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## Pixar in a Box

### Course: Pixar in a Box>Unit 6

Lesson 2: Mathematics of depth of field

# Mathematics of pinhole cameras

In this video we'll find the intersection point of a light ray and our image plane.

## Want to join the conversation?

• at why is the slope y0/x0? • The definition of slope is the change in vertical direction divided by change in horizontal direction between two points. It's practically a number telling you how steep is the curve. Bigger the number, steeper the curve. Because we know the light ray from captured object(x0,y0) comes through the pinhole (0,0), the change in horizontal direction is x0 - 0 and on vertical y0-0. The slope of the ray of captured object is therefore x0/y0. And because the point (x1,y1) on the image plane is the same light ray, therefore it lies on the same line as the captured object (x0,y0), it has the same slope. So we know that y1/x1=y0/x0. We can solve this equation for y1=(y0/x0)*x1, as was done in the video. Hope this helps, you can explore this idea further in lessons on slope in Math:Algebra 1 section here on Khan Academy ( https://www.khanacademy.org/math/algebra/two-var-linear-equations/slope/v/introduction-to-slope ).
• what software are you gonna have to use or is it any to make 3d image • Is it just me, or do the circles of confusion look really pretty when blurred? • I didn't understand a single bit. • How is animation related to maths? • is it only me or do people get confused when math is involved • I am in third grade and I don't understand the math. • In the next set of problems, why is the image plane always 6 units away from the pinhole? Is it for simplicity?   