how can i get all the pixels that belongs to a specific instance in the image in cityscapes dataset?
i wanted to mask out an instance from the original image :
https://tillbeemelmanns.github.io/assets/images/convert-cityscapes-to-coco/preview.png
to this :
https://i.ibb.co/g4XQfv1/city-to-coco-1.jpg
is there anyway to extract these pixel directly from the instances id in cityscapes dataset ?
Thanks in advance.
Related
How can I let resliceimageviewer display a colored image? I know that vtkResliceImageViewer can setup lookup table. But I need to blend two images after map image to color.
I use DICOM reader to read image data. Then I create a lookup table to change image data into RGBA. Next I blend image with a mask to display the region of interst. Everything works fine except vtkResliceImageViewer can’t display color. Can someone help me?
Or does someone know how to create a Lookup table that output origin image?
I want to calculate the color histogram of an image but only taking into account specific pixels (whose 2D coordinates I know).
Is it possible to use calcHist specifying that only these concrete pixels should be taken into consideration (instead of the whole cv::Mat and all the pixels in it)? If not, is it possible to create a new Mat including only those specific pixels at known positions, and how? (Considering that for a histogram the pixel coordinates do not matter, could they be added to a (1 x number_of_specific_pixels)-dim Mat keeping the original type of the Mat?)
Thanks a lot in advance!
The third parameter of clalHist is called Mask.
So, you create a new single channel 8 bit cv::Mat that has the same size of your input image. It should contain 255's where you want to calculate the histogram and 0's where you do not. Then, pass it as Mask.
I am doing a project where i need to find a red laser dot. After changing to HSV color space model and thresholding individual H,S,V components and merging it , i found a laser dot with several noise as well , now i need to subtract all other image components except for the laser dot and the noise with their respective color so that i can process those frame for further processing like template matching to get only the laser dot reducing the noises. Hope you understand the question and Thank You, any similar help is appreciated.
What you're looking to do is apply a mask to an image. A mask is an image where any positive non-zero value acts as an indicator. What you want to do is use the mask to indicate which pixels in the original image you want.
The easiest way to apply a mask is to use the cv2.bitwise_and() function, with your thresholded image as the mask:
masked_img = cv2.bitwise_and(img, img, mask=thresholded_img)
As an example, if this is my image and this is my mask, then this would be the masked image.
I have a black area around my image and I want to create a mask using OpenCV C++ that selects just this black area so that I can paint it later. How can i do that without affecting the image itself?
I tried to convert the image to grayscale and then using threshold to convert it to binary, but it affects my image since the result contains black pixels from inside the image.
Another Question : if i want to crop the image instead of paint it, how can i do it??
Thanks in advance,
I would solve the problem like this:
Inverse-binarize the image with a threshold of 1 (i.e. all pixels with the value 0 are set to 1, all others to 0)
use cv::findContours to find white segments
remove segments that don't touch image borders
use cv::drawContours to draw the remaining segments to a mask.
There is probably a more efficient solution in terms of runtime efficiency, but you should be able to prototype my solution quite quickly.
I want to create a secondary capture DICOM file as per the requirements.
I created one, but the image( pixel data in the tag 7FE0 0010 ) looks distorted. I am reading a JPEG image using Gdiplus::Bitmap and using API ::LockBits and 'btmpData.Scan0' to get the pixel data. The same is inserted into the pixel data tag - 7FE0,0010. But while viewing the same in a DICOM viewer, it is coming as distorted. The dicom tags Rows, Columns, PlannarConfiguration are updated properly. BitsAllocated, BitsStored and HighBit are given values 8,8 and 7 respectively.
While goggling I came to know that, instead of RGB format, the bits might be in the order BGR. Hence I tried to switch the bits in the place 'B' and 'R'.
But still the issue exist. Could anybody help me ?
Apparently you forgot to take into account Stride support from GDI+. An image being much more explicit than 1000 words here is what I mean:, the actual full article being here.