How can I render an image with sharp and uniform color edges? I'm modeling a simple scene of black board (diffuse material) with red, green, yellow, and white squares (emission material) on it. 

The following is a crop of the rendered result.



All the squares I modeled have same size, however after rendering, the last square shown in the image is smaller than the rest. One square has a lighter edge (marked #1). 
I think this has something to do with anti-aliasing used in Blender cycles. The following is my rendering setting. 


I want all the squares to have the same size in final rendered image and uniform color even in edges (like the first 4 squares shown in the image above).  I was searching for a solution but couldn't find one. Can anyone suggest a solution for me? Thank you all in advance.
It has been a while, but IIRC the method to get pixel precision is via our output resolution and the scale of your objects.

For example, if your resolution is 1920x1080, you can create a pixel precise plane if you set the plane's dimensions to 1.920 and 1.080. Note that if you use larger scales, your images will suffer from cubic interpolation that will degrade any textures you place on them.

An orthographic camera should flatten the perspectival transform to be pixel perfect.