Thread: Problem reading tiff image files?

Hi,

I'm currently working on some code that will need to read color tiff image files. While I have no problems working with gray scale images I have not had any luck getting color to work. At the moment all I am simply trying to do is read a color tiff image (which filename is "input.tif") and output the values of individual samples (pixel elements RGB) to the screen. (I'm intentionally not printing all image pixels to the screen at the moment.) However, what my code currently does is output partially correct results. It seems to display the first few (~10) samples fine to the screen, but then starts skipping samples. Do you guys have any ideas what may be causing that? What may be wrong with my code (listed below)?
Any suggestions/pointers would be greatly appreciated.

Thank you.

This is my code (hopefully it doesn't lose all formatting):

Code:

#include <stdio.h>
#include <iostream.h>
#include <tiffio.h>
void print_error (char *err_message);

int main()
{

double red_mean;				// mean red value of fed image

    uint32 r; 						// row index
    uint32 c; 						// column index
    uint32 rows;					// number of rows in image
    uint32 columns;					// number of columns in image
    uint16 BitsPerSample;			// normally 8 for grayscale image
    uint16 SamplesPerPixel;			// normally 1 for grayscale image
    uint16 PhotoMetric; 			// normally 1 for grayscale image
    unsigned char *in_image;		// pointer for input image array
    unsigned char *out_image;		// pointer for output image array
    TIFF *in_filep; 				// handle for input image file
    TIFF *out_filep;	 			// handle for output image file
    int	check_io;					// status of I/O operation

    // Open input image file
    in_filep = TIFFOpen("input.tif", "r");
    if (in_filep == NULL)
	print_error ("Could not open input file!");

    // Open output image file
    out_filep = TIFFOpen ("output.tif", "w"); 
    if (out_filep == NULL)
	print_error ("Could not open output file!");

    // Determine the size of the input image
    TIFFGetField(in_filep, TIFFTAG_IMAGELENGTH, &rows);
    TIFFGetField(in_filep, TIFFTAG_IMAGEWIDTH, &columns);
    TIFFGetField(in_filep, TIFFTAG_BITSPERSAMPLE, &BitsPerSample);
    TIFFGetField(in_filep, TIFFTAG_SAMPLESPERPIXEL, &SamplesPerPixel);
    TIFFGetField(in_filep, TIFFTAG_PHOTOMETRIC, &PhotoMetric);
	//TIFFGetField(in_filep, TIFFTAG_PHOTOMETRIC, &PlanarConfig);
    // The following statements are helpful in debugging
    printf ("rows = %ld\n", rows);
    printf ("columns = %ld\n", columns);
    printf ("BitsPerSample = %d\n", BitsPerSample);
    printf ("SamplesPerPixel = %d\n", SamplesPerPixel);
    printf ("PhotoMetric = %d\n", PhotoMetric);

    // Specify TIFF header fields for output image
    TIFFSetField(out_filep, TIFFTAG_IMAGELENGTH, rows);
    TIFFSetField(out_filep, TIFFTAG_IMAGEWIDTH, columns);
    TIFFSetField(out_filep, TIFFTAG_BITSPERSAMPLE, BitsPerSample);
    TIFFSetField(out_filep, TIFFTAG_SAMPLESPERPIXEL, SamplesPerPixel);
 	TIFFSetField(out_filep, TIFFTAG_PLANARCONFIG, 1);
    TIFFSetField(out_filep, TIFFTAG_PHOTOMETRIC, PhotoMetric);


    // Allocate memory to hold image arrays
    in_image = (unsigned char *) _TIFFmalloc(rows*columns);
    if (in_image == NULL) 
	print_error ("Could not allocate memory!");
    out_image = (unsigned char *) _TIFFmalloc(rows*columns);
    if (out_image == NULL) 
	print_error ("Could not allocate memory!");

    // Read image pixel values from file, row by row 
	for (r = 0; r < rows; r++)
    {
        check_io = TIFFReadScanline(in_filep, &in_image[r*columns], r, 1);
        if (check_io != 1)
	    print_error ("Could not read image from file!");
    }
	
//************************************************************************************
	// Output the first several samples (pixel elements) to screen
	red_mean = 0;
    for (r = 0; r < 3; r++)
		for (c = 0; c < 24; c++)
		//for (c = 0; c <= (columns*3); (c=c+3))
	    {
		    cout << "r = " << r << " c= " << c << " Intensity = " << (int) in_image[r*columns+c] << endl;
		}		
//************************************************************************************
   
    // Write new image to file, row by row 
    for (r = 0; r < rows; r++)
    {
        check_io = TIFFWriteScanline(out_filep, &out_image[r*columns], r, 1);
        if (check_io != 1)
	    print_error ("Could not read image from file!");
    }

    // Deallocate the image memory, close file streams, and exit
    _TIFFfree(in_image);
    _TIFFfree(out_image);
    TIFFClose(in_filep);
    TIFFClose(out_filep);
    exit (0);
}

/*****************************************************
Function name:   print_error
Description:
    Print an error message, and exit the program.
Input parameters:
    err_message -- pointer to string to be printed
Returned value:
    none
*****************************************************/
void print_error (char *err_message)
{
    fprintf(stderr, "Error:  %s\n", err_message);
    exit (1);
}