Photomosaic Journal - Reverse Chronological

Step 7 - Replace 'pixels' with smaller images

Photomosaic Journal - Reverse Chronological

Step 6 - Average Color Images
I resized the 9x9 images in this blog so that they could actually be seen.

(214, 128, 42)




(128, 128, 42)

(214, 214, 128)

(128, 42, 42)

(214, 128, 128)

(128, 42, 128)

(214, 128, 214)

(42, 42, 128)

(42, 128, 214)

(42, 128, 128)

(42, 42, 42)

(128,128,128)

(214,214,214)

Photomosaic Journal - Reverse Chronological

Step 6 - Average Color
I created the following functions in Octave to compute the average color of my 13 smaller (9x9) images:
(1) Average Color Red Channel:
function[picR]=avgR(pic,maxR)
picR=round(255*sum(sum(pic(:,:,1)))/(maxR*size(pic,1)*size(pic,2));
end;
(2) Average Color Green Channel:
function[picG]=avgG(pic,maxG)
picG=round(255*sum(sum(pic(:,:,2)))/(maxG*size(pic,1)*size(pic,2));
end;
(3) Average Color Blue Channel:
function[picB]=avgB(pic,maxB)
picB=round(255*sum(sum(pic(:,:,3)))/(maxB*size(pic,1)*size(pic,2));
end;
where pic=imread("smallaveragecolorpic.png");
max(pic)
ans(:,:,1)=maxR
ans(:,:,2)=maxG
ans(:,:,3)=maxB.
To recall: avgR(pic,maxR); avgG(pic,maxG); avgB(pic,maxB).
Average Color = (avgR, avgG, avgB).

Step 5 - Shrink/Crop Pictures from Step 4
I combined code from Assignment #7 (shrink2 - nearest neighbor) and Assignment #8 (shrinkd - scale an image in x and y by different factors) to reduce the size of my 'replacement pictures' to 9x9 squares, since I enlarged my image by a factor of r=9 in Step 3. The code:
function[S]=shrink2(pic,f1,f2,newpic)
Mp=floor(size(pic,1)*f1);
Np=floor(size(pic,2)*f2);
for i=1:Mp;
for j=1:Np;
a=round(i/f1);
b=round(j/f2);
for k=1:3;
S(i,j,k)=pic(a,b,k);
endfor;
endfor;
endfor;
imwrite(newpic, double(S)(:,:,1)/255, double(S)(:,:,2)/255, double(S)(:,:,3)/255);
endfunction;
A=imread("averagecolorpic.png");
shrink2(A, 9/size(A,1), 9/size(A,2), "smallaveragecolorpic.png").

Once the images are reduced to the pixel size (9x9) in my enlarged image from Step 3, it is impossible to tell what the original image was - dissapointing. In other words, it did not really matter that I just created the desired colors using the six images below, rather than finding images that actually had a dominant color purple, for example.

Step 4 - Finding Pictures to Replace Pixels in Image

I plan to use the following six images to replace each of the 13 colors in my photomosaic. I will mimic the colors using GIMP, so that the average colors are one of the 13 possible colors. In GIMP, Color>Levels>Channel>RGB>Output level (enter the color values). Note: Some images did not require level adjusting to obtain accurate average colors. Above each image are the colors they will replace.

orange, beige, salmon:

maroon:

purple, light purple:

olive green:

blue, aqua, teal:

black, grey, light grey:


My enlarged, reduced color image has 13 colors, determined by examining the pixels in zoom mode, and cross-referencing this with the matrix values displayed in Octave. Color chips below created in GIMP by opening a 100x100 chip file and using the bucket fill tool. Tools->Paint tools->Bucket Fill->Change Foreground Color->entered corresponding RGB values.

(214, 128, 42)

(128,128,42)

(214,214,128)

(128, 42, 42)

(214,128,128)

(128,42,128)

(214,128,214)

(42, 42, 128)

(42,128,214)

(42,128,128)

(42, 42, 42)

(128,128,128)

(214,214,214)