Sementic segmentation data and model compile in Keras I have multi-label data for semantic segmentation. For semantic segmentation for one class I get a high accuracy but I can't do it for multi-class segmentation.

I have 6 class labels so my Y train matrix is equal [78,480,480,6] ('channel last'), where 78 - number of images 480,480 -image size, 6-number of masks and X train matrix [78, 480, 480, 1]

The last lines of my CNN model:

l = Conv2D(filters=64, kernel_size=(1,1), activation='relu')(l)
output_layer = Conv2D(filters=6, kernel_size=(1,1), activation='sigmoid')(l)

model = Model(input_layer, output_layer)
model.compile(optimizer=Adam(2e-4), loss='categorical_crossentropy', metrics=['accuracy'])


I don't know what I hove done wrong that my multi-label semantic segmentation model doesn't have proper results.

Image and masks:
Two things that stand out is that you are using sigmoid as activation which is used for binary classification (it just squash values between 0 and 1). The other is that your learning rate is 5x lower than the default value. 

Also because you are classifying images, I think the title is misleading; semantics is associated with "meaning" i.e. with language.