for file in os.listdir(trainingCharsetsDir + '/' + str(trainingSet)):
            charImg = cv.imread(
                trainingCharsetsDir + '/' + str(trainingSet) + '/' + file,
                cv.IMREAD_GRAYSCALE)
            normalize_array(charImg, 255, 0)

            # feedforward
            #--------------------------- 1st ---------------------------------
            inputLayerOutput = np.zeros(inputNeuronCount)
            inputLayerOutput[0] = bias1
            index = 1
            for item in charImg.flat:
                inputLayerOutput[index] = item
                index += 1

            layer1.input_signals = inputLayerOutput
            #--------------------------- 1st ---------------------------------

            #--------------------------- 2nd ---------------------------------
            layer1Output[0] = bias1
            index = 1
            for item in layer1.calculateOutputSignals():
                layer1Output[index] = item
                index += 1

            layer2.input_signals = layer1Output
            #--------------------------- 2nd ---------------------------------

            #------------------------- output --------------------------------
            layer2Output = layer2.calculateOutputSignals()
            #------------------------- output --------------------------------