基于C语言的DCT图像分割
有人能告诉我们如何将图像分割成8X8块吗 我可以读取图像,但不能将其分割为8x8子矩阵进行DCT基于C语言的DCT图像分割,c,image,divide,dct,C,Image,Divide,Dct,有人能告诉我们如何将图像分割成8X8块吗 我可以读取图像,但不能将其分割为8x8子矩阵进行DCT int main() { FILE *image_raw; unsigned char **matriz_image; int i, j; int rows=1080, colums=1920; matriz_image = (unsigned char **) malloc (rows*sizeof(unsigned char *)); //i
int main()
{
FILE *image_raw;
unsigned char **matriz_image;
int i, j;
int rows=1080, colums=1920;
matriz_image = (unsigned char **) malloc (rows*sizeof(unsigned char *));
//i create dinamic colums
for(i=0; i<rows; i++)
{
matriz_image[i] = (unsigned char *) malloc (colums*sizeof(unsigned char ));
}
//i open image raw
image_raw = fopen("imag.dat", "r+b");
//i copy values to matriz_image
for (i = 0; i < rows; ++i)
{
fread(matriz_image[i], sizeof(unsigned char ), colums, image_raw);
}
for(i=0; i<rows; i++)
{
for(j=0; j<colums; j++)
{
// printf("%i ",*(*(matriz_image+i)+j));
printf("%i ",matriz_image[i][j]);
}
printf("\n");
}
intmain()
{
文件*image\u raw;
无符号字符**矩阵图像;
int i,j;
整数行=1080,列=1920;
matriz_image=(无符号字符**)malloc(行*sizeof(无符号字符*);
//我创造了恐龙柱
对于(i=0;i你可以这样做:
void dct(unsigned char **m, int baserow, int basecol)
{
for (int row = baserow, endrow = baserow + 8; row < endrow; ++row)
for (int col = basecol, endcol = basecol + 8; col < endcol; ++col)
; // operate on m[row][col]
}
int do_dcts(unsigned char **m, int num_rows, int num_cols)
{
if (num_rows <= 0 || num_rows % 8 || num_cols <= 0 || num_cols % 8)
return -1;
for (int row = 0; row < num_rows; row += 8)
for (int col = 0; col < num_cols; col += 8)
dct(m, row, col);
return 0;
}
如果可以生成行和列常量或具有VLA,则可以执行以下操作:
unsigned char (*m)[colums] = (unsigned char (*)[colums]) matriz_image;
m[5][2] = 2; // double indexed access without extra pointers + allocs
类似地,您可以将指向矩阵的m类指针传递给函数,以便对其进行操作
如果无法将行和列作为编译时常量,并且没有VLA,则可以编写帮助器FCN为您执行指针算术:
inline unsigned char *get_row(unsigned char *m, int numcols, int row)
{
return &m[row * num_cols];
}
inline unsigned char *get_elem(unsigned char *m, int numcols, int row, int col)
{
return &m[row * num_cols + col];
}
...
*get_elem(m, colums, 5, 2) = 2; // double indexing not as nice but good memory usage
如果您确实需要快速执行这些操作,那么在读取图像时,您可以重新组织图像,将8x8字节块连续放置在内存中,以获得最佳缓存性能:
// organize m like m[rows * colums / 64][8][8]; so first index is an 8x8 block #
for (int k = 0; k < rows / 8; ++k) // read all rows in chunks of 8
for (int i = 0; i < 8; ++i) // read 8 rows
for (int j = 0; j < colums / 8; ++j) // read 1 row in 8 byte chunks
fread(&m[k * 8 * colums + i * 8 + j * 64], 1, 8, image_raw);
...
typedef unsigned char (*block_ptr)[8];
inline block_ptr get_block(unsigned char *m, int num_cols, int block_num)
{
return (block_ptr) &m[block_num * 64];
}
inline block_ptr get_block2(unsigned char *m, int num_cols, int row, int col)
{
if (row % 8 || col % 8)
return NULL;
return (block_ptr) &m[row * num_cols + col * 8];
}
...
for (int k = 0; k < rows * colums / 64; ++k)
{
block_ptr block = get_block(m, num_colums, k);
for (int i = 0; i < 8; ++i)
for (int j = 0; j < 8; ++j)
; // operate on block[i][j];
}
//像m[rows*colums/64][8][8]一样组织m;所以第一个索引是一个8x8块#
for(int k=0;k
您想根据输入创建N个新的、独立的8x8矩阵吗?还是只想在8x8块中处理现有矩阵?我假设没有重叠?非常感谢!您的建议和代码。我看到了我的错误,我会注意的。最后,我为我的英语感到抱歉。
// organize m like m[rows * colums / 64][8][8]; so first index is an 8x8 block #
for (int k = 0; k < rows / 8; ++k) // read all rows in chunks of 8
for (int i = 0; i < 8; ++i) // read 8 rows
for (int j = 0; j < colums / 8; ++j) // read 1 row in 8 byte chunks
fread(&m[k * 8 * colums + i * 8 + j * 64], 1, 8, image_raw);
...
typedef unsigned char (*block_ptr)[8];
inline block_ptr get_block(unsigned char *m, int num_cols, int block_num)
{
return (block_ptr) &m[block_num * 64];
}
inline block_ptr get_block2(unsigned char *m, int num_cols, int row, int col)
{
if (row % 8 || col % 8)
return NULL;
return (block_ptr) &m[row * num_cols + col * 8];
}
...
for (int k = 0; k < rows * colums / 64; ++k)
{
block_ptr block = get_block(m, num_colums, k);
for (int i = 0; i < 8; ++i)
for (int j = 0; j < 8; ++j)
; // operate on block[i][j];
}