Traditionally, dietary fiber was defined as the portions of plant foods that were resistant to digestion by human digestive enzyme which includes cellulose, noncellulosic polysaccharides such as hemicellulose, gums, mucilages and a non-carbohydrate component lignin.Various studies have revealed an inverse relationship between dietary fiber intake and the risk of developing chronic diseases such as cardiovascular disease, cancer, diabetes and obesity. However the dietary fiber intake is lower than the recommended (30g/day). Therefore, the development of foods with high fiber content should be desirable. In the present study, the response surface methodology was used to determine the optimum fermentation condition and quantity of dietary fiber that gave the best quality, shelf life, overall acceptability and image properties for Barbari flat bread. Time, yeast and fibers percent tested at five, five and four levels respectively. Times were 42, 60, 85, 110 and 127 mins, yeast percent were 0.66, 1, 1.5, 2 and 2.34% (flour weight basis) and fibers were 0, 2, 6, 10 percent. As well the effect of two types of commercial dietary fibers (apple fiber and potato fiber) on dough rheology and bread quality was studied. Evaluation of dough properties was carried out by farinogeraph, Dough Expansion during Fermentation by image analysis, uniaxial extension and stress relaxation by using a Texture Analyzer machin. Results showed that water absorption, development time and tensile resistance increase, whereas extension, stability (with the exception of potato fiber at 6% substitution) and dough volume decrease by replacing wheat flour with dietary fibers. These results indicated that the dietary fiber alter the characteristics and handling properties of bread doughs. So the changes in processing condition is necessary. bread characteristics were studied by using texture profile analysis (TPA) and image analysis. Fiber-containing formulations affected bread specific volume and crumb firmness, crumb microstructure, color and these characteristics (with the exception of color crumb) were also dependent on both the fermentation time and yeast percentage. The inclusion of Dietary fibers in the bread formulation induced a reduction in the specific volume of the bread and an increase of firmness. However the lowest bread firmness magnitudes were observed in the Intermediate level of dietary fiber during storage period (24 and 48 hr). breads with better specific volume and softness values were achieved with increase of fermentation time and yeast percent. The results of image analysis indicated that fibers and fermentation condition affected the number of gas cells, porosity and fractional dimension. Apple Fiber and potato Fiber decrease the porosity and average cells size of enriched bread. So These breads had a more compact structure. Color measurement of the bread showed that the bread became darker with increasing level of either of dietary fiber and apple fiber enriched bread had a darker crumb than potato fiber enriched bread. Result of sensory test showed that, overall acceptability of bread with fiber, lower than the bread without it. The optimum condition was found to be fermentation time of 110 min, yeast percent %1.88 and apple fiber %5.11 also was found to be fermentation time of 110 min, yeast percent of %1.6 and potato fiber %7.33 as desirability function method was applied. The whole study indicates that these tow fibers can be used as additives in breadmaking in order to enrich the diet. Key Words: Dietary fiber, Functional bread, Image processing, Rheology of dough