Image processing apparatus, printer and control method of the image processing
When data of one block is subjected to Huffman decoding (S 100 to S 120 ), inverse quantization processing is executed on the decoded data (S 130 ), and when a present block is a starting point block, starting point restoring information (file pointer, decoding intermediate information and DC component) for restoring the image file with the block as a starting point is stored in a predetermined area of a data buffer (S 140 , S 150 ). Then, inverse DCT calculation processing is carried out, color conversion processing is executed (S 160 , S 170 ) and the histogram of RGB values is accumulated and stored in a predetermined area of the data buffer (S 180 ).
1. An image processing apparatus for restoring compressed data of an image and subjecting the image to predetermined image processing, comprising:
a data storage module for storing data;
an information calculating and obtaining module for sequentially restoring compressed data of an indicated image from the head thereof to the extent that at least pixel information can be obtained, calculating characteristic information indicating the characteristic of the image on the basis of the pixel information, storing the characteristic information in the data storage module, obtaining starting point restoring information for restoring the compressed data with a predetermined position of the image as a starting point in a process of restoring the compressed data and storing the starting point restoring information into the data storage module;
an image generator for restoring the compressed data of the image on the basis of the starting point restoring information stored in the data storage module with the predetermined position as a starting point when an output instruction containing rotation of the indicated image is made, thereby sequentially generating the image after the rotation from the upper end thereof, and also carrying out predetermined image processing on the image after the rotation generated on the basis of the characteristic information stored in the data storage module; and
an image output module for outputting the image subjected to the predetermined image processing.
2. The image processing apparatus according to claim 1 , wherein the starting point restoring information is information containing address information in the compressed data of the image corresponding to the predetermined position.
3. The image processing apparatus according to claim 1 , wherein the predetermined position contains a position which will be the upper end when the image is rotated in a predetermined direction by a predetermined angle.
4. The image processing apparatus according to claim 1 , wherein the information calculating and obtaining module calculates the characteristic information on the basis of pixel information of predetermined sampling target pixels and stores the calculated characteristic information into the data storage module.
5. The image processing apparatus according to claim 4 , wherein the compressed data of the image is data based on the JPEG format obtained by dividing the image into blocks each comprising a plurality of pixels and then compressing the image, and
the starting point restoring information contains not only address information in the compressed data of the image corresponding to the block at the predetermined position, but also the DC component of a DCT coefficient of the block.
6. The image processing apparatus according to claim 5 , wherein the information calculating and obtaining module restores the compressed data of the image by an entropy decoding step of subjecting the compressed data of the indicated image to entropy decoding to obtain a quantized DCT coefficient, an inverse quantizing step of subjecting the obtained quantized DCT coefficient to inverse quantization to obtain a DCT coefficient, and an inverse DCT step of subjecting the obtained DCT coefficient to inverse DCT to obtain pixel information, whereby the quantized DC component of the quantized DCT coefficient in the entropy decoding step or the DC component of the DCT coefficient obtained in the inverse quantizing step is obtained as the DC component of the starting point restoring information.
7. A printer comprising:
a data obtaining module for obtaining compressed data of an image from a communicable storage medium;
a data storage module for storing data;
an information calculating and obtaining module for sequentially restoring compressed data of an indicated image from the head thereof to the extent that at least pixel information can be obtained, calculating characteristic information indicating the characteristic of the image on the basis of the pixel information, storing the characteristic information in the data storage module, obtaining starting point restoring information for restoring the compressed data with a predetermined position of the image as a starting point in a process of restoring the compressed data and storing the starting point restoring information into the data storage module;
an image generator for restoring the compressed data on the basis of the starting point restoring information stored in the data storage module with the predetermined position as a starting point when an output instruction containing rotation of the indicated image is made, thereby sequentially generating the image after the rotation from the upper end thereof, and also carrying out predetermined image processing on the image after the rotation generated on the basis of the characteristic information stored in the data storage module;
an image output module for outputting the image subjected to the predetermined image processing; and
a print executing module for printing the outputted image.
8. The printer according to claim 7 , wherein the starting point restoring information is information containing address information in the compressed data of the image corresponding to the predetermined position.
9. The printer according to claim 7 , wherein the predetermined position contains a position which will be the upper end when the image is rotated in a predetermined direction by a predetermined angle.
10. The printer according to claim 7 , wherein the information calculating and obtaining module calculates the characteristic information on the basis of pixel information of predetermined sampling target pixels and stores the calculated characteristic information into the data storage module.
11. The printer according to claim 10 , wherein the compressed data of the image is data based on the JPEG format obtained by dividing the image into blocks each comprising a plurality of pixels and then compressing the image, and
the starting point restoring information contains not only address information in the compressed data of the image corresponding to the block at the predetermined position, but also the DC component of a DCT coefficient of the block.
12. The printer according to claim 11 , wherein the information calculating and obtaining module restores the compressed data of the image by an entropy decoding step of subjecting the compressed data of the indicated image to entropy decoding to obtain a quantized DCT coefficient, an inverse quantizing step of subjecting the obtained quantized DCT coefficient to inverse quantization to obtain a DCT coefficient, and an inverse DCT step of subjecting the obtained DCT coefficient to inverse DCT to obtain pixel information, whereby the quantized DC component of the quantized DCT coefficient in the entropy decoding step or the DC component of the DCT coefficient obtained in the inverse quantizing step is obtained as the DC component of the starting point restoring information.
13. An image processing method for restoring compressed data of an image and subjecting the image to predetermined image processing, comprising using a processor to perform the steps of:
(a) sequentially restoring compressed data of an indicated image from the head thereof to the extent that at least pixel information can be obtained, calculating characteristic information indicating the characteristic of the image on the basis of the pixel information, storing the characteristic information, obtaining starting point restoring information for restoring the compressed data with a predetermined position of the image as a starting point in a process of restoring the compressed data and storing the starting point restoring information;
(b) restoring the compressed data of the image on the basis of the starting point restoring information stored in the step (a) with the predetermined position as a starting point when an output instruction containing rotation of the indicated image is made, thereby sequentially generating the image after the rotation from the upper end thereof, and also carrying out predetermined image processing on the image after the rotation generated on the basis of the characteristic information stored in the step (a); and
(c) outputting the image subjected to the predetermined image processing.
14. A computer-readable medium stored with an image processing program of restoring compressed data of an image and subjecting the compressed data of the image to predetermined image processing, wherein the image processing program is equipped with an information calculating and obtaining module for sequentially restoring the compressed data of the indicated image from the head thereof to the extent that at least pixel information can be obtained, calculating characteristic information indicating the characteristic of the image on the basis of the pixel information, storing the characteristic information, obtaining starting point restoring information for restoring the compressed data with a predetermined position of the image as a starting point in a process of restoring the compressed data and storing the starting point restoring information; an image generating module for restoring the compressed data of the image with the predetermined position as a starting point on the basis of the starting point restoring information stored in the information calculating and obtaining module when an output instruction containing rotation of the indicated image is made, thereby sequentially generating the image after the rotation from the upper end thereof, and subjecting the generated image after the rotation to predetermined image processing on the basis of the characteristic information stored in the information calculating and obtaining module; and an image output module for outputting the image subjected to the predetermined image processing.