A question about implementation of code in Avalon Steaming Interface

Hi, I am doing a project which uses HLS method to do Gaussian-Sobel edge detection. What in the screenshot is part of my HLS C++ code and warnings and errors in command prompt.

However, when I was trying to generate executable file, the command prompt suggests the two objects, input_pixel and output_pixel in the component declaration, are not declared. I don't now why. I don't think my this part of code has any difference with the sample code provided in HLS official tutorials. Can anyone help me? Thanks.