Overlay projective texturing

Hello I am a biginner in Opengl

I’ve been trying to implement to overlay transparent textures on the same quad plane .

Here is what I do.

Firstly, I locate cameras by using their intrinsic, and extrinsic calibration data.

Secondly, I put the quads in front of my view, and project images from cameras

Thirdly, I use glblendfunc to mix projected textures.

I’ve tried making same number of quads as the number of textures and use glblendfunc(gl_src_alpha gl_one_minus_src_alpha) to blend all of those textures

but it seems like I can’t get the result which I want (Only overlayed part is shown alpha = 1)

This is what I think to implement

for img in ref_imgs
for pixel in imgs.pixel
if pixel.alpha !=0
quad.pixel.color += img.pixel.color
quad.pixel.color/=number of ref_imgs

//only if alpha is 0 , calculate the average of colors of pixels

Any suggestions or help so that I can handle this problem?