Fault tolerant adders are an important design paradigm to improve the robustness of the adder while at the same time improving the yield. The major downside of fault tolerant adders are the additional modules that are intrinsic to this design. On the other hand, approximate adders take the advantage of computing resilience and inherently improve the area, delay & power metrics. A combination of these two seemingly contradictory approaches are juxtaposed to put forth a design for robust fault tolerant approximate adders that mitigate the effects of redundancy and would help improve the yield. The fault tolerant schemes included are the Triple Modular Redundancy and Partial Triple Modular Redundancy. These are used in conjunction with the approximate Lower part-OR Adder (LOA). The designed fault tolerant approximate adder along with the fault intolerant precise and fault intolerant imprecise adder is used for image sharpening using the Gaussian filter. The results analyzed in the presence and absence of faults indicate that the visual quality of the image in the presence of a single stuck-at fault is almost as good as that obtained without a fault and maintains a PSNR of above 27 in case of fault tolerant approximate adder. There is a significant loss in the image quality if a fault occurs in a non-redundant precise or approximate adder. The deterioration in image quality is more significant if a stuck-at-one fault occurs, as the image becomes visually indecipherable.

容错加法器是一种重要的设计范例，可以提高加法器的鲁棒性，同时提高成品率。容错加法器的主要缺点是该设计固有的附加模块。另一方面，近似加法器利用计算弹性的优势，从本质上改善面积、延迟和功率指标。将这两种看似矛盾的方法结合在一起，提出了一种稳健的容错近似加法器的设计，可以减轻冗余的影响并有助于提高产量。包括的容错方案是三重模块冗余和部分三重模块冗余。它们与近似的下部或加法器 (LOA) 结合使用。设计的容错近似加法器以及容错精确加法器和容错不精确加法器用于使用高斯滤波器进行图像锐化。在存在和不存在故障的情况下分析的结果表明，存在单个固定故障时图像的视觉质量几乎与没有故障时获得的图像一样好，并且在容错情况下保持PSNR高于27近似加法器。如果非冗余精确或近似加​​法器发生故障，图像质量会显着下降。如果发生固定故障，图像质量的恶化会更加严重，因为图像在视觉上变得难以辨认。