Relational interface, basic question

Question

Hi, I have over a million images stored in a blob column.
We are using oracle 8.1.7 and forms 6.0.
We do have intermedia installed on the database but it is not
used in this application.
The images were inserted as TIFF's through a form.
Question.
Intermedia Relational interface be used to change the
compression setting of the TIFF images? using the process()
method?
Can Intermedia Relational interface be used to change the image
format of some of the images?
Thank you
David Wilton

Answer 1

Rajiv,
I like your suggestion of using the process method from a stored
procedure without having to install intermedia relational
interface. I'm not sure how to assign the ORDSYS variables to
the blob. David, please see the example below.
Our problem:
We have some TIFF images compression: CCITT group 3 and 4
(lossless compression).
Some of these images cause the forms application to crash upon
display. Forms bug, oracle sent me an oneoff for patch 9 for
forms 6i to see if this corrects the problem, it did not.
Using Forms, If I update the record and resave the image as
image type JFIF, the image can be viewed without problems.
I think when the image is saved as a JPEG some of the discarded
information might be what causes the image to crash the oracle
forms application. Therefore it no longer crashes the
application.
I am wondering if I can change the compression settings of these
problem images to JPEG and keep the image as a TIFF. or change
to a JPEG image and jpeg compression save then possibly convert
it back to TIFF.
David, if I understand your scenario correctly, your client
application is having a problem displaying certain TIFF images.
You want to modify these (by changing compression/deleting tags
etc) so that your client can display them correctly.
You should try changing the compression of these images from
CCITT 3/4 to PackBits or LZW first before trying JPEG.
In your case, using JPEG compression will explode the size of
the image data (CCITT is monochrome whereas JPEG will use 8bits)
and the image quality will also deteriorate.
If on the other hand I misunderstood your scenario and you are
having a problem with our TIFF reader with certain images, please
send us a sample problem file to investigate this further.
Here's the start of my procedure
how do I assign the ordsys variables to my blob?
thank you
David
PROCEDURE change_image IS
v_image BLOB;
v_intermed_image ORDSYS.ORDImage;
v_blob_intermed ORDSYS.ORDImgB;
BEGIN
select image_data
--into v_blob_intermed
into v_image
from obra.scanned_images
where scanned_images_rec = 1218450
for update;
-- how to assign ordsys variable to blob????
v_intermed_image := v_image;
-- v_blob_intermed := v_image;
-- keep tiff format change compression from group 3 to jpeg
ordsys.ordimage.process
(v_intermed_image, 'compressionFormat=JPEG,compressionQuality=MED
COMP');
-- change image to jpeg format
-- ordsys.ordimage.process
(v_intermed_image, 'fileFormat=JFIF,
compressionFormat=JPEG,compressionQuality=MEDCOMP');
update obra.scanned_images
set image_data = v_intermed_image
where scanned_images_rec = 1218450;
commit;
exception
     when others then
     raise;
END; PROCEDURE change_image IS
v_intermed_image ORDSYS.ORDImage;
BEGIN
select image_data
into v_intermed_image.source.localdata
from obra.scanned_images
where scanned_images_rec = 1218450
for update;
-- you can optionally invoke setProperties to inspect the image
-- v_intermed_image.setProperties ;
-- dbms_output.put_line('Height ' ||v_intermed_image.height);
-- keep tiff format change compression from group 3 to packbits
v_intermed_image.process( 'compressionFormat=PACKBITS,
compressionQuality=MEDCOMP');
-- for blobs selected for update, you don't need an additional
-- update but it doesn't hurt. If you were updating a lob
-- attribute of an object you would need the line below.
update obra.scanned_images
set image_data = v_intermed_image.source.localdata
where scanned_images_rec = 1218450;
commit;
exception
when others then
raise;
END;