The issues in person re-identification can be classified into two categories i.e. Inter camera and Intra camera issues. Inter-camera issues can cause problems in identifying people in a network of cameras. The different illumination conditions that exist at different camera views should be consider here. The cameras have differences in illumination, because they have different features even if the cameras are from the same manufacturer. Another important issue is the different poses of persons in different camera views. These problems decrease the detection rate .Some of the problems in person re-identification are due to varying light condition at different times of the day (Figure 3). In addition, low resolution cameras reduce the quality of frames. So, the methods depend on quality of frames decrease the detection rate. Another important issue is occlusions in camera frames create difficulty in image segmentation (Figure 4). This is called Intra-camera issues.