In this figure above, the people may appear sad, up close, but step back a few meters and look at the expressions again!
What are you seeing? They all smiling at you!
This phenomenon is called hybrid effect. A hybrid image is a picture that combines the low-spatial frequencies of one picture with the high spatial frequencies of another picture, producing an image with an interpretation that changes with viewing distance.
In this picture, high spatial frequencies correspond to faces with ‘sad’ expressions, while low spatial frequencies correspond to the same faces with ‘happy’ and ‘surprise’ emotions (the emotions are, from left to right: happy, surprise, happy and happy). Therefore, when you step away a few meters from the picture, you are switching from one interpretation to the other one, which hence leads to the expression change.
Now, looking at this picture.
Can you see a motorcycle? In this situation, color at high spatial frequencies is used to enhance the bicycle up-close. Therefore, the shape of the motorcycle is interpreted as shadows up-close.
Given the following picture, can you explain the principle by using hybrid image effect?
(Hint: Cat woman; the texture corresponding to the cat’s face disappears when the image is viewed from a few meters.)
