Question

Please design the function in version 3 of python

4. Write a function extract(pixels, rmin, rmax, cmin, cmax) that takes the 2-D list pixels containing pixels for an image, and that creates and returns a new 2-D list that represents the portion of the original image that is specified by the other four parameters. The extracted portion of the image should consist of the pixels that fall in the intersection of the rows of pixels that begin with row rmin and go up to but not including row rmax the columns of pixels that begin with column cmin and go up to but not including column cmax. For example, if you do the following: pixels - load_pixels('spam.png' extracted extract(pixels, 90, 150, 75, 275) save-pixels(extracted, 'extract spam.png) extract_spam.png saved. you should obtain the following image: SPAM Notes/hints: Here again, your function will need to create and return a new 2-D list of pixels, and you can use the blank_image) function for that purpose. Compute the dimensions of the new image from the inputs to the function. - Don't forget that the rmax and cmax parameters are exclusive, which means that the extracted image should not include pixels from row rmax or column cmax of the original image. This is similar to what happens when you slice a string or list, and it should make it easier to compute the dimensions of the image. One way to solve this problem is to use nested loops to iterate over the rows and columns of the newly created 2-D list-the one that represents the extracted image. You can then perform the necessary computations on your loop variables r and c to determine the cooordinates of the pixel from the original image that you should use for the pixel at position (r, c) in the new image. Use concrete cases to determine the appropriate computations. def create_uniform_image(height, width, pixel): """ creates and returns a 2-D list of pixels with height rows and width columns in which all of the pixels have the RGB values given by pixel inputs: height and width are non-negative integers pixel is a 1-D list of RBG values of the form [R,G,B], where each element is an integer between 0 and 25!5 pixels - for r in range(height): row - [pixel] * width pixels +- [row] return pixels def blank_image(height, width): "" creates and returns a 2-D list of pixels with height rows and width columns in which all of the pixels are green. inputs: height and width are non-negative integers all_green - create_uniform_image(height, width, [0, 255, 0]) return all_green def brightness(pixel): """takes a pixel (an [R, G, B] list) and returns a value between 0 and 255 that represents the brightness of that pixel red -pixel[0] green pixel[1] blue -pixel[2] return (21*red 72*green 7*blue) // 100

Answer 1

def extract(pixels,rmin,rmax,cmin,cmax):
  
'''
  
This function return the extracted image.
  
It simply loops over required rows and columns
and stores the result in another list which is
returned.
  
'''
  
ans=[]
for i in range(rmin,rmax):
row=[]
for j in range(cmin,cmax):
row.append(pixels[i][j])
ans.append(row)
  
return ans