How to create and save the contourf image to pixel by pixel and the grey-level from 0-192

Hello, I am a beginner at Matlab. I would like to create contourf plot. The plot size is pixel by pixel, and the grey level from 0-192. The code as below,

r_M = [4.76083603812144 4.59732757325507 3.84078375990161 2.83522761891933 2.03979313208838 1.61429885435575 1.58483400872700 2.07651813385661 2.55722735199852 2.72392206632444 2.93752535716962 3.36165244504211 4.22402540734126

5.09135259357986 5.14098053905767 3.84735386504628 2.90588398495713 2.16965294670956 1.75800774970059 1.60816653904618 2.09786569025139 2.35707830751551 2.72724672816220 2.92950291189290 3.14937669175105 3.55234768789906

5.32921037462212 5.19557229019368 3.64288236574948 2.59423164048293 2.05593607322099 1.62600765104696 1.39272324365209 1.94639828163833 2.39067573713014 2.76682320807590 3.08555090153314 3.34114325174325 3.48149717381015

5.32220300581207 4.77648710556025 3.33861857929257 2.30001087201542 1.72605713634148 1.30014731381246 1.27834395153522 1.44070837985961 2.28502229697568 3.05248804492776 3.46260438310124 3.48706102771820 3.51030149578596

4.77942253753882 4.46906792789553 3.34795711428994 2.16465765653945 1.46191531056537 0.977488872989844 0.753852737116531 1.27219788209603 2.08210681473467 3.03256963334665 3.64937747540501 3.65792537276952 3.74565551110235

4.35299275691490 4.09126935363725 3.17753495331855 2.00277281204170 1.24584659356560 0.971882708826663 0.359926751275065 0.750288700163987 1.65295259354634 2.78437256856132 3.88785048392134 4.12080325961920 3.91064049184246

3.93553132820880 3.59037099875034 3.00742566363658 2.22310301463755 1.40329829105446 0.641720673990197 0 0.353817971764671 1.25050401867387 2.52705374697445 3.90206241164242 4.23322992408431 4.07966270942597

3.81297584814867 3.50496940639607 3.07287706439689 2.35995332346616 1.86413217218313 0.936682281145216 0.260044105867860 0.421385784308465 1.16132826321159 2.46123588438794 4.02775557593691 4.61512984501341 4.56460461007416

3.68529588244402 3.45724972352478 3.08758001482871 2.71853149527819 2.01589401870171 1.20354143807865 0.587935492605682 0.670452733954317 1.32097352990551 2.73396811354949 3.39007402374409 5.12073156989824 5.19172525646325

3.57346310861397 3.30138171990411 2.94197749316414 2.76413214744990 2.20208725235252 1.60173122994903 1.11863252129357 1.05812096331277 1.41869726718747 2.25935488759645 3.69156460669313 5.55839137321558 5.66354993152361

3.65235145805927 3.17599433524990 2.86927834788569 2.62713472885208 2.18853259171050 1.85215737698314 1.37566911617467 1.43058696816551 1.71420712042859 2.17640898749974 3.77395656277310 5.85285012374981 6.21778688895472

3.88096688920101 3.25616920202222 2.94078301742807 2.49926413516375 2.08893540306161 1.76158511353697 1.58802372581860 1.49797801272054 1.65308574844975 2.50599597127705 3.97368783274096 6.05695466074494 6.57069113812358

4.49676159104381 3.28110982226297 2.97248320745266 2.51555310405689 2.18534801655490 1.67462553900224 1.32835750776993 1.30126235023730 1.60772857482591 2.41658242378975 3.88480146299220 5.64471842496219 6.78487213551137];

Max = max (r_M (:));

Min = min(r_M(:));

I = mat2gray(r_M,[Min Max]);

figure(104)

contourf(X,Y,b,256,'LineColor','none')

colormap(flipud(gray(256)));

set(gca,'xtick',[])

set(gca,'ytick',[])

Thanks a lot.

[KALYAN ACHARJYA]

X and Y??

[Tina Hsiao]

X=[

-150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150

-150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150

-150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150

-150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150

-150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150

-150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150

-150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150

-150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150

-150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150

-150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150

-150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150

-150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150

-150 -125 -100 -75 -50 -25 0 25 50 75 100 125 150]

Y =[

-150 -150 -150 -150 -150 -150 -150 -150 -150 -150 -150 -150 -150

-125 -125 -125 -125 -125 -125 -125 -125 -125 -125 -125 -125 -125

-100 -100 -100 -100 -100 -100 -100 -100 -100 -100 -100 -100 -100

-75 -75 -75 -75 -75 -75 -75 -75 -75 -75 -75 -75 -75

-50 -50 -50 -50 -50 -50 -50 -50 -50 -50 -50 -50 -50

-25 -25 -25 -25 -25 -25 -25 -25 -25 -25 -25 -25 -25

0 0 0 0 0 0 0 0 0 0 0 0 0

25 25 25 25 25 25 25 25 25 25 25 25 25

50 50 50 50 50 50 50 50 50 50 50 50 50

75 75 75 75 75 75 75 75 75 75 75 75 75

100 100 100 100 100 100 100 100 100 100 100 100 100

125 125 125 125 125 125 125 125 125 125 125 125 125

150 150 150 150 150 150 150 150 150 150 150 150 150]

[Tina Hsiao]

Thanks a lot