MINC/教程/程式設計05
上一個教程遍歷了體積中的每個體素，對其加了1，並將輸出寫回同一個體積。在這裡我們將改進該示例：輸出將寫入一個新的體積，我們將使用超立方體進行資料處理。
超立方體是 minc 中的核心概念。它允許您從體積中提取任意（但連續）的資料塊，對其進行操作，然後將其寫回體積。這比單獨獲取每個體素快得多；但是，它需要更多的記憶體。
因此，繼續示例：此程式碼獲取一個體積，建立一個副本，該副本在所有方面都相同，只是每個體素都加了 1。新體積也將始終使用全域性縮放，無論輸入是否具有切片縮放。
#include <minc2.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
int main(int argc, char **argv) {
mihandle_t minc_volume, new_volume;
midimhandle_t dimensions[3], *dimensions_new;
double min, max;
int result, i;
unsigned long start[3], count[3];
unsigned int sizes[3];
double *slab;
if (argc != 3) {
fprintf(stderr, "Usage: input.mnc output.mnc\n");
}
/* open the volume - first command line argument */
result = miopen_volume(argv[1], MI2_OPEN_READ, &minc_volume);
/* check for error on opening */
if (result != MI_NOERROR) {
fprintf(stderr, "Error opening input file: %d.\n", result);
return(1);
}
/* get the dimension sizes */
miget_volume_dimensions(minc_volume, MI_DIMCLASS_SPATIAL,
MI_DIMATTR_ALL, MI_DIMORDER_FILE,
3, dimensions);
miget_dimension_sizes(dimensions, 3, sizes);
printf("Volume sizes: %u %u %u\n", sizes[0], sizes[1], sizes[2]);
到目前為止，一切都很好 - 這些程式碼對你來說應該都不陌生。請注意為新體積和新維度建立了兩個新變數。
/* allocate new dimensions */
dimensions_new = malloc(sizeof(midimhandle_t) * 3);
/* copy the dimensions */
for(i=0; i < 3; i++) {
micopy_dimension(dimensions[i], &dimensions_new[i]);
}
在這裡，我們為新體積的維度分配記憶體，並從舊體積複製維度定義。
/* allocate memory for the hyperslab - make it size of entire volume */
slab = malloc(sizeof(double) * sizes[0] * sizes[1] * sizes[2]);
start[0] = start[1] = start[2] = 0.0;
if (miget_real_value_hyperslab(minc_volume, MI_TYPE_DOUBLE,
start, count, slab) != MI_NOERROR) {
fprintf(stderr, "Error getting hyperslab\n");
return(1);
}
為超立方體分配了記憶體，並獲得了超立方體 - 在這種情況下，超立方體是整個體積。關鍵函式是miget_real_value_hyperslab，它接受五個引數：minc 體積控制代碼，您想要資料所在的型別，開始的陣列（在本例中全為零），計數的陣列（體積大小）和寫入資料的地址。
/* set min and max to the first voxel plus 1
* (since we add one to everything anyway) */
min = slab[0]+1;
max = slab[0]+1;
/* loop over all voxels */
for (i=0; i < sizes[0] * sizes[1] * sizes[2]; i++) {
/* increment voxel by 1 */
slab[i] += 1;
/* check if min or max should be changed */
if (slab[i] < min) {
min = slab[i];
}
else if (slab[i] > max) {
max = slab[i];
}
}
現在我們迴圈遍歷超立方體中的每個體素（注意它是如何作為一維陣列處理的），確保保留修改後的影像最小值和最大值。
/* create the new volume */
if (micreate_volume(argv[2], 3, dimensions_new, MI_TYPE_UBYTE,
MI_CLASS_REAL, NULL, &new_volume) != MI_NOERROR) {
fprintf(stderr, "Error creating new volume\n");
return(1);
}
然後我們使用micreate_volume建立實際的體積。它接受七個引數：檔名，維度數，實際維度的陣列（透過上面的複製操作建立），資料型別（此處設定為無符號位元組），資料類，特殊體積屬性（此處設定為 NULL），以及體積控制代碼的地址。
/* create the data for the new volume */
if (micreate_volume_image(new_volume) != MI_NOERROR) {
fprintf(stderr, "Error creating volume data\n");
return(1);
}
現在，我們使用micreate_volume_image確保資料在 minc 體積控制代碼中建立。
/* set valid and real range */
miset_volume_valid_range(new_volume, 255, 0);
miset_volume_range(new_volume, max, min);
/* write the modified hyperslab to the file */
if (miset_real_value_hyperslab(new_volume, MI_TYPE_DOUBLE,
start, count, slab) != MI_NOERROR) {
fprintf(stderr, "Error setting hyperslab\n");
return(1);
}
然後我們設定有效範圍 - 從 0 到 255，因為這是無符號位元組資料 - 以及體積範圍，這是透過在迴圈遍歷體素時跟蹤最小值和最大值確定的。超立方體使用miset_real_value_hyperslab放回體積，它接受與miget_real_value_hyperslab完全相同的引數。
/* closes the volume and makes sure all data is written to file */
miclose_volume(minc_volume);
miclose_volume(new_volume);
/* free memory */
free(dimensions_new);
free(slab);
return(0);
}
最後，我們關閉體積，釋放已分配的記憶體並退出。
#include <minc2.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
int main(int argc, char **argv) {
mihandle_t minc_volume, new_volume;
midimhandle_t dimensions[3], *dimensions_new;
double min, max;
int result, i;
unsigned long start[3], count[3];
unsigned int sizes[3];
double *slab;
if (argc != 3) {
fprintf(stderr, "Usage: input.mnc output.mnc\n");
}
/* open the volume - first command line argument */
result = miopen_volume(argv[1], MI2_OPEN_READ, &minc_volume);
/* check for error on opening */
if (result != MI_NOERROR) {
fprintf(stderr, "Error opening input file: %d.\n", result);
return(1);
}
/* get the dimension sizes */
miget_volume_dimensions(minc_volume, MI_DIMCLASS_SPATIAL,
MI_DIMATTR_ALL, MI_DIMORDER_FILE,
3, dimensions);
miget_dimension_sizes(dimensions, 3, sizes);
printf("Volume sizes: %u %u %u\n", sizes[0], sizes[1], sizes[2]);
/* allocate new dimensions */
dimensions_new = malloc(sizeof(midimhandle_t) * 3);
/* copy the dimensions */
for(i=0; i < 3; i++) {
micopy_dimension(dimensions[i], &dimensions_new[i]);
}
start[0] = start[1] = start[2] = 0;
for (i=0; i < 3; i++) {
count[i] = (unsigned long) sizes[i];
}
/* allocate memory for the hyperslab - make it size of entire volume */
slab = malloc(sizeof(double) * sizes[0] * sizes[1] * sizes[2]);
if (miget_real_value_hyperslab(minc_volume, MI_TYPE_DOUBLE,
start, count, slab) != MI_NOERROR) {
fprintf(stderr, "Error getting hyperslab\n");
return(1);
}
/* set min and max to the first voxel plus 1
* (since we add one to everything anyway) */
min = slab[i]+1;
max = slab[i]+1;
/* loop over all voxels */
for (i=0; i < sizes[0] * sizes[1] * sizes[2]; i++) {
/* increment voxel by 1 */
slab[i] += 1;
/* check if min or max should be changed */
if (slab[i] < min) {
min = slab[i];
}
else if (slab[i] > max) {
max = slab[i];
}
}
/* create the new volume */
if (micreate_volume(argv[2], 3, dimensions_new, MI_TYPE_UBYTE,
MI_CLASS_REAL, NULL, &new_volume) != MI_NOERROR) {
fprintf(stderr, "Error creating new volume\n");
return(1);
}
/* create the data for the new volume */
if (micreate_volume_image(new_volume) != MI_NOERROR) {
fprintf(stderr, "Error creating volume data\n");
return(1);
}
/* set valid and real range */
miset_volume_valid_range(new_volume, 255, 0);
miset_volume_range(new_volume, max, min);
/* write the modified hyperslab to the file */
if (miset_real_value_hyperslab(new_volume, MI_TYPE_DOUBLE,
start, count, slab) != MI_NOERROR) {
fprintf(stderr, "Error setting hyperslab\n");
return(1);
}
/* closes the volume and makes sure all data is written to file */
miclose_volume(minc_volume);
miclose_volume(new_volume);
/* free memory */
free(dimensions_new);
free(slab);
return(0);
}