I have an assignent where i need to recreate the nearest neighbor interpolation function from scratch in python.
I just started the language a few days ago so i’m trying to write every little steps to achieve that.
This is my first try to solve it
The reasoning behind it is (for a given image and a scale of 0.5 for example) to scale the positions X and Y of the original image to X’ and Y’ like this:
Shape of the given image : 10x10.
I want to scale it to 5x5 (this is a downscaling)
X and Y positions before scaling
X and Y positions after scaling
Then i look up the pixels from the original image using those positions
I dont know if this make sense or i’m missing something
(the way i named my variables is not so great)
def interpolation_nn(image, scale): # saving the type of the image dtype = image.dtype #Adding padding to the image img_p = np.pad(img.astype(np.float32), 1) # Calculation of the size of the original image and of the interpolated image #Original img height,width = img.shape #interpolated image Scaled_width = np.floor(width * scale) Scaled_height = np.floor(height * scale) # Calculation of pixel coordinates in the interpolated image Scaled_X_coordinates=np.linspace(0.0, width, num=Scaled_width) Scaled_Y_coordinates=np.linspace(0.0, height, num=Scaled_height) #rounding my positions Scaled_X_coordinates=np.around(Scaled_X_coordinates) Scaled_Y_coordinates=np.around(Scaled_Y_coordinates) sys.stdout.write("Scaled_X_coordinates:"+str(Scaled_X_coordinates)+"\n") sys.stdout.write("Scaled_Y_coordinates:"+str(Scaled_Y_coordinates)+"\n") #edited finalMatrix= for Column in Scaled_X_coordinates.astype(int) : for Line in Scaled_Y_coordinates.astype(int) : Scaled_column = [image[Line-1,Column-1]] finalMatrix.append( Scaled_column ) #transfrom my array into an image finalMatrix = Image.fromarray(finalMatrix) #Does not work #returning a new matrix with the same type as the given img return finalMatrix.astype(dtype)
I have no idea how to look up into the pixels of the original image to recreate the new one having the new scaled positions. If something is unclear, please ask:)