input images (all with 1-, 3- or 4-channels).
Optional
scaleFactor: numberOptional
size: Sizespatial size for output image
Optional
mean: Vec3scalar with mean values which are subtracted from channels. Values are intended to be in (mean-R, mean-G, mean-B) order if image has BGR ordering and swapRB is true.
Optional
swapRB: booleanflag which indicates that swap first and last channels in 3-channel image is necessary.
Optional
crop: booleanflag which indicates whether image will be cropped after resize or not
Optional
ddepth: numberDepth of output blob. Choose CV_32F or CV_8U.
4-dimensional Mat with NCHW dimensions order.
Creates 4-dimensional blob from series of images. Optionally resizes and crops images from center, subtract mean values, scales values by scalefactor, swap Blue and Red channels.
if crop is true, input image is resized so one side after resize is equal to corresponding dimension in size and another one is equal or larger. Then, crop from the center is performed. If crop is false, direct resize without cropping and preserving aspect ratio is performed.
https://docs.opencv.org/4.x/d6/d0f/group__dnn.html#ga0b7b7c3c530b747ef738178835e1e70f