Photomosaics - Image Variety Sample

The more images you can supply, the better the chances are that the target image can be matched more accurately. A minimum of 250 images is recommended, assuming there is quite a lot of variety within that set. Obviously a set of 1,000 images will be even better. If the images are somewhat similar, such as pictures of the same person, then an even larger set would be helpful as the variety of details will be lower.

In the following example, we will use a cropped view of the face of the girl in the 1665 painting Girl with a Pearl Earring, by the Dutch painter Jan Vermeer (1632-1675).

We start out by using only 5 original images, creating a database of a mere 15 images. You can see that the basic shape of the target image was matched and you can see that the target image is being approximated, but not very well.

Now we use 25 original images, for a database of 75 images. Detail is clearly improved, but the greatest improvement is seen in the color rendition, because the 25 images have greater color variation than the 5 images picked in the previous example.

Now we use 100 original images, for a database of 300 images. Additional improvement is seen, although it is more subtle. There is a patch of blue images picked in the previous sample using 25 images that is not present here, because the additional images contain more images that better approximate the skin tone.

Finally we use a full 500 original images, for a database of 1,500 images. This results in such a large number of images that more subtle shading is clearly visible, resulting in much better rendition of the target image. Look particularly at the smoothness in the skin and the more gradual shading of the headdress. The additional images also allow better rendition of the shape of the nose and lips, as well as the eyes and of course the critical pearl earring which is the whole point of the painting. If you squint you can make out tiny details such as the teeth peeking out between the slightly open lips, or the reflections in the eyes.