High priority Queries involving Object detection to be supported

[gaurav274]

UNNEST: #143
JOIN: TBD
ARRAY_FUNCTIONs: TBD (https://www.postgresql.org/docs/8.4/functions-array.html)

 
-- GET frames with pedestrians
SELECT id, frame
FROM DETRAC
WHERE ['pedestrain'] <@ ObjDet(frame).labels;

-- GET frames with a pedestrian and a car
SELECT id, frame
FROM DETRAC
WHERE ['pedestrain', 'car'] <@ ObjDet(frame).labels;

-- GET frames with more than 5 cars
SELECT id, frame
FROM DETRAC
WHERE array_count(ObjDet(frame).labels, 'car') > 5;

-- GET frames with 2 pedestrians and 5 car
SELECT id, frame
FROM DETRAC
WHERE array_count(ObjDet(frame).labels, 'car') = 5 
       and array_count(ObjDet(frame).labels, 'pedestrian') = 2;

-- GET frames with red cars
SELECT id, frame
FROM DETRAC, UNNEST(ObjDet(frame)) as T(label, bbox) 
WHERE label = 'car' and COLOR(frame, bbox) = 'red';

-- GET frames with cars masking 50% frame area
SELECT id, frame
FROM DETRAC, UNNEST(ObjDet(frame)) as T(label, bbox) 
WHERE label = 'car' and AREA(frame, bbox) > 0.5;

-- GET bboxes of all red cars
SELECT id, frame, bboxes
FROM DETRAC, UNNEST(ObjDet(frame)) as T(label, bbox)  
WHERE label = 'car' and AREA(frame, bbox) = 'red' 
GROUPBY id;

-- GET first 100 frames with red car
SELECT id, frame
FROM DETRAC, UNNEST(ObjDet(frame)) as T(label, bbox) 
WHERE label = 'car' and COLOR(frame, bbox) = 'red'
LIMIT 100;