OpenCV Python Tutorial For Beginners 21 - Image Pyramids with Python and OpenCV

[@greybandreg]

finally found the good explanation for image pyramid. good job

[@KevinskyChen]

Best openCV tutorial!!! Keep on bro

[@hermeticGreen]

for I in range(6) does NOT iterate 5 times....

[@elarbiamraoui8489]

last image is in index 6, not 5.. small inattention mistake because the array had an element before the for loop, aside from that, good work !

[@prabhakarkumar4750]

Yes. Thank you. At least somebody noticed that. I also think that is a mistake.

[@zoltantorok1189]

Hi, I've been following this playlist, and this is the first tutorial I had a problem with.
On the line "laplacian = cv2.subtract(gp[i-1], gaussian_extended)
" I get an error that reads:
Traceback (most recent call last):
File "[File Path]", line 20, in
[code mentioned earlier]
cv2.error: OpenCV(4.1.1) C:\projects\opencv-python\opencv\modules\core\src\arithm.cpp:663: error: (-209:Sizes of input arguments do not match) The operation is neither 'array op array' (where arrays have the same size and the same number of channels), nor 'array op scalar', nor 'scalar op array' in function 'cv::arithm_op'
What should I do to fix it? It's some sort of problem with cv2.subtract, because I get good results both for gp[i-1] and gaussian_extended. With the code from your website, I get the same error.
Thank you very much to anyone who knows what to do.

[@muhammadilyas2232]

this will solve the error
size = (gp[i - 1].shape[1], gp[i - 1].shape[0])
gaussian_extend = cv2.pyrUp(gp[i], dstsize=size)

[@SangNguyen-vt8jg]

@@muhammadilyas2232 OMG, thank you so much, I have been going through video forth and back but I didn't find any mismatch between my code and the code in video, I was getting crazy until I saw this comment. You saved my life, mate.

[@garethbale1008]

@@muhammadilyas2232 hey thank you very much!

[@saijetti7251]

@Muhammad Ilyas ,can u please explain the 1 st line of code

[@quocquoc4126]

@@muhammadilyas2232 thanks you so much!!!

[@cameronjordan897]

Thank you for all your help

[@jayshimpi1278]

you can fix the error by rectifying
gaussian_extended = cv2.pyrUp(gp[i],dstsize = (gp[i - 1].shape[1], gp[i - 1].shape[0]))
these parameter basically needs the size of the image,
I guess the updated version of python gives that error.

[@wete7641]

thanks bruder

[@AdiVasuDevaRao]

thank u so much

[@randalllionelkharkrang4047]

Why did you use a copy of the image instead of the variable containing the image ?

[@debjanichakraborty6947]

cv2_imshow(str(i), layer) this line is not working in google colab.
can anyone suggest how do I write this?

[@Nanda-ho5eh]

I'm getting this error. I'have copied the same code. Can anyone please help me out?? ---AttributeError: 'NoneType' object has no attribute 'copy'

[@elarbiamraoui8489]

you don't read any image, check the filename

[@vijaykumar-yq7sf]

Excellent

[@اسامةرائد-و8ذ]

Please i need the project in c# language 😭😭 who can get the code for c#

[@shashanksharmadon4295]

thanks bro.....

[@mohammadadil2847]

Awesome

[@delphinechatelain649]

Thx !!

[@fazlarabbi7049]

subtract error

[@mohammadyeasin6569]

subtract error is held for the difference of array size .to solve this add this line o code in the for loop, before caculating the gaussian extended.code-
size=(gp[i-1].shape[1],gp[i-1].shape[0])
my full code is-----------
img=cv2.imread('E:\practise\machine\datasheet for practise\img\muna.jpg')
img=cv2.resize(img,(712,712))
# lr1=cv2.pyrDown(img)
# lr2=cv2.pyrDown(lr1)
# lr3=cv2.pyrDown(lr2)
# hr=cv2.pyrUp(lr2)
layer=img.copy()
gp=[layer]
for i in range(6):
layer=cv2.pyrDown(layer)
gp.append(layer)
# cv2.imshow(str(i),layer)
layer=gp[5]
lp=[layer]
for i in range(5, 0, -1):
size=(gp[i-1].shape[1],gp[i-1].shape[0])


extended=cv2.pyrUp(gp[i],dstsize=size)
lap=cv2.subtract(gp[i-1],extended)
cv2.imshow(str(i),lap)
cv2.imshow('ug',layer)
cv2.waitKey(0)
cv2.destroyAllWindows()
i hope u understand

[@snowflakes003]

tough code! :(