How to detect the number of cars in an image? how to display their count?

Hi everyone. Iam very new to the matlab software. Iam trying to display the number of cars present in an image and to display their count. I tried it by using foreground detector. It is working for videos. but i want to detect cars in an image. If anyone knows it , please help me. Thank you

[Image Analyst]

If they're not moving then it would be very difficult. A car, or portion of a car, could look like almost anything.