i am getting this error please help me ?

i=imread("Lena512.png")
i_i=im2double(i);
k=ones(4,4)/16;
b=1
conv2d(i_i,k,b)

function conv2d(i,k,b)
    [m,n]= size(k);
    [y,x]=size(i);
     y=y-m+1;
     x=x-m+1;
     ni=zeros(y,x)
       for l=2:1:y
           for j=2:1:x
                ni(l,j)=sum(i(l:l+m-1,j:j+n-1)*k)+b
           end
       end
end

Unable to perform assignment because the size of the left side is 1-by-1 and the size of the right side is 1-by-4.

Error in untitled2>conv2d (line 15)

ni(l,j)=sum(i(l:l+m-1,j:j+n-1)*k)+b

the respective pyhon code is working

# -*- coding: utf-8 -*-

"""

Created on Mon Oct 24 21:29:27 2022

@author: rishi

"""

import numpy as np

import cv2

import os

os.chdir(r"C:\Users\rishi\Downloads")

image=cv2.imread("Lena512.png")

image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

k=np.ones([4,4],dtype='int')/16

def convolution2d(image, kernel,bias):

m, n = kernel.shape

if (m == n):

y, x = image.shape

y = y - m + 1

x = x - m + 1

new_image = np.zeros((y,x))

for i in range(y):

for j in range(x):

new_image[i][j] = np.sum(image[i:i+m, j:j+m]*kernel) + bias

return new_image

x=convolution2d(image,k,bias=1)

cv2.imwrite('blurrey.jpg',x)

[Jan]

Is this the same question as https://www.mathworks.com/matlabcentral/answers/1833963-i-am-getting-this-error ? Then please delete one of them before somebody posts an anwer.