Question

I am using Oracle 11g r2.

I have a table that stores images as ORDImage :

PHOTOS (phot_id integer
        , phot_filename varchar2(256)
        , phot_source ordsys.ordimage)

And another temporary table that stores an image uploaded by a user as BLOB.

INSERT_TEMP (itemp_id integer, itemp_source blob)

I want to move the BLOB image to the PHOTOS table only if does not already exists, by comparing the two images. I need to use SQL/MM Still Image methods as ORDImageSignature methods are deprecated in Oracle 11g.

Here is the code :

 declare
    [...]
 begin
    [...]
    -- get the blob from the temporary table (in_id passed as parameter)
    select itemp_source into l_img_blob from insert_temp where itemp_id = in_id;
    -- build the stillimage object from the blob
    l_img_obj := new si_stillimage(l_img_blob);
    -- get image features and build the featureList object
    l_avgcolor := new si_averagecolor(l_img_obj);
    l_colorhist := new si_colorhistogram(l_img_obj);
    l_poscolor := new si_positionalcolor(l_img_obj);
    l_texture := new si_texture(l_img_obj);
    l_featurelist := new SI_FeatureList(l_avgcolor, 1, l_colorhist, 1, l_poscolor, 1, l_texture, 1);
    -- check if a similar image already exists
    select count(*) into l_exist from photos p where SI_ScoreByFtrList(l_featurelist, SI_MkStillImage1(p.phot_source.source.localdata)) = 0;
    if (l_exist > 0) then
       out_message := app_util.get_translated_message('ERR_SIMILAR_PHOTO_ALREADY_EXISTS');
    else
       /* here the blob is inserted into the PHOTOS table as ORDImage successfully */
       out_message := app_util.get_translated_message('SUC_PHOTO_INSERTED');
    end if;
 end;

The image is inserted as ORDImage successfully if I omit the comparison, else an exception is raised (sqlcode: 1, sqlerrm: User-defined Exception), using DBMS_UTILITY.FORMAT_ERROR_BACKTRACE it tells me the following :

ORA-06512: à “ORDSYS.SI_STILLIMAGE”, ligne 27
ORA-06512: à “ORDSYS.SI_MKSTILLIMAGE1”, ligne 6
ORA-06512: à “SURV.APP_CORE”, ligne 212

line 212 is the line that checks if a similar image already exists :

 select count(*) into l_exist
 from photos p 
 where SI_ScoreByFtrList(l_featurelist, SI_MkStillImage1(p.phot_source.source.localdata)) = 0;

It seems the problem is that it does not accept p.phot_source.source.localdata as parameter. Do you have any idea on how I can solve this ?

I have also tried :

 select count(*) into l_exist 
 from photos p
 where l_featurelist.si_score(new si_stillimage1(p.phot_source.source.localdata)) = 0;

Thank you !

Answer 1

I finally came back to the problem, and get it to work.

The problem was simply that I had some null values in the ORDImage field…

---

I found my error by trying to store the StillImage object directly into my PHOTOS table :

alter table PHOTOS add phot_source2 SI_Stillimage;
update photos p set p.phot_source2 = si_stillimage(p.phot_source.source.localData) where p.phot_id < 10;

and then implementing the following minimal example :

DECLARE
    l_img_obj   si_stillimage;
    l_avgcolor  si_averagecolor;
    l_colorhist si_colorhistogram;
    l_poscolor  si_positionalcolor;
    l_texture   si_texture;
    l_featurelist   si_featurelist;
    l_blob      BLOB;
    l_exist     INTEGER;
BEGIN
    -- get the blob from the ordimage
    SELECT p.phot_source.source.localdata
    INTO l_blob FROM photos p
    WHERE phot_id = 2;
    -- build the stillimage object from the blob
    l_img_obj := NEW si_stillimage(l_blob);
    -- get image features and build the featureList object
    l_avgcolor    := NEW si_averagecolor(l_img_obj);
    l_colorhist   := NEW si_colorhistogram(l_img_obj);
    l_poscolor    := NEW si_positionalcolor(l_img_obj);
    l_texture     := NEW si_texture(l_img_obj);
    l_featurelist := NEW si_featurelist(l_avgcolor, 1, l_colorhist, 1, l_poscolor, 1, l_texture, 1);
    -- check if a similar image is found in the table
    SELECT 1
    INTO l_exist
    FROM photos p
    WHERE si_scorebyftrlist(l_featurelist, p.phot_source2) = 0
    AND phot_id < 10
    AND rownum = 1;
    -- show message if at least one similar photo has been found
    IF (l_exist = 1) THEN       
        dbms_output.put_line('A similar photo has been found');
    END IF;
END;
/ 

It was working fine when restricting the phot_id to 10, even by replacing p.phot_source2 with si_mkstillimage1(p.phot_source.source.localdata) (wich was causing the problem). But it failed when removing the phot_id restriction. So I finally understood that I had some null values in the phot_source column (ORDImage) that can cause the problem.

And indeed calling SI_StillImage() constructor with a null parameter leads to the following error message :

ORA-06510: PL/SQL: unhandled user-defined exception
ORA-06512: at "ORDSYS.SI_STILLIMAGE", line 27
ORA-06512: at "ORDSYS.SI_MKSTILLIMAGE1", line 6
ORA-06512: at line 24

I removed all null values from the phot_source column and all is working fine now 🙂

---

To go further:

The downside of this is that it takes a very long time to do the comparison with all the images stored in the table (1155 seconds (arround 20 min) for 5000 photos). So I have tried to store images features directly into the table :

alter table photos add (
    phot_averagecolor si_averagecolor,
    phot_colorhistogram si_colorhistogram,
    phot_positionalcolor si_positionalcolor,
    phot_texture si_texture
)

update photos p set
    p.phot_averagecolor = si_averagecolor(si_stillimage(p.phot_source.source.localData)),
    p.phot_colorhistogram = si_colorhistogram(si_stillimage(p.phot_source.source.localData)),
    p.phot_positionalcolor = si_positionalcolor(si_stillimage(p.phot_source.source.localData)),
    p.phot_texture = si_texture(si_stillimage(p.phot_source.source.localData))
where p.phot_id < 10

And then do the comparison like this :

-- get the blob from the ordimage
SELECT p.phot_source.source.localdata
INTO l_blob FROM photos p
WHERE phot_id = 2;
-- build the stillimage object from the blob
l_img_obj := NEW si_stillimage(l_blob);
-- get image features and build the featureList object
l_avgcolor    := si_averagecolor(l_img_obj);
l_colorhist   := si_colorhistogram(l_img_obj);
l_poscolor    := si_positionalcolor(l_img_obj);
l_texture     := si_texture(l_img_obj);
l_featurelist := NEW si_featurelist(l_avgcolor, 1, l_colorhist, 1, l_poscolor, 1, l_texture, 1);
-- check if a similar image is found in the table
SELECT 1
INTO l_exist
FROM photos p
WHERE p.phot_averagecolor = l_avgcolor
AND p.phot_colorhistogram = l_colorhist
AND p.phot_positionalcolor = l_poscolor
AND p.phot_texture = l_texture
AND p.phot_id < 10
AND rownum = 1;

But it gives the following error as it seems not possible to compare image features directly using the = operator :

ORA-22901: cannot compare VARRAY or LOB attributes of an object type
ORA-06512: at line 24

I thought a solution would be to store image features as numeric values, but I read the entire documentation and I have not found any way to get any corresponding numeric value from an image feature.

Luckily, SI_score functions are provided for each image feature, so we can use the following to compare the images :

DECLARE
    l_img_obj   si_stillimage;
    l_blob      BLOB;
    l_exist     INTEGER;
BEGIN
    -- get the blob from the ordimage
    SELECT p.phot_source.source.localdata
    INTO l_blob FROM photos p
    WHERE phot_id = 2;
    -- build the stillimage object from the blob
    l_img_obj := NEW si_stillimage(l_blob);
    -- check if a similar image is found in the table
    SELECT 1
    INTO l_exist
    FROM photos p
    WHERE p.phot_averagecolor.SI_Score(l_img_obj) = 0
    AND p.phot_colorhistogram.SI_Score(l_img_obj) = 0
    AND p.phot_positionalcolor.SI_Score(l_img_obj) = 0
    AND p.phot_texture.SI_Score(l_img_obj) = 0
    AND rownum = 1;
    -- show message
    dbms_output.put_line(l_count || ' similar photo(s) found');
END;
/

I reduced the time from 1155 seconds (arround 20 min) to 226 seconds (less than 3 min) for 5000 images.

I know, it is still very slow, but I can’t find another way to improve performances…, if anyone has an idea do not hesitate to share.