Image enhancement is a field that is being used in various areas and disciplines. Advances in computers, microcontrollers and DSP boards have opened new horizons to digital image processing, and have opened many avenues to the design and implementation of new innovative techniques. This paper compares image enhancement via the modification of the probability density function of the gray levels with the new techniques that involves the use of knowledge-base (fuzzy expert) systems that are capable of mimicking the behavior of a human expert. A fuzzy expert system based software for image enhancement, called SmartPhotoLab â has been introduced for the above purpose.
IntroductionImage processing is a field that dates back to the 1920s, but the limitations due to the speed of the processing units and the available storage space have handicapped its progress and spread. Nowadays, the ever-growing advances in the computer technologies have reduced these limitations to a negligible level. Hence, the interest and the need for digital image processing have increased sharply. Today, image processing has applications in many fields and disciplines. Improvement of pictorial information for human interpretation and processing image information for autonomous machine perception were two main reasons behind the need for image processing [8]. Traditionally, all the image processing techniques have been based purely on mathematical approaches without any incorporation of human experience and knowledge that might have developed after years of working in the field. Recently, new techniques are being developed to mimic human reasoning, and to encode it into computer software programs that in some cases have proven superior results over the conventional techniques [2, 11].Processing of images for human perception is a rather complicated task. The determination of what is a ''good'' image is a subjective matter and differs from one viewer to another based on their taste and experience. On the other hand, image processing for autonomous machine perception is somewhat easier. Machines don't have taste, and the sole goal of image processing is to provide the information needed for the machine to perform a specific task. In either case, the determination of the right technique needs experimentation.This paper's main objective is to present a fuzzy expert system which can enhance digital and analog images. This expert system represents the core of an associated software environment known as SmartPhotoLab â , which can be used to enhance images from all popular formats. The expert system in SmartPhotoLab â is also used in hardware set up to enhance standard 35-mm film analog images.In the first part of this paper concentrates on providing a brief understanding of few of the key elements and methodologies of image processing. The second part will be dedicated to examining one of the conventional techniques used in image enhancement for human interpretation as well as the new intelligent techniques that are based on expert systems. Two example...