Abstract:
An image enhancing method using a mean-separate histogram equalization method is disclosed. An input image signal is divided into two sub-images in a picture unit according to a mean level of the input image signal. Then, cumulative density functions for each of the sub-images are calculated. Afterwards, the input sample is mapped into two gray levels, each of which belongs to a first range and a second range, by using first and second transform functions defined by use of the cumulative density functions, respectively. Finally, one of two mapped levels is selected depending on the magnitude of the input sample. As a result, the brightness of the given image can be preserved while the contrast is enhanced.
Abstract:
A bipolar plate for fuel cells includes a plurality of flow paths in which fuel flows. The flow paths include a first flow path formed by a plurality of flow channels and a second flow path formed by a plurality of islands. A direct liquid fuel cell stack comprises the bipolar plate.
Abstract:
A bipolar plate and a direct liquid feed fuel cell stack are provided. The bipolar plate includes a manifold that is coupled with the fuel/oxidant path holes and a plurality of flow channels that are coupled with the manifold. The flow channels are divided into a plurality of groups, where the flow channel of each group forms a serpentine flow path and a length of each flow channel is substantially the same.
Abstract:
A bipolar plate and a direct liquid feed fuel cell stack are provided. The bipolar plate includes a manifold that is coupled with the fuel/oxidant path holes and a plurality of flow channels that are coupled with the manifold. The flow channels are divided into a plurality of groups, where the flow channel of each group forms a serpentine flow path and a length of each flow channel is substantially the same.
Abstract:
A bipolar plate for fuel cells includes a plurality of flow paths in which fuel flows. The flow paths include a first flow path formed by a plurality of flow channels and a second flow path formed by a plurality of islands. A direct liquid fuel cell stack comprises the bipolar plate.
Abstract:
An image format converting method and apparatus are provided. The image format converter includes a pre-filter for pre-filtering the input image and for outputting a pre-filtered signal, and a format converter for bi-linear interpolating the pre-filtered signal, according to a predetermined aspect ratio, and for outputting a format converted signal. Therefore, the image format converter can have simple structure by adding the pre-filter, before the format converter using simple bi-linear interpolation, so that the image can be enlarged or reduced while remaining distinct and without aliasing.
Abstract:
A histogram-equalization method and circuit for enhancing an image signal represented by a predetermined number of gray levels is presented. The method calculates a cumulative density function and a mean level in a unit of a picture, and maps an input sample into a new gray level according to a transform function which is defined by use of the cumulative density function and the mean level. The method may also include a step of obtaining a compensated mean level by adding to the mean brightness level, so that the input sample is mapped into the compensated mean level according to the mean level. Thus, a brightness compensation may be carried out along with the contrast enhancement of the image.