A method to be implemented by a computer system includes: transforming each of training images into a respective transformed training image; calculating a classification loss value based on detection results that are acquired from parking status prediction results obtained by performing feature extraction on the transformed training images; and adjusting candidate spatial transforming parameters, candidate feature extraction parameters and candidate logistic regression parameters when it is determined that a combination of the aforementioned parameters is not optimal based on the classification loss value, followed by repeating above-mentioned steps using the adjusted parameters.