typedef struct image_header 
   {
   char image_label[64];   /* image label  */
   unsigned char revision_num;      /* revision # for the header */
   unsigned char orient;            /* 0 = top to bottom and left to right
                                       1 = top to bottom and right to left
                                       2 = bottom to top and left to right
                                       3 = bottom to top and right to left */
   unsigned char file_flag;         /* 1 = Associated files exist, 
                                       0 = no files */
   unsigned char compress;          /* 0 = not  compressed */
                                    /* > 0 is the compression algo. code */
   unsigned short bits_gray;        /* Number of actual bits used */
   unsigned short bits_pixel;       /* Number of bits per pixel   */
   unsigned short row;              /* Row size   */
   unsigned short colm;             /* Column size */
   unsigned short max_value;        /* Max pixel value in the image */
   unsigned short min_value;        /* Min pixel value in the image */
   int  xpix_size;                  /* X direction pixel size in microns */
   int  ypix_size;                  /* Y direction Pixel size in microns */
   int  zpix_size;                  /* Slice thickness in microns  */
   int  sequence_value;             /* application dependent parameter
                                       (e.g. time,position ... etc. */
/* above defined for revision #s >= 0 */
   unsigned int   pixel_data;       /* 0 = integer data                 */
                                    /* 1 = real floating point data     */
                                    /* 2 = complex floating point data  */
   double  d_max_value;             /* Max pixel value in the image */
   double  d_min_value;             /* Min pixel value in the image */
/* above defined for revision #s >= 1 */
   unsigned char  byte_order;       /* 0 = low byte first  */
                                    /* 1 = high byte first */
   unsigned char  int_format;       /* 0 = unsigned           */
                                    /* 1 = signed (high bit)  */
   unsigned char  fp_format;        /* 0 = IEEE standard        */
                                    /* 1 = DEC VAX format       */
                                    /* 2 = Sun format           */  
                                    /* 3 = Data General format  */
                                    /* 4 = Block floating point */
   char id[4];                      /* this should always be "HFH" */
/* above defined for revision #s >= 2 */
   unsigned short slices;           /* slices */
/* above defined for revision #s >= 3 */
   char temp[3];                    /* reserved for extension  */
   } hfh_img_hdr;