✓
            
            Distance is at least 2 m AND the angle to the nearest side of the monitoring area is at least 20° 
            All objects on the near side are in field of view and are recognizable.
         
        
            
                ±
            
            Distance is 1 to 2 meters OR the angle to the nearest side of the monitoring area is 10° to 20°
            You may miss some objects on the near side.
         
        
            
                ×
            
            Distance is less than 1 m OR the angle to the nearest side of the monitoring area is less than 10°
            You will miss most objects on the near side..