In today's digital world, photos, videos and texts multiply at a breakneck pace. Searching for an image using a textual description, or vice versa, becomes a real puzzle for computers. Hashing steps in, turning complex data into short bit strings, called hash codes, easy to compare. The new RSDDH (Robust Supervised Deep Discrete Hashing) method offers an all‑in‑one approach: a convolutional neural network processes images, while a multilayer perceptron handles text, creating modality‑specific representations. The breakthrough lies in selecting non‑redundant features, discarding superfluous information and producing more distinctive codes. Moreover, RSDDH employs a discrete hashing scheme (SVDDH) that respects the binary nature of the codes without relaxations. To bridge the two worlds, the model preserves both inter‑modal and intra‑modal consistency. Tests on four benchmark datasets show RSDDH far outperforms previous methods, delivering faster and more accurate searches in massive multimedia collections.
RSDDH relies on a hybrid architecture that combines a CNN for visual feature extraction and an MLP for textual features. Non‑redundant feature selection is implemented via an L1 penalty on the importance vector, promoting sparsity and reducing dimensional correlation. The SVDDH core solves the binary optimization problem using a quadratic programming algorithm with discrete constraints, avoiding the usual continuous relaxation that can introduce quantization errors. To ensure inter‑modal consistency, the model minimizes Hamming distance between matching pairs (image‑text) with a contrastive loss, while intra‑modal consistency is maintained through a supervised classification loss on each modality. Training proceeds end‑to‑end with back‑propagation, simultaneously updating CNN weights, MLP parameters, and feature‑selection coefficients. Experiments report an average 12% MAP (Mean Average Precision) improvement over state‑of‑the‑art methods, confirming the benefit of redundancy reduction and discrete hash handling.
