153
2
votes
1
answer
606
views
I have an issue while drawing the lines over an image using pair of coordinates using opencv python
I have a set of coordinates from an image. Using those coordinates I wanted to plot the lines over an image. While trying I ended up with an error. Please help me with this issue. Below is the code.
[...
- 57
2
votes
1
answer
4k
views
How to count lines in an image with python, openCV
I want to count paper, so I am thinking about using line detection. I have tried some methods like Canny, HoughLines, and FLD. But I only get the processed photo. I have no idea how to count it. There ...
- 21
2
votes
1
answer
2k
views
python function to find local maxima/peaks from array
i am trying to detect local maxima from a given array. The array is a sinusoidal curve obtained after calculating hough line transform. Here is the image
Here is the numpy file accumulator.npy. ...
- 149
1
vote
1
answer
629
views
How to detect straight lines on grayscale images？
I have some grayscale image，one of which is shown following：
This image is like a “disk” which contains a lot of noise in the non-black area. I want to detect the line in it. The line is easy to be ...
- 13
4
votes
1
answer
6k
views
How to remove all the detected lines from the original image using Python?
I am trying to remove all the lines present in the image.
I am able to detect the lines but when I am trying to remove the lines, I am still getting few small lines in the final image. I have used cv2....
- 315
0
votes
0
answers
92
views
how to find straight line which passes throught most number of points?
Suppose I have (x,y,z) scattered random points. I want to find a straight line which passes through most number of data points and if many occurs then what is the maximal length of this straight line. ...
- 311
0
votes
0
answers
67
views
what is the simplest/most efficient way of detecting black lines in image?
I have a collection of signal images with
signal as a black line, grid of red lines in the background, and black letters and numbers that are of no importance to me.
I need to extract the black ...
- 165
3
votes
1
answer
782
views
How to perform image segmentation on white lines in a green field/grassy field
As the title states I'm attempting to do image segmentation in hopes of doing 'lane' detection. Here is a sample image I want to test on.
Here's my first coding attempt for what I tried that I found ...
- 171
1
vote
1
answer
540
views
How to detect all the separation lines in image in xamarin or c# or python?
I need to detect all the lines (edges) in an image an their positions in my xamarin application .
like in the image attached .
I have tried openCV in python but still I did not get all the lines , I ...
- 151
7
votes
2
answers
11k
views
Extract vanishing point from lines with Open CV
I'm working on OpenCV based project in python, and I have to calculate/extract and show visually the vanishing point from existing lines.
My first task is to detect lines, that's very easy with Canny ...
- 631
0
votes
1
answer
2k
views
Arcs and line segments detection from collection of points
I am preparing to create a program to detect arcs and line segments from the collection of points (x,y) which follow each other and generally, they create a closed polygon.
I just dont know where to ...
- 395
4
votes
0
answers
3k
views
Opencv - python - Join line segments from Line Segment Detector (LSD) to form one line
I am working on this problem of finding popping crease of the cricket pitch and I have somewhat achieved what I wanted to do that is I can detect vertical line segments using LSD from opencv but what ...
- 364
1
vote
0
answers
237
views
Finding out number of straight lines and curves in a given edge (canny or sobel) image
I have tried the Hough algorithm for straight lines, but it only detects outermost frame of image (most of the time as square). All the internal information is left out.
I actually want to count(...
- 29
1
vote
0
answers
393
views
How to identify lines, starting point and ending point of each line in a floor plan using opencv?
I am creating a tool to generate 3d model of a house by analyzing its floor plan. Up to now i was able to isolate all the wall of a floor plan.
Original Floor Plan :-
Isolated Walls :-
Then I tried ...
- 768
1
vote
0
answers
1k
views
Football field line detection
I wanted to create a model which can detect penalty area field lines.
I managed to get desirable results for one specific image by changing some hyperparamaters, but the same code doesn't work for ...
- 23