I am not sure what cell are . I think they are pixels.
This maybe a long approach but this is what comes to my mind.
You will have to use OpenCV for this.
1.Transform image into HSV color space
2.Create masks for Red and Green
import cv2

image = cv2.imread('image_path')
image_copy = image.copy()
image_hsv = cv2.cvtColor(image_copy, cv2.COLOR_BGR2HSV)

green_lower = np.array([45,0,0])
green_upper = np.array([70,255,255])
mask_green = cv2.inRange(image_hsv, green_lower, green_upper)
green_cells = np.sum(mask_green)

red_lower = np.array([0,0,0])
red_upper = np.array([5,255,255])
mask_red = cv2.inRange(image_hsv, green_lower, green_upper)
red_cells = np.sum(mask_red)

Is this Okay ?