     int s_dst_row = threadIdx.y;
     int s_dst_col = threadIdx.x;
     int s_dst_width = blockDim.x;
-
-    int s_equ_row = threadIdx.y;
-    int s_equ_col = threadIdx.x;
-    int s_equ_width = blockDim.x;
 
     // load g_src & g_dst into shared memory
     load_s_src(g_src, g_row, g_col, g_width, g_height, s_src, s_src_row, s_src_col, s_src_width);


    uint8_t* s_src = &s_data[0];
    uint8_t* s_dst = &s_data[(blockDim.x + PAD_LEFT + PAD_RIGHT) * (blockDim.y + PAD_TOP + PAD_BOTTOM)];
    uint8_t* s_equ = &s_data[((blockDim.x + PAD_LEFT + PAD_RIGHT) * (blockDim.y + PAD_TOP + PAD_BOTTOM)) + (blockDim.x * blockDim.y)];

    int g_row = blockIdx.y * blockDim.y + threadIdx.y;
    int g_col = blockIdx.x * blockDim.x + threadIdx.x;


    s_dst[(s_dst_row) * s_dst_width + (s_dst_col)] = BINARY_WHITE + ((1 - thinning_cond_ok) * s_src[s_src_row * s_src_width + s_src_col]);

    uint8_t write_data;

    // write dst pixel value to g_dst
    write_data = s_dst[(s_dst_row) * s_dst_width + (s_dst_col)];
    global_mem_write(g_dst, g_row, g_col, g_width, g_height, write_data);

    // write pixel equality information to g_equ
    write_data = (s_src[(s_src_row) * s_src_width + (s_src_col)] == s_dst[(s_dst_row) * s_dst_width + (s_dst_col)]);
    global_mem_write(g_equ, g_row, g_col, g_width, g_height, write_data);
}

// Computes the number of white to black transitions around a pixel.
