ChemPix is a model aimed at recognizing hand-drawn hydrocarbon (molecules with only carbon and hydrogen atoms, shown in structure formulas as mostly lines without letter notations) structures to their SMILES strings. They use a network architecture adapted from image captioning, with a CNN encoder and an LSTM with an attention mechanism and beam search as the decoder . They limited their dataset to rings with sizes less than eight carbons, and molecules with multiple conjoined rings were not considered. They use both synthetic and authentic hand-drawn images to train the model. They also used a "voting committee" consisting of multiple models to vote for the final answer. In their testing, the model can reach 76% top-1 accuracy and 86% top-3 accuracy.