How to correct the following error in MATLAB? MATLAB code follows: Error using horzcat

Dimensions of arrays being concatenated are not consistent.

Error in Rev$2($line $49)$

generatorMatrix $=[$eye$(4)$ parityMatrix'$]$; clc;

clear all;

$\%$ Load the lenna image

lenna $=$ imread$(\text{'}$lenna$.$png$\text{'})$;

$\%$ Convert image to grayscale

lenna$\_$gray $=$ rgb$2$gray$($lenna$)$;

$\%$ Convert pixel values to bits

lenna$\_$bits $=$ reshape$($de$2$bi$($lenna$\_$gray$),[],1)$;

$\%$ BPSK modulation

Eb$\_$No$\_$low $=0$; $\%$ Low SNR

Eb$\_$No$\_$high $=4$; $\%$ High SNR

SNR$\_$low $=10^($Eb$\_$No$\_$low$/10)$;

SNR$\_$high $=10^($Eb$\_$No$\_$high$/10)$;

$\%$ Transmit and receive at low SNR

received$\_$low $=$ awgn$($double$($lenna$\_$bits$),$ SNR$\_$low, 'measured'$)$;

$\%$ Demodulation

decoded$\_$low $=$ received$\_$low $<0$;

$\%$ Reshape decoded bits to original image size

decoded$\_$image$\_$low $=$ reshape$($decoded$\_$low, size$($lenna$\_$gray, $1),[])$;

$\%$ Plot original and received image at low SNR

figure;

subplot$(1,2,1)$; imshow$($lenna$\_$gray$)$; title$(\text{'}$Original Image'$)$;

subplot$(1,2,2)$; imshow$($decoded$\_$image$\_$low$)$; title$(\text{'}$Received Image $(0$ dB SNR$)\text{'})$;

$\%$ Transmit and receive at high SNR

received$\_$high $=$ awgn$($double$($lenna$\_$bits$),$ SNR$\_$high, 'measured'$)$;

$\%$ Demodulation

decoded$\_$high $=$ received$\_$high $<0$;

$\%$ Reshape decoded bits to original image size

decoded$\_$image$\_$high $=$ reshape$($decoded$\_$high, size$($lenna$\_$gray, $1),[])$;

$\%$ Plot original and received image at high SNR

figure;

subplot$(1,2,1)$; imshow$($lenna$\_$gray$)$; title$(\text{'}$Original Image'$)$;

subplot$(1,2,2)$; imshow$($decoded$\_$image$\_$high$)$; title$(\text{'}$Received Image $(4$ dB SNR$)\text{'})$;

$\%$ Linear error detection code

$\%$ Example: Hamming $(7,4)$ code

parityMatrix $=[1110100$; $1101010$; $1011001]$;

generatorMatrix $=[$eye$(4)$ parityMatrix'$]$;

$\%$ Encode the data

encoded$\_$data $=$ mod$($lenna$\_$bits $*$ generatorMatrix, $2)$;

$\%$ Add noise for linear error detection code

received$\_$data $=$ awgn$($double$($encoded$\_$data$),$ Eb$\_$No$\_$low, 'measured'$)$;

$\%$ Syndrome lookup table for error detection

syndrome$\_$table $=$ syndtable$($parityMatrix$)$;

$\%$ Decoding with error detection

decoded$\_$data $=$ zeros$($size$($encoded$\_$data$))$;

errors $=$ zeros$($size$($encoded$\_$data, $1),1)$;

for i $=1$:size$($encoded$\_$data, $1)$

syndrome $=$ mod$($received$\_$data$($i$,$ :) $*$ parityMatrix', $2)$;

if sum$($syndrome$)$ ~$=0\%$ Error detected

errors$($i$)=1$;

else

decoded$\_$data$($i$,$ :) $=$ received$\_$data$($i$,$ :$)$;

end

end

$\%$ Count number of retransmission requests at different SNRs

SNRs $=[0,2,4,6,8,10]$;

retransmissions $=$ zeros$($size$($SNRs$))$;

for i $=1$:length$($SNRs$)$

SNR $=10^($SNRs$($i$)/10)$;

received$\_$data $=$ awgn$($encoded$\_$data, SNR$,$ 'measured'$)$;

errors $=$ zeros$($size$($encoded$\_$data, $1),1)$;

for j $=1$:size$($encoded$\_$data, $1)$

syndrome $=$ mod$($received$\_$data$($j$,$ :) $*$ parityMatrix', $2)$;

if sum$($syndrome$)$ ~$=0\%$ Error detected

errors$($j$)=1$;

retransmissions$($i$)=$ retransmissions$($i$)+1$;

end

end

end

$\%$ Plot number of retransmissions against SNR values

figure;

plot$($SNRs$,$ retransmissions, $\text{'}-$o$\text{'})$;

xlabel$(\text{'}$SNR $($dB$)\text{'})$;

ylabel$(\text{'}$Number of Retransmissions'$)$;

title$(\text{'}$Number of Retransmissions vs SNR$\text{'})$;

$\%$ Error correction code

$\%$ Example: Reed$-$Solomon code

n $=255$;

k $=223$;

t $=16$;

rs$\_$encoder $=$ comm.RSEncoder$($n$,$ k$)$;

rs$\_$decoder $=$ comm.RSDecoder$($n$,$ k$)$;

$\%$ Encode data

encoded$\_$rs $=$ step$($rs$\_$encoder, double$($lenna$\_$bits$))$;

$\%$ Add noise for Reed$-$Solomon code

received$\_$rs$\_$low $=$ awgn$($double$($encoded$\_$rs$),$ Eb$\_$No$\_$low, 'measured'$)$;

received$\_$rs$\_$high $=$ awgn$($double$($encoded$\_$rs$),$ Eb$\_$No$\_$high, 'measured'$)$;

$\%$ Decode received data

decoded$\_$rs$\_$low $=$ step$($rs$\_$decoder, received$\_$rs$\_$low$)$;

decoded$\_$rs$\_$high $=$ step$($rs$\_$decoder, received$\_$rs$\_$high$)$;

$\%$ Reshape decoded bits to original image size

decoded$\_$image$\_$rs$\_$low $=$ reshape$($decoded$\_$rs$\_$low, size$($lenna$\_$gray$))$;

decoded$\_$image$\_$rs$\_$high $=$ reshape$($decoded$\_$rs$\_$high, size$($lenna$\_$gray$))$;

$\%$ Plot original and received images with error correction

figure;

subplot$(1,2,1)$; imshow$($decoded$\_$image$\_$low$)$; title$(\text{'}$Received Image $(0$ dB SNR$,$ No Error Correction$)\text{'})$;

subplot$(1,2,2)$; imshow$($decoded$\_$image$\_$rs$\_$low$)$; title$(\text{'}$Received Image $(0$ dB SNR$,$ Error Correction$)\text{'})$;

figure;

subplot$(1,2,1)$; imshow$($decoded$\_$image$\_$high$)$; title$(\text{'}$Received Image $(4$ dB SNR$,$ No Error Correction$)\text{'})$;

subplot$(1,2,2)$; imshow$($decoded$\_$image$\_$rs$\_$high$)$; title$(\text{'}$Received Image $(4$ dB SNR$,$ Error Correction$)\text{'})$;