max_x = intimgshape0-heightstride+1

This line of code calculates the maximum value of x for a given image, height, and stride.

• img.shape[0] returns the height of the image.
• height is the height of the sliding window used for object detection.
• stride is the number of pixels to move the sliding window at each step.

The formula calculates how many times the sliding window can be moved vertically (along the height axis) within the image by dividing the difference between the image height and the window height by the stride and adding one. This gives the maximum value of x, which represents the number of times the sliding window can be moved vertically within the image.