How to merge two image without losing intensity in opencv

I have two images in opencv: Image A and Image B.

Image A is output frame from camera.
Image B is alpha transparent image obtained by masking one image.
Before masking Image B it is warped with cvWarpPerspective()

• I tried cvAddWeighted() - It looses intensity when you give alpha and beta value
• I tried aishack - Even here you looses overall intensity of Output Image
• I tried silveiraneto.net - Not helpful in my case

Please help me out with something where I don't lose intensity in the output image after blending.

Thanks in advance

I finally got the answer.It consist of 5 steps....

Step - 1

cvGetPerspectiveTransform(q,pnt,warp_matrix); 
//where pnt is four point x and y cordinates and warp_matrix is a 3 x 3 matrix

Step - 2

cvWarpPerspective(dst2, neg_img, warp_matrix,CV_INTER_LINEAR)
//dst2 is overlay image ,neg_img is a blank image 

Step - 3

cvSmooth(neg_img,neg_img,CV_MEDIAN); //smoothing the image

Step - 4

cvThreshold(neg_img, cpy_img, 0, 255, CV_THRESH_BINARY_INV);
//cpy_img is a created image from image_n

Step - 5

cvAnd(cpy_img,image_n,cpy_img);// image_n is a input image
cvOr(neg_img,cpy_img,image_n);

Output - image_n (without loosing intensity of input image)