VisualApplets
Operator Reference

This parameter sets the number of bits which are used to label the objects internally. It also influences the maximum number of objects which may coexist within two image lines determined by 2^label_bits. Note that the required memory resources for the blob analysis almost double with every additional bit. A good value range for this parameter is between 7 and 9 bits which should be sufficient for almost every application.

If an overflow of this address space is detected, the operator outputs error flags at bits 0 and 1 of port "ErrorFlagsO". These flags are set upon detection of the overflow and are reset with the end of the output frame.

Select the required neighborhood for object detection. See 'Definition' for a detailed explanation of pixel neighborhoods.

The maximum number of objects which may theoretically populate an image is: Input image width * input image height / 2 (equal to a check pattern using 4-connected neighborhood). This pattern is quite unlikely. Therefore, you can configure the maximum number of objects in the images via this parameter.

Select the maximum number of objects at the output. Any more objects detected by the blob analysis will be discarded. However, on port "ErrorFlagsO", an error flag at bit 2 will be set. The flag is set together with the last valid object. This parameter is disabled if "ouput_frame_size" is set to "maximum_required".

A bounding box represents the minimum paraxial rectangle which fits over the object. Each coordinate value is relatively to the top left corner of the image. The bounding box X0 represents the lowest x-coordinate of each object. It is output at "BoundingX0O". The bit width is determined from the input image. If the bounding box is not used, the bit width is set to one bit with constant zero at its output.

A bounding box represents the minimum paraxial rectangle which fits over the object. Each coordinate value is relatively to the top left corner of the image. The bounding box X1 represents the highest x-coordinate of each object. It is output at "BoundingX1O". The bit width is determined from the input image. If the bounding box is not used, the bit width is set to one bit with constant zero at its output.

A bounding box represents the minimum paraxial rectangle which fits over the object. Each coordinate value is relatively to the top left corner of the image. The bounding box Y0 represents the lowest y-coordinate of each object. It is output at "BoundingY0O". The bit width is determined from the input image. If the bounding box is not used, the bit width is set to one with constant zero at its output.

A bounding box represents the minimum paraxial rectangle which fits over the object. Each coordinate value is relatively to the top left corner of the image. The bounding box Y1 represents the highest y-coordinate of each object. It is output at "BoundingY1O". The bit width is determined from the input image. If the bounding box is not used, the bit width is set to one with constant zero at its output.

The area of an object is defined by the sum of all object foreground pixels. This parameter is used to select the required area mode. If "use_area_with_maximum_required_bits" is selected, the operator will automatically determine the required bits for the maximally possible size of an object. The maximally possible size of an object dependeds on the maximum width and height at the input link I. The theoretical maximum of an object is achieved if all pixels of an image consist of foreground values, i.e., a white input image which is one large object.

If users can be sure that their objects will not have a larger area than a specified value, this can be parameterized. Select "use_area_with_specified_bits" if the maximum object size is known. Use parameter "area_bits" to specify the number of bits. If the area is not required at all, select "area_not_used". In "area_not_used" mode, the bit width is set to one with constant zero at its output.

This parameter is enabled only if parameter "area_mode" is set to "use_area_with_specified_bits". If the area of an object is larger than the selected bits allow for, the blob analysis will output an overflow flag at bit 4 of the output link "ErrorFlagsO".

See 'Center of Gravity' for an explantion of the Center of Gravity.

Note that the output has to be divided by the area after blob analysis to get correct results.

If the parameter is set to "use_cX_width_maximum_required_bits", the operator will determine the output bits automatically. The required number of bits can get very high if large input images are used.

The number of bits is adjustable if "use_cX_with_specified_bits" is used for parameter value.

If no center of gravity in x-direction is required, it can be switched off by selecting "cX_not_used".

If "use_cX_with_specified_bits" is set for "center_of_gravity_x_mode", the bits can be changed here. Otherwise, the parameter is disabled.

If the number of bits for the center of gravity in x-direction is set manually, this parameter is activated and can be set to "used". The operator will then output a ONE at bit index 5 of the output link "ErrorFlagsO" if an overflow is detected.

See 'Center of Gravity' for an explantion of the Center of Gravity.

Note that the output has to be divided by the area after blob analysis to get correct results.

If the parameter is set to "use_cY_width_maximum_required_bits", the operator will determine the output bits automatically. The required number of bits can get very high if large input images are used.

The number of bits is adjustable if "use_cY_with_specified_bits" is used for parameter value.

If no center of gravity in y-direction is required, it can be switched off by selecting "cY_not_used".

If "use_cY_with_specified_bits" is set for "center_of_gravity_y_mode", the bits can be changed here. Otherwise, the parameter is disabled.

If the number of bits for the center of gravity in y-direction is set manually, this parameter is activated and can be set to "used". The operator will then output a ONE at bit index 6 of the output link "ErrorFlagsO" if an overflow is detected.

The contour length of an object includes all edges, even at holes. For a detailed explanation see 'Contour Length'.

If this feature is selected, the required bits can be chosen with the parameters "contour_length_bits_orthogonal_connected" and "contour_length_bits_diagonal_connected" depending on the selected neighborhood. If a 4-connected neighborhood is selected, the contour length can only be determined in orthogonal directions. If an 8-connected neighborhood is selected, the contour length is determined in orthogonal and diagonal directions.

If "contour_length_mode" is set to "contour_length_used", the bits required to represent the contour length for orthogonally connected pixels can be chosen here.

If "contour_length_mode" is set to "contour_length_used", the bits required to represent the contour length for diagonally connected pixels can be chosen here. This is only possible if an 8-connceted neighborhood is selected. Otherwise this parameter is disabled.

The contour length may cause an overflow. If the flag is used, an error flag is set at bit number 7 of port "ErrorFlagsO" in case of an overflow.