I have a 2D numpy array that I need to plot as an image with a certain scale. Within that image I need to be able to select a ROI or at least be able to display the mouse coordinates (of a specific target contained in the image). I tried using pyqtgraph but I can't seem to plot an image as a data source rather than just an image (i.e. can't seem to set axes, etc)... what would be the best way to do this, then? The image browser is compiled as a widget with a slider that scrolls through frames of the file; this widget is then embedded in a main window with a few table widgets.
I think imshow in matplotlib might work for you. It is easy to zoom, pan, and scale, and works easily with numpy.
(If this answer doesn't work for you, could you please refine your question. I'm unsure whether you're looking for any tool that will do the job, or something that works within the context of a gui that you've already implemented. If the later, I think you'll probably need to do the ROI yourself, by, say, selecting areas of the numpy array to plot, e.g. a[xmin:xmax, ymin:ymax].)
Related
Here is my snippet for both of them
from google.colab.patches import cv2_imshow
import cv2
pt = '/content/content/DATA/testing_data/1/126056495_AO_BIZ-0000320943-Process_IP_Cheque_page-0001.jpg' ##param
img = cv2.imread(pt)
cv2_imshow(img)
and here is the other one
import matplotlib.image as mpimg
pt = '/content/content/DATA/testing_data/1/126056495_AO_BIZ-0000320943-Process_IP_Cheque_page-0001.jpg'
image = mpimg.imread(pt)
plt.imshow(image)
Now, the image in second case is inverted
and image on my system is upright
What I am mostly afraid of is, if my ML model is consuming inverted image, that is probably messing with my accuracy. What could possibly be the reason to It and how do I fix it
(ps: I cannot share the pictures unfortunately, as they are confidential )
(Run on google colab)
All the help is appreciated
Your picture is upside-down when you use one method for reading, and upright when you use the other method?
You use two different methods to read the image file:
OpenCV cv.imread()
Mediapipe mpimg.imread()
They behave differently. OpenCV's imread() respects file metadata and rotates the image as instructed. Mediapipe's function does not.
Solution: Stick to OpenCV's imread(). Don't use Mediapipe's function.
The issue is not with matplotlib. When plt.imshow() is called, it presents the image with an origin in the top left corner, i.e. the Y-axis grows downward. That corresponds to how cv.imshow() behaves.
If your plot does have an Y-axis growing upwards, causing the image to stand upside-down, then you must have set this plot up in specific ways that aren't presented in your question.
I'm trying to create an iOS recoloring app (this is my reference), and i need to know how recolor some portion of the image when user taps on a given area. All the loaded pictures will be black/white initially.
Is there any prebuilt library? Or which graphics framework should i use?
Any help will be appreciated.
If what you are looking for is adding/replacing the colour within a certain shape and edges are really important (as in the example) then you should be looking into vectorised drawing.
What this means is every shape in your image would have an actual object representation in your code, and you could easily interact with that object to do whatever you want (i.e. tap gestures to change colour, zoom etc.).
This however, means that you can't simply use .jpeg images, and you need to use images in vector format, such as .svg or CorelDraw.
As a reference, check out SVGKit, which is an excellent library for working with SVG images.
I am trying to detect an object in a video. i am using SURF as feature detection and descriptor extractor, and BRUTFORCE as matcher. i tested my work with faces, i captured a picture of me and when i run the camera and direct it toward me, my face gets detected and a rectangle is drawn around it. i tried to make another test, i captured an image of my mouse and resized it, and when i run the cam, it is not getting detected
the problems i am facing are:
1-is the size of the query/object image matters in such cases,? i am asking this question because the image i captured of my self is bigger than the one of the mouse, and the face is getting detected and the mouse not.
2-regardless of which image i am using as a query/object iamge, how to display camera preview of only the train/scene image without the query/object image. i am asking this question because, what i am getting is something as shown in the below posted images, while what i want to do is something as it is shown here, i checked the code in that link, it is in C++ but i followed the same thing and also the tutorial uses 'drawMatches' method which has a peer in java which is Features2D.DrawMatches() and both of them returns a Mat object with the query/object image on the left side and the train/scene image on the right side as also shown in the image i posted below.
what i want to do is, to display on the the camera output without the query/object image, i want the area designated for the camera output is to show only the train/scene image captured from the camera.
please let me know how to solve this issues, i want to do something as shown in the tutorial i cited in the link.
1 - size matters but in your case, I think the most crucial problem is "textureness". SURF detect the interest points where the "texture gradient" is strong. In the case of your mouse, the gradient is mainly smooth, except aroud the logo (fujitsu), the button and at the border of the image. In the tutorial you point to, you notice it uses a very textured object to demonstrate the effect.
2 - to the best of my knowledge, there is fully automatic method to do what you want, but it can be done with a few steps. Basically, you must determine the surrounding box of your object then draw it. To draw, the easier is to use cv::rectangle but you can be more precise with four (or more....) cv::line. To determine the surrounding box, you can estimate the extreme points among the filtered matches.
Good luck!
Given a picture, I would like to modify it to create the effect of rain on glass. What steps should I take to achieve this goal?
Suppose we want to add the effect of a single drop of water on a given point in an image, some pixels around that point should be modified in some way: how these pixels should be modified?
Simple way is to just make transparent image that is actually image overlay. That looks like common approach of water drop effects in gimp.
example:
http://natural-drops.deviantart.com/art/drop-of-rain-373710307
I think that in order to make optically correct image one need to have full 3D info of environment, because most optics equations that one needs to simulate correct image includes each object distance.
I have two images that I want to display on top of each other. one image a single channel image and the second image is a RGB image but with most of the area being transparent.
How these two images are generated in different functions. I know to just display these on top of each other, i can use the same window name when calling cvShowImage() but this doesn't work when they are drawn from different functions. When trying this, I used cvCvtcolor() to convert he binary image from single channel to RGB and then displaying the second image from another function. But this didn't work. Both images are same dimension, depth and number of channels (after conversion).
I want to avoid passing in one image into the second function and then draw them. So I'm looking for a quick dirty trick to display these two images overlapped.
Thank you
EDIT:
I don't think that's possible. You'll have to create a new image or modify an existing one. Here's an article that shows how to do this: Transparent image overlays in OpenCV
There is no way to "overlay" images. cvShowImage() displays a single image from memory. You'll need to blend/combine them together. There are several ways to do this.
You can copy one into 1 or 2 channels of the other, you can use logical operations like AND, OR or XOR, you can use arithmetic operations like Add, Multiply and MultiplyScale (these operations will saturate values larger than 255). All these can also be done with an optional mask image like your blob image.
Naturally, you may want to do this into a third buffer so as not to overwrite your originals.
Apparently now it can be done using OpenCV 2.1 version
http://opencv.willowgarage.com/documentation/cpp/highgui_qt_new_functions.html#cv-displayoverlay