Pixel-based collision detection with sphere

You can get the contact point using this formula:

Pc = C - n[(C-P)dot(n)]

Pc: contact point
C: ball's center
n: the unit vector normal to the table and pointing upward
P: any point on the surface of the table

The quantity [(C-P)dot(n)] is the closest distance from the ball's center to the table. If this distance is greater than the ball's radius, there is no collision..

If you want an analytic solution, neglecting friction:

y(x) = y0 + vy*(x-x0)/vx - 0.5 * g * [(x-x0)/vx]^2

vx,vy : initial speed in x and y directions
y0,x0 : initial position
g : acceleration due to gravity

impact is when y(x) = h + r
where h is the height of the table and r the radius of the ball