In aerospace industry, the inspection is one of crucial process with the intention to produce a good quality product and avoid the crash of an aircraft. Improvement image processing and signal processing in line assist a lot in inspection process especially in non destructive evaluation (NDE). Both method need to clarify the accuracy of void detection. NDE plays an important role in the continued safe operation of physical asset mainly when image scanner and ultrasonic transducer indicate the presence of material discontinuities without doing harm to the component. In this report, we perform a digital image processing and signal processing techniques to extract information in the aerospace manufacturing composite panel mainly for the void detection and percentage. Important result and analysis of both method are also been discussed.