image_utils_ocl.py 文件源码

def local_entropy(ocl_ctx, img, window_radius, num_bins=8):
  """ compute local entropy using a sliding window """
  mf = cl.mem_flags
  cl_queue = cl.CommandQueue(ocl_ctx)
  img_np = np.array(img).astype(np.float32)
  img_buf = cl.Buffer(ocl_ctx, mf.READ_ONLY | mf.COPY_HOST_PTR, hostbuf=img_np)
  min_val = np.nanmin(img)
  max_val = np.nanmax(img)
  entropy = np.zeros_like(img,dtype=np.float32)
  dest_buf = cl.Buffer(ocl_ctx, mf.WRITE_ONLY, entropy.nbytes)
  cl_dir = os.path.dirname(__file__)
  cl_filename = cl_dir + '/cl/local_entropy.cl'
  with open(cl_filename, 'r') as fd:
    clstr = fd.read()
  prg = cl.Program(ocl_ctx, clstr).build()
  prg.local_entropy(cl_queue, entropy.shape, None,
                    img_buf, dest_buf,
                    np.int32(img.shape[1]), np.int32(img.shape[0]),
                    np.int32(window_radius), np.int32(num_bins),
                    np.float32(min_val), np.float32(max_val))

  cl.enqueue_copy(cl_queue, entropy, dest_buf)
  cl_queue.finish()

  return entropy