Fig. 1. Block compressed sensing（BCS）architecture with a graphics processing unit（GPU）acceleration imaging system

Fig. 2. Inverse（a，c，e）and CS（b，d，f）reconstruction results with subsampling rate = 0.3，the image sizes are（a），（b）32 × 32 pixels，（c），（d）64 × 64 pixels，and（e），（f）128 × 128 pixels

Fig. 3. Unit of projection vectors derived from a compressive element block. A part of the coding pattern on the SLM is divided into four identical parallelly measuring blocks. One measurement entry，which corresponds to a measurement operation and an observed value，is reshaped into a vector according to the vertical orientation

Fig. 4. Blocki is the observed value vector of the i-th compressed block used to recover the i-th original image block，Mj indicates the j-th measurement corresponding to j-th coding pattern，Blocki and Mj exactly indicate the observed value of i-th compressive block and j-th measurement，here，n=N×NC×C and m≤C×C

Fig. 5. Peak signal-to-noise ratio（PSNR）and reconstruction time with different block sizes and different under-sampling rates

Fig. 6. Block-compressive reconstruction procedure with GPU acceleration

Fig. 7. Comparison of experimental results from different low-resolution images with different compression ratios^［12］，a-1）–a-9）shows the digital chart，b-1）–b-9）is the film，c-1–c-9）is the toy，a，b，c-1），a，b，c-4）and a，b，c-7）are the low-resolution sampling images with 64 × 64 pixels，high-resolution MBCS reconstruction results with 128 × 128 pixels and the traditional block CS results，respectively，further，a，b，c-2），a，b，c-5）and a，b，c-8）are the low-resolution sampling images with 32 × 32 pixels，high-resolution MBCS reconstruction results with 128 × 128 pixels and the traditional block CS results，respectively，also，a，b，c-3），a，b，c-6）and a，b，c-9）are the low-resolution sampling images with 16 × 16 pixels，high-resolution MBCS reconstruction results with 128 × 128 pixels and the traditional block CS results，respectively

Fig. 8. Reconstruction time for the 128 × 128 scene by the MBCS algorithm using CPU and with GPU acceleration for different block sizes

Fig. 9. Reconstruction time for the 256 × 256 scene by the MBCS algorithm using CPU and with GPU acceleration for different block sizes

Fig. 10. Reconstruction time for the 512 × 512 scene by the MBCS algorithm using CPU and with GPU acceleration for different block sizes