We developed the automatically controlled X-rays compensating filter system (Automatic Filter System) to prevent the halation area that catheter's operation of the doctor in the angiography is obstructed. The algorithm which we have developed consists of the following five steps. 'Capture:' We take in a fluoroscopic image. 'Correction:' We correct the amount of decline by the X-rays compensating filter (filter) if the filter is already inserted. 'Detection:' We detect the halation area. 'Calculation:' We calculate an insertion position and rotate angle. 'Control:' We control the filter. We were able to get the following effects by the development of the Automatic Filter System. First, it was possible that the fluoroscopic image was displayed without losing contrast. Second, we were able to establish the most suitable X-rays conditions, such as tube voltage and tube current, for the region of interest (ROI), for example catheter and cardiovascular. And third, as the most important effect, we were able to decrease the exposure dose during the fluoroscopic procedure. Moreover, to confirm the validity of the Automatic Filter System, we applied this system to the angiography. As a result, we made sure that the operator could conduct the fluoroscopic procedure without manually control.