*Article* **A New Algorithm for the On-Board Compression of Hyperspectral Images**

#### **Raúl Guerra** *∗***, Yubal Barrios, María Díaz, Lucana Santos, Sebastián López and Roberto Sarmiento**

Institute for Applied Microelectronics (IUMA), University of Las Palmas de Gran Canaria (ULPGC), 35001 Las Palmas de Gran Canaria, Las Palmas, Spain; ybarrios@iuma.ulpgc.es (Y.B.); mdmartin@iuma.ulpgc.es (M.D.); lsfalcon@iuma.ulpgc.es (L.S.); seblopez@iuma.ulpgc.es (S.L.); roberto@iuma.ulpgc.es (R.S.)

**\*** Correspondence: rguerra@iuma.ulpgc.es; Tel.: +34-928-451-220

Received: 1 February 2018; Accepted: 6 March 2018; Published: 9 March 2018

**Abstract:** Hyperspectral sensors are able to provide information that is useful for many different applications. However, the huge amounts of data collected by these sensors are not exempt of drawbacks, especially in remote sensing environments where the hyperspectral images are collected on-board satellites and need to be transferred to the earth's surface. In this situation, an efficient compression of the hyperspectral images is mandatory in order to save bandwidth and storage space. Lossless compression algorithms have been traditionally preferred, in order to preserve all the information present in the hyperspectral cube for scientific purposes, despite their limited compression ratio. Nevertheless, the increment in the data-rate of the new-generation sensors is making more critical the necessity of obtaining higher compression ratios, making it necessary to use lossy compression techniques. A new transform-based lossy compression algorithm, namely *Lossy Compression Algorithm for Hyperspectral Image Systems* (HyperLCA), is proposed in this manuscript. This compressor has been developed for achieving high compression ratios with a good compression performance at a reasonable computational burden. An extensive amount of experiments have been performed in order to evaluate the goodness of the proposed HyperLCA compressor using different calibrated and uncalibrated hyperspectral images from the AVIRIS and Hyperion sensors. The results provided by the proposed HyperLCA compressor have been evaluated and compared against those produced by the most relevant state-of-the-art compression solutions. The theoretical and experimental evidence indicates that the proposed algorithm represents an excellent option for lossy compressing hyperspectral images, especially for applications where the available computational resources are limited, such as on-board scenarios.

**Keywords:** hyperspectral compression; lossy compression; on-board compression; orthogonal projections; Gram–Schmidt orthogonalization; parallel processing
